Scaffolds for tissue engineering are expected to respond to a challenging combination of physical and mechanical requirements, guiding the research towards the development of novel hybrid materials. This study introduces innovative three-dimensional bioresorbable scaffolds, in which a stiff poly(lactic acid) lattice structure is meant to ensure temporary mechanical support, while a bioactive gelatin-chitosan hydrogel is incorporated to provide a better environment for cell adhesion and proliferation. The scaffolds present a core-shell structure, in which the lattice core is realized by additive manufacturing, while the shell is nested throughout the core by grafting and crosslinking a hydrogel forming solution. After subsequent freeze-drying, the hydrogel network forms a highly interconnected porous structure that completely envelops the poly(lactic acid) core. Thanks to this strategy, it is easy to tailor the scaffold properties for a specific target application, by properly designing the lattice geometry and the core/shell ratio, which are found to significantly affect the scaffold mechanical performance and its bioresorption. Compression stiffness and strength provided by poly(lactic acid) lattices are overall within the range of values displayed by human bone tissue and remain stable after prolonged immersion in water at body temperature for several weeks. On the other hand, the hydrogel undergoes gradual and homogeneous degradation over time, but the core-shell integrity and structural stability are nevertheless maintained during at least 7-week hydrolytic degradation tests. In vitro experiments with human mesenchymal stromal cells reveal that the core-shell scaffolds are biocompatible and their physical-mechanical properties and architecture are suitable to support cell growth and osteogenic differentiation, as demonstrated by hydroxyapatite formation. These results suggest that the bioresorbable core-shell scaffolds can be considered, and further studied, in view of clinically relevant endpoints in bone regenerative medicine.

Biomass and biowaste valorisation is of major interest nowadays because of the spirit of circular economy and of the neutral environmental fingerprint global target. In the current project chondroitin sulphate (ChS) was incorporated with the crustaceous’ and shrimp’s byproduct chitosan (Chi) and the fish industry byproduct gelatine (FG) to obtain dense hydrogel membranes. Glycerol (Gly) was utilized to avoid brittleness. The formation of the hydrogel membranes is attributed to secondary interactions between the natural polymers and the plasticizer. The prepared hydrogel membranes were characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The surface morphology of the membranes was examined using scanning electron microscopy (SEM). Dynamic mechanical analysis (DMA) and tensile tests were also performed to evaluate the mechanical response of the membranes. The samples were also evaluated for membrane wettability, degradation rate and water vapor transmission rate (WVTR). Finally, in vitro endothelial cell attachment on the membrane were addressed. The overall results of the study indicate that the hydrogel membranes could be appropriate for external application in wound healing applications as dressings.

We report a modification of the freeform reversible embedding of suspended hydrogels (FRESH) 3D printing method for the fabrication of freeform perfusable microfluidics inside a hydrogel matrix. Xanthan gum is deposited into a CaCl2 infused gelatin slurry to form filaments, which are consequently rinsed to produce hollow channels. This provides a simple method for rapid prototyping of microfluidic devices based on biopolymers and potentially a new approach to the construction of vascular grafts for tissue engineering.

In the last two decades, gelatin-based hydrogels have been widely used as tissue engineering scaffolds due to their excellent biocompatibility, biodegradability, easy processability, transparency, non-toxicity, and reasonable structural similarity to the natural extracellular matrix (ECM). However, intrinsic low mechanical properties of gelatin are not structurally and mechanically suitable to support cell growth and proliferation. That’s why various crosslinking strategies including physical, chemical, enzymatic and combination of them as well as networking patterns including double network, interpenetrating network and nano reinforcing mechanism have been utilized to enhance the structural stability and mechanical integrity of gelatin. In this review, the advances in modulating the mechanical properties of gelatin-based hydrogels for the design and development of structurally stable scaffolds for tissue engineering are discussed. The optimized crosslinking parameters with the adequate mechanical properties of gelatin-based hydrogels are reviewed. Gelatin-based scaffolds for a wide range of tissue engineering applications, such as bone, cartilage, cardiac, skin, and nerve tissue engineering are also outlined. Lastly, current challenges and future perspectives in this research field are presented.

The development of biomaterial as substitution to connective tissue graft for treating gingival recession is growing nowadays. Hydrogels received attention as potential scaffold to be used in gingival tissue engineering since their capability to mimic soft tissue characteristic as they can hold amount of water. Gelatin is a natural polymer that widely used in hydrogel preparation with good biological properties, but it has poor physical stability for the used as scaffold. Chemical crosslinking strategy using EDC/NHS was performed in this study to overcome its limitation. One uncrosslinked gelatin and two crosslinked gelatin hydrogels different concentration of EDC/NHS were prepared in this study. This study investigated the difference of physical characterization from the prepared gelatin hydrogels. Our findings suggest the crosslinking strategy using EDC/NHS increase physical properties of the gelatin hydrogels without interfering the chemical structure of the gelatin. The higher crosslinker concentration will result in better morphology and more resilient to biodegradation. As a result, the crosslinked gelatin hydrogel with gelatin:EDC:NHS mass ratio of 12:1:1 met the physical characteristic for future use as scaffold for gingival tissue regeneration.

Bioactive glass (BG) represents a promising biomaterial for bone healing; here injectable BG pastes biological properties were improved by 25 wt% gelatin or chitosan, as well as mechanical resistance was enhanced by adding 10 or 20 wt% 3-Glycidyloxypropyl trimethoxysilane (GPTMS) cross-linker. Composites exhibited bioactivity as apatite formation was observed by SEM and XRD after 14 days immersion in SBF; moreover, polymers did not enhance degradability as weight loss was >10% after 30 days in physiological conditions. BG-gelatin-20 wt% GPTMS composites demonstrated the highest compressive strength (4.8±0.5 MPa) in comparison with 100% BG control (1.9±0.1 MPa). Cytocompatibility was demonstrated towards human mesenchymal stem cells (hMSC), osteoblasts progenitors and endothelial cells. The presence of 20 wt% GPTMS conferred antibacterial properties thus inhibiting the joint pathogens Staphylococcus aureus and Staphylococcus epidermidis infection. Finally, hMSC osteogenesis was successfully supported in a 3D model as demonstrated by alkaline phosphatase release and osteogenic genes expression.

Although subcutaneous islet transplantation has many advantages, transplant efficiency is still low in animal models, except in mice. We previously reported the efficacy of pretreatment using gelatin hydrogel nonwoven fabric (GHNF) in a mouse model. We investigated whether the preimplantation of GHNF could improve the subcutaneous islet transplantation outcomes in a rat model. GHNF sheets sandwiching a silicone spacer (GHNF group) and silicone spacers without GHNF sheets (control group) were implanted into the subcutaneous space of recipients three weeks before islet transplantation, and diabetes was induced seven days before islet transplantation. Syngeneic islets were transplanted into the space where the silicone spacer was removed. Blood glucose levels, glucose tolerance, immunohistochemistry, and neovascularization were evaluated. The GHNF group showed significantly better blood glucose changes than the control group (p<0.01). The cure rate was significantly higher in the GHNF group (p<0.05). The number of vWF-positive vessels was significantly higher in the GHNF group (p<0.01), and lectin angiography showed the same tendency (p<0.05). The expression of laminin and collagen III around the transplanted islets were also higher in the GHNF group (p<0.01). GHNF pretreatment was effective in a rat model, and the main mechanisms might be neovascularization and compensation of the extracellular matrices.

Hydrogel antibacterial agent is an ideal antibacterial material because of it could diffuses antibacterial molecules into the decayed area by providing a suitable microenvironment and the hydrogel acts as a protective barrier on the decay interface. The biocompatibility and biodegradation make the removal process easily which were widely used in medical fields. However, there have been few reports on its application for controlling postharvest diseases in fruit. In this study, the Chitosan-Ag (CS-Ag) complex hydrogels were prepared using the physical crosslinking method, which used for controlling postharvest diseases in grape. The prepared hydrogels were stable for a long period at room temperature. The structure and surface morphology of CS-Ag composite hydrogels were characterized by UV-Vis, FTIR, SEM, and XRD. The inhibitory effects of CS-Ag hydrogel on disease in grape caused by P. expansum, A. niger and B. cinerea were investigated both in vivo and in vitro. The remarkable antibacterial activity of CS-Ag hydrogels was mainly due to the synergistic antibacterial and antioxidant effects of CS and Ag. Preservation test showed that the CS-Ag hydrogel had positive fresh-keeping effect. This revealed CS-Ag hydrogels plays a critical role in controlling fungal disease in grape.

To prepare an edible coating with a good preservative effect on sweet cherries, carboxymethyl chitosan (CMCS) and gelatin (GL) were selected as the film-forming matrix in this experiment, and CaCl2 and ascorbic acid (AA) were added as crosslinking agents and antioxidants, respectively. First, the film was prepared by the casting method, and the film formula with better mechanical and barrier performance was filtered out by one-factor and response surface optimization test, and the differences in the preservation effect of different film formulations (CMCS-GL, CaCl2- CMCS-GL, AA -CaCl2- CMCS-GL) on sweet cherries were compared. and then the different film formulations were compared. The difference in film formulation on the preservation effect of sweet cherries was investigated. The results showed that the optimal formulation for an edible film based on CMCS-GL with good performance was CMCS: GL (w:w)=2:1, with the additional amount of 1% glycerol, 2% CaCl2, 0.1% Tween-20, 2% AA, the tensile strength, elongation at break, oxygen permeability and water vapor permeability of the film obtained with this formula were: 16.28 MPa, 71.46%, 1.39×10-12 g- cm/(cm2-s-Pa), 5.10×10-11 cm3-cm/(m2-s-Pa), respectively. In the preservation of sweet cherries, all three film formulations effectively reduced the rotting rate and weight loss during storage while preserving the high hardness and skin color of the fruit. Among them, the formulation AA -CaCl2- CMCS-GL showed the best preservation effect and can be used as a new method for postharvest preservation of sweet cherries.

Chronic and non-healing wounds demand personalized and more effective therapies for treating complications and improve patient adherence. This work aims to develop a suitable chitosan-based scaffold to provide 24 hours controlled release of DKT, by taking advantage of chitosan’s thermo-responsive behavior as well as local hyperthermia in wounds. Three formulation prototypes were developed using chitosan (F1), 2:1 chitosan: PVA (F2), and 1:1 chitosan:gelatin (F3). Compatibility tests were done by DSC, TG, and IR spectroscopy. SEM was employed to examine the morphology of the surface and inner layers from the scaffolds. In vitro release studies were performed at 32 °C and 38 °C to evaluate the release profiles, which were later adjusted to different kinetic models for the best formulation. F3 showed the most controlled release of DKT at 32 °C for 24 hours (77.75 ± 2.72 %), and reduced the burst release in the initial 6 hours (40.18 ± 1.00 %), while at 38 °C the release reached 88.52 ± 2.07 % at 12 hours. The release profile for this formulation fits with Hixson-Crowell and Korsmeyer-Peppas kinetic models at both temperatures. Therefore, the developed chitosan/gelatin thermo-responsive scaffold provides a suitable system for wound healing with a controlled release of DKT for 24 hour-use, which can overcome adherence issues and wound complications.

Our previous study found that intravesical perfusion metformin has excellent inhibitory effects against bladder cancer (BC). However, this administration route allows the drug to be diluted and excreted in urine. Therefore, increasing the adhesion of metformin to the bladder mucosal layer may prolong the retention time and increase the pharmacological activity. It is well known that chitosan (Cs) has a strong adhesion to the bladder mucosal layer. Thus, this study established a novel for-mulation of metformin to enhance its antitumor activity by extending its retention time. In this research, we prepared Cs freeze-dried powder and investigated the effect of metformin-loaded chitosan hydrogels (MLCH) in vitro and in vivo. The results showed that MLCH had a strong in-hibitory effect against proliferation and colony formation in vitro. The reduction in BC weight and expression of tumour biomarkers in orthotopic mice showed the robust antitumor activity of MLCH via intravesical administration in vivo. The non-toxic profile of MLCH was observed as well, using histological examinations. Mechanistically, MLCH showed stronger functional activation of the AMPK/mTOR signalling pathway compared with metformin alone. These findings highlighted the potential of this novel formulation as an efficient candidate for managing BC via intravesical ad-ministration.

The increasing global concern over plastic waste and its environmental impact has led to a growing interest in the development of sustainable packaging alternatives. This study focuses on the innovative use of expired dairy products as a potential resource for producing edible packaging materials. Expired dairy products, which are typically discarded, contribute to food waste and environmental pollution. By modifying these products to packaging materials, a dual-purpose solution addressing both waste reduction and sustainable packaging is evaluated. Expired milk and yogurt were selected as the primary raw materials due to their protein and carbohydrate content. The extracted casein was combined with various concentrations of chitosan while in some cases glycerol was used. The materials were characterized with attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray analysis (XRD) to examine the interactions between the components of the formed binary blend. Scanning electron microscopy (SEM) was used to evaluate the surface morphology of the blends, while dynamic mechanical analysis (DMA) and tensile experiments were conducted to study the thermomechanical properties of the materials. Barrier properties, including water vapor transmission (WVTR) and oxygen permeability (OTR), were measured to assess the materials' potential to preserve food freshness. The findings reveal that expired dairy-based edible packaging materials exhibit promising mechanical properties, comparable to conventional plastic packaging. The barrier properties and especially the zero oxygen permeability of the membranes, indicate that these materials have the potential to effectively protect food products from external factors that could compromise quality and shelf life. The materials show encouraging signs of eco-friendliness, with a notable reduction in environmental persistence compared to conventional plastic packaging.

Nitric oxide (NO) is involved in physiological processes, including vasodilatation, wound healing and antibacterial activities. As NO is a free radical, designing drugs to generate therapeutic amounts of NO in controlled spatial and time manners is still a challenge. In this study, the NO donor S-nitrosoglutathione (GSNO) was incorporated into the thermoresponsive Pluronic F-127 (PL) - chitosan (CS) hydrogel, with an easy and economically feasible methodology. CS is a polysaccharide with known antimicrobial properties. Scanning electron microscopy, rheology and differential scanning calorimetry techniques were used for hydrogel characterization. The results demonstrated that the hydrogel has a smooth surface, thermoresponsive behavior and good mechanical stability. The kinetics of NO release and GSNO diffusion from GSNO-containing PL/CS hydrogel demonstrated a sustained NO/GSNO release, in concentrations suitable for biomedical applications. The GSNO-PL/CS hydrogel demonstrated a concentration-dependent toxicity to Vero cells, and antimicrobial activity to Pseudomonas aeruginosa (minimum inhibitory concentration and minimum bactericidal concentration values of 0.5 µg·mL^-1 of hydrogel, which corresponds to 1 mmol·L^-1 of GSNO). Interestingly, the concentration range in which the NO-releasing hydrogel demonstrated an antibacterial effect was not found to be toxic to the Vero mammalian cell. Thus, the GSNO-PL/CS hydrogel is a suitable biomaterial for topical NO delivery applications.

The development of platinum group metal-free (PGM-free) electrocatalysts derived from cheap and environmentally friendly biomasses for oxygen reduction reaction (ORR) is a topic of relevant interest, particularly from the point of view of sustainability. Fe-nitrogen-doped carbon materials (Fe-N-C) have attracted particular interest as alternative to Pt-based materials, due to the high activity and selectivity of Fe-Nx active sites, the high availability and good tolerance to poisoning. Recently, many studies focused on developing synthetic strategies, which could transform N-containing biomasses into N-doped carbons. In this paper chitosan was employed as a suitable N-containing biomass for preparing Fe-N-C catalyst in virtue of its high N content (7.1%) and unique chemical structure. Moreover, the major application of chitosan is based on its ability to strongly coordinate metal ions, a precondition for the formation of Fe-Nx active sites. The synthesis of Fe-N-C consists in a double step thermochemical conversion of a dried chitosan hydrogel. In acidic aqueous solution, the preparation of physical cross-linked hydrogel allows to obtain sophisticated organization, which assure an optimal mesoporosity before and after the pyrolysis. After the second thermal treatment at 900 °C, a highly graphitized material was obtained, which has been fully characterized in term of textural, morphological and chemical properties. RRDE technique was used for understanding the activity and the selectivity of the material versus the ORR in 0.5 M H2SO4 electrolyte. Special attention was put in the determination of the active site density according to nitrite electrochemical reduction measurements. It was clearly established that the catalytic activity expressed as half wave potential linearly scales with the number of Fe-Nx sites. It was also established that the addition of the iron precursor after the first pyrolysis step leads to an increased activity because of both an increased number of active sites and of a hierarchical structure, which improves the access to active sites. At the same time, the increased graphitization degree, and a reduced density of pyrrolic nitrogen groups are helpful to increase the selectivity toward the 4e- ORR pathway.

Bone fractures are very common in the geriatric population and poses a great economic burden worldwide. While traditional methods for repairing bone defects have primarily been autografts, there are several drawbacks limiting its use. Bone graft substitutes have been used as alternative strategies to improve bone healing. However, there remains several impediments to achieving the desired healing outcomes. Injectable hydrogels have become attractive scaffold materials for bone regeneration given their high performance in filling irregularly sized bone defects, ability to encapsulate cells and bioactive molecules, and mimic the native ECM of bone. We investigated the use of an injectable chitosan-based hydrogel scaffold to promote differentiation of preosteoblasts in vitro. The hydrogels were characterized by evaluating cell homogeneity, cell viability, rheological and mechanical properties, and differentiation ability of preosteoblasts in hydrogel scaffolds. Cell-laden hydrogel scaffolds exhibited shear thinning behavior and the ability to maintain shape fidelity after injection. The CNC-CS hydrogels exhibited higher mechanical strength and significantly upregulated the osteogenic activity and differentiation of preosteoblasts as shown by ALP activity assays and histological analysis of hydrogel scaffolds. These results suggest that this injectable hydrogel is suitable for cell survival, can promote osteogenic differentiation of preosteoblasts, and structurally support new bone growth.

Periodontal diseases significantly impact about half of the global population, and their treatment often encompasses relieving symptoms as well as regenerating the destroyed tissues. Revolu-tionary research in the management of periodontal disease includes biomaterials, a boon to re-generative dentistry owing to their excellent biological properties, non-toxic, an-ti-inflammatory, biocompatible, biodegradable, and adhesion. This study aimed to fabricate an injectable fucoidan containing chitosan hydrogel and prove its effectiveness in periodontal bone regeneration. The injectable hydrogel was prepared using the sol-gel method and loaded into 2ml syringes. 40 periodontitis patients with bony defects were recruited and randomized into two groups, to re-ceive fucoidan-chitosan hydrogel and concentrated growth factor, respectively. Customized acrylic stents were used to guide the hydrogel placement into the defect site. Post-surgical changes in clinical parameters were assessed at 3, 6 and 9 months to appreciate the soft & hard tissue changes using repeated measures analysis of variance and Bonferroni’s posthoc test. Significance was kept at 5%. The fucoidan-chitosan hydrogel exhibited significantly lower probing depth values and a higher mean reduction in clinical attachment level as compared to the CGF group at the end of 3 and 6 months (p<0.05). The mean defect fills in the fucoidan-chitosan group was 1.20 at the end of 9 months (p<0.001). The presence of fucoidan in the hydrogel significantly contributed to bone re-generation in humans, thus strengthening its potential in tissue engi-neering. Fucoidan- Chitosan will be a promising biomaterial for bone tissue regeneration.

Conductive nanocomposites play a significant role in tissue engineering by providing a platform to support cell growth, tissue regeneration, and electrical stimulation. In this present study, a set of electroconductive nanocomposite hydrogels based on gelatin (G), chitosan (CH) and conductive carbon black (CB) was synthesized with the aim to develop novel biomaterials for tissue regeneration application. Incorporation of conductive carbon black (10, 15 and 20 wt %) significantly improved electrical conductivity and enhanced mechanical properties with the increased CB content. We employed an oversimplified unidirectional freezing technique to impart anisotropic morphology with interconnected porous architecture. An investigation into whether any anisotropic morphology affects the mechanical properties of hydrogel was conducted by performing compression and cyclic compression tests in each direction parallel and perpendicular to macroporous channels. Interestingly, nanocomposite with 10 % CB produced both anisotropic morphology and mechanical property, whereas anisotropic pore morphology diminished at higher CB concentration (15 and 20 %) imparting denser texture. Collectively, the nanocomposite hydrogels showed great structural stability as well as good mechanical stability and reversibility. Under repeated compressive cyclic at 50 % deformation, the nanocomposite hydrogels showed preconditioning, characteristic hysteresis, nonlinear elasticity, and toughness. Overall, the collective mechanical behavior resembled the mechanics of soft tissues. Electrical impedance associated to the hydrogels was studied in terms of modulus and phase in dry and wet condition. The electrical properties conducted in wet conditions, which is more physiologically relevant, showed low impedance at high frequencies due to capacitive currents. Overall, impedance of the nanocomposite hydrogels decreased with increased CB concentrations. These gelatin-chitosan–carbon black nanocomposite hydrogels show great promise for use as conducting substrates for the growth of electro-responsive cells in tissue engineering.

Chitosan is a copolymer of β-glucosamine and N-acetylglucosamine. Recent experiments showed that the degree and pattern of acetylation along the chitosan chain modulate the biological and physicochemical properties; however, the molecular mechanism is unknown. Here we apply the de novo all-atom molecular dynamics (MD) simulations to study chitosan’s self-assembly process at different degrees of acetylation and two different acetylation patterns. The simulations revealed that the 10-mer chitosan chains with 50% acetylation in either block or alternating patterns associate to form ordered nanofibrils comprised of mainly antiparallel chains in agreement with the fiber diffraction data of deacetylated chitosan. Surprisingly, regardless of the acetylation pattern, the same intermolecular hydrogen bonds mediate the fibril sheet formation while water-mediated interactions stabilize the sheet-sheet stacking. Moreover, the acetylated units are involved in forming the strong intermolecular hydrogen bonds (NH–O6 and O6H–O7), which offers an explanation for the experimental observation that increased acetylation lowers chitosan’s solubility. Taken together, the present study provides the atomic-level understanding the role of acetylation plays in modulating chitosan’s physiochemical properties, contributing to the rational design of chitosan-based materials with the ability to tune by its degree and pattern of acetylation. Additionally, we disseminate the improved molecular mechanics parameters that can be applied in MD studies to further understand chitosan-based materials.

Over the years, chitosan has been the subject of numerous studies and has gained significant popularity as a biomaterial due to its various characteristics, including biocompatibility, biodegradability, and bioactivity. In this work, chitosan fibres surface was modified with ursolic acid to improve their antibacterial properties by wet impregnation method. Five specimens of chitosan fibres were immersed in ursolic acid (UA) solution for varying immersion times of 1, 2, 4, 6, and 8 hours. Characterization was carried out by means of FTIR, SEM, UV-Vis spectroscopy; the results indicated an ongoing chemical reaction between chitosan and ursolic acid resulting in changes to the chemical structure. After 2 hours, the absorbance ratio remained constant; suggesting that the reaction had reached completion and the chemical structure of the sample remained stable. Antibacterial tests were performed on the resulting chitosan fibres against two bacterial strains. The fibres without ursolic acid did not exhibit any noteworthy antibacterial activity against either strain. However, the chitosan fibres modified with ursolic acid showed significant and almost strong antibacterial activity against the Gram-positive strain, S. aureus. These results suggest that chitosan fibres modified with ursolic acid could have potential applications as antibacterial materials, particularly against Gram-positive bacteria.

Chitosan's favourable characteristics, such as biocompatibility, biodegradability, and bioactivity, have made it a popular biomaterial and the subject of numerous studies over the last years. This study investigates the enhancement of mechanical properties of chitosan fibres through wet impregnation using tripolyphosphate (TPP) as cross-linker. A 1% w/v solution of TPP was prepared and five separate chitosan fibre specimens were immersed individually in TPP solution for varying times (1, 2, 4, 6, and 8 hours). The specimens were then characterized using FTIR, SEM, and dynamometry to evaluate their physical, chemical, and mechanical properties. The FTIR results indicated successful interaction between the protonated amine groups of chitosan and TPP ions, with the crosslinking reaction reaching completion after 2 hours of immersion. SEM images showed that the surface of the fibres became rougher after the crosslinking reaction, suggesting the formation of new chemical bonds. Mechanical testing revealed a significant improvement in tensile strength for the treated samples compared to untreated ones, indicating successful strengthening through crosslinking. The fibres demonstrate significant potential for use in wound healing dressings.

Because this issue journal is dedicated to Gelatin here we present a few applications of gelatin in the field of optics. It is understood that optics is the science that studies the production, propagation, interaction and detection of light. Regarding the detection there are some materials sensitive to light (photosensitive) that are used like photomultipliers, CCD’s, crystals, two dimension (2D) materials and more. Among the 2D materials the most popular through several centuries has been gelatin based photographic emulsion that records spatial distributions of light. More recently (1970) films made of Gelatin with Dichromate (DCG) and dyes have been used. We describe some characteristics and applications of these two photosensitive materials. Also we describe examples where gelatin is used as Relative Humidity (RH) sensor and in the fabrication of optical elements based on gelatin. This article is intended to researchers outside the optics community.

Objective: Regeneration of bone defects remains a challenge for maxillofacial and reparative surgeons. The purpose of this histological study was to assess the osteogenic potential of octacalcium phosphate (OCP) and bone matrix gelatin (BMG) alone and in combination in artificially created mandibular bone defects in rats. The quality of the newly formed bone was also evaluated. Methods: Thirty-six male Sprague Dawley rats (6-8 weeks old with 120-150 g weight) were randomly divided into four groups. Defects (3 mm in diameter and 2 mm in depth) were created in the mandible of rats and filled with 6 mg of OCP, BMG or a combination of both (1/4 ratio), respectively. Defects were left unfilled in the control group. To assess osteoinduction and bone regeneration and determine the quality of the newly formed bone, tissue specimens were harvested at seven, 14, and 21 days post-implantation. The specimens were processed, stained with hematoxylin and eosin (H&E) and histologically analyzed under light microscopy. Results: In the experimental groups, new bone formation was initiated at the margins of defects from seventh day after implantation. At the end of the study period, the amount of the newly formed bone increased and the bone was relatively mature. Osteoinduction and new bone formation were greater in OCP/BMG group. In the control group, slight amount of new bone had been formed at the defect margins (next to host bone) on day 21. Conclusion: Combination of OCP/BMG may serve as an optimal biomaterial for treatment of mandibular bone defects.

Chitosan is a chitin-derived fiber, extracted from the shellfish shells, a by-product of fish industry, or from fungi grown in bioreactors. In oenology, it is used for the control of Brettanomyces spp., for the prevention of ferric, copper and protein casse and for clarification. The International Organisation of Vine and Wine established the exclusive utilization of fungal chitosan to avoid the eventuality of allergic reactions. This work focuses on the differences between two chitosan categories, fungal and animal chitosan, characterizing several samples in terms of chitin content and degree of deacety-lation. In addition, different acids were used to dissolve chitosans, and their effect on viscosity and on the efficacy in wine clarification were observed. Results demonstrated that, even if fungal and animal chitosans shared similar chemical properties (deacetylation degree and chitin content), they showed different viscosity depending on the acid used to dissolve them. A significant difference was discovered on their fining properties, as animal chitosans showed a faster and greater sedimentation compared to the fungal, independently from the acid used for their dissolution. This suggests that physic-chemical differences in the molecular structure occur between the two chitosan categories and that this affect significantly their technologic (oenological) properties.

Nano/micron-sized bioactive glass (BG) particles are attractive candidates for both soft and hard tissue engineering. They can chemically bond to the host tissues, enhance new tissue formation, activate cell proliferation, stimulate the genetic expression of proteins, and trigger unique an-ti-bacterial, anti-inflammatory, and anti-cancer functionalities. Recently, composites based on bi-opolymers and BG particles have been developed with various state-of-the-art techniques for tis-sue engineering. Gelatin, a semi-synthetic biopolymer, has attracted the attention of researchers because it is derived from the most abundant protein in the body, viz., collagen. It is a polymer that can be dissolved in water and processed to acquire different configurations, such as hydro-gels, fibers, films, scaffolds, etc. Searching "bioactive glass gelatin" in the tile on Scopus renders 80 highly relevant articles published in the last ~10 years, which signifies the importance of such composites. First, this review addresses the basic concepts of soft and hard tissue engineering, in-cluding the healing mechanisms and limitations ahead. Then, current knowledge on gelatin/BG composites including composition, processing and properties is summarized and discussed both for soft and hard tissue applications. This review explores physical, chemical and mechanical features and ion-release effects of such composites concerning osteogenic and angiogenic respons-es in vivo and in vitro. Additionally, recent developments of BG/gelatin composites using 3D/4D printing for tissue engineering are presented. Finally, the perspectives and current challenges in developing desirable composites for the regeneration of different tissues are outlined.

The unique properties and morphology of liquid marbles (LMs) make them potentially useful for various applications. Non-edible hydrophobic organic polymer particles are widely used to prepare LMs. It is necessary to increase the variety of LM particles to extend their use into food and pharmaceuticals. Herein, we focus on hydrophobically modified gelatin (HMG) as a base material for the particles. The surface tension of HMG decreased as the length of alkyl chains incorporated into the gelatin and the degree of substitution (DS) of the alkyl chains increased. HMG with a surface tension of less than 37.5 mN/m (determined using equations based on the Young-Dupré equation and Kaelble-Uy theory) successfully formed LMs of water. The minimum surface tension of a liquid in which it was possible to form LMs using HMG particles was approximately 53 mN/m. We also showed that the liquid-over-solid spreading coefficient S_(L/S) is a potential new factor for predicting if particles can form LMs. The HMG particles and the new system for predicting LM formation could expand the use of LMs in food and pharmaceuticals.

Freeze drying was compared with spray drying regarding feasibility to process wild thyme drug in order to obtain dry formulations at laboratory scale starting from liquid extracts produced by different extraction methods: maceration, heat-, ultrasound-, and microwave-assisted extractions. Higher powder yield (based on the dry weight prior to extraction) was achieved by freeze than spray drying and lower loss of total polyphenol content (TPC) and total flavonoid content (TFC) due to the drying process. Gelatin as a coating agent (5% w/w) provided better TPC recovery by 70% in case of lyophilization and higher powder yield in case of spray drying by diminishing material deposition on the wall of the drying chamber. The resulting gelatin-free and gelatin-containing powders carried polyphenols in amount ~190 and 53-75 mg gallic acid equivalents GAE/g of powder, respectively. Microwave-assisted extract formulation distinguished from others by higher content of polyphenols, proteins and sugars, higher bulk density and lower solubility. The type of the drying process affected mainly position of the gelatin-derived -OH and amide bands in FTIR spectra. Spray dried formulations compared to freeze dried expressed higher thermal stability as confirmed by differential scanning calorimetry analysis and higher diffusion coefficient; the last feature can be associated with the lower specific surface area of irregularly shaped freeze-dried particles (151-223 µm) compared to small microspheres (~8 µm) in spray-dried powder.

Bio-based packaging materials and efficient drug delivery systems are gaining attention, carboxymethyl cellulose (CMC) is one of the most soluble cellulose derivatives, is a good candidate material due to its biocompatibility, biodegradability, and reproducibility. However, CMC-based films are lack of sufficient mechanical properties, limiting its widespread application. In this paper, the molecular interactions between CMC and additives with different molecular structures have been studied with rheological method. The additives are chitosan and cellulose derivatives including O-carboxymethylated chitosan (O-CMCh), N-2-hydroxypropyl-3-trimethylammonium-O-carboxymethyl chitosan (HTCMCh), hydroxypropyltrimethyl ammonium chloride chitosan (HACC), cellulose nanofibers (CNC), and cellulose nanofibers (CNF). The influencing factors, such as molecular structure, concentration of additives and temperature on the rheological properties were studied, which results revealed the information intermolecular interactions. Based on the rheological properties, several systems were selected to prepare films, which show very good transparency, wettability, mechanical properties, biodegradability, and cytotoxicity. These good characteristics of the selected films also proved the good biocompatibility of CMC and chitosan and cellulose derivatives. This work will provide an idea to prepare CMC-based food packaging and effective drug delivery materials with specific properties.

3D bioprinting holds great promise in the field of regenerative medicine as it can create complex structures in a layer-by-layer manner using cell-laden bioinks, making it possible to imitate native tissues. Current bioinks lack both the high printability and the biocompatibility required in this respect. Hence, the development of bioinks that are capable of both properties is needed. In our previous study, a furfuryl-gelatin based bioink, crosslinkable by visible light, was used for creating mouse mesenchymal stem cell-laden structures with high fidelity. In this study, lattice mesh geometries were printed in a comparative study to test against the properties of a traditional rectangular-sheet. After 3D printing and crosslinking, both structures were analysed for swelling and rheological properties, and their porosity estimated using scanning electron microscopy. Results showed that the lattice structure was relatively more porous but sturdy and exhibited a lower degradation rate compared to the rectangular-sheet. Further, the lattice allowed encapsulation of a greater number of cells, allowing them to proliferate to a greater extent compared to the rectangular-sheet that retained a lesser number of cells initially. All of these results collectively affirmed that the lattice poses as a superior scaffold design for tissue engineering applications.

Cinnamaldehyde, a natural preservative that can non-specifically deactivate foodborne pathogens, was successfully incorporated into fish skin gelatin (FSG) solutions and blow spun into uniform nanofibers. The effects of cinnamaldehyde ratios (5-30%, w/w FSG) on physicochemical properties of fiber-forming emulsions (FFEs) and their nanofibers were investigated. Higher ratios resulted in higher values in particle size and viscosity of FFEs, as well as higher values in diameter of nanofibers. Loss of cinnamaldehyde was observed during solution blow spinning (SBS) process and cinnamaldehyde was mainly located on the surface of resultant nanofibers. Nanofibers all showed antibacterial activity by direct diffusion and vapor release against Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes. Inhibition zones increased as cinnamaldehyde ratio increased. Nanofibers showed larger inhibition effects than films prepared by casting method when S. typhimurium was exposed to the released cinnamaldehyde vapor, although films had higher remaining cinnamaldehyde than nanofibers after preparation. Lower temperature was favorable for cinnamaldehyde retention, and nanofibers added with 10% cinnamaldehyde ratio showed the highest retention over eight-weeks of storage. Results suggest that FSG nanofibers can be prepared by SBS as carriers for antimicrobials.

This study developed gelatin-based films with incorporation of microcrystalline cellulose as reinforcement material. Clove (Syzygium aromaticum), nutmeg (Myristica fragrans), and black pepper (Piper nigrum) oleoresins containing antimicrobial compounds of natural origin were incorporated into films. The mechanical, thermal, optical, and structural properties, as well as color, resistance to sealing and permeability to water vapor, light, and oil of the films were determined. Adding oleoresins to the gelatin matrix increased elongation of the material and significantly diminished its permeability to water vapor and oil. Evaluation of the potential use of films containing different oleoresins as bread packaging material was influenced by the film properties. The biocomposite film containing oleoresin from black pepper was the most effective packaging material for maintaining the bread’s quality characteristics.

Development of bioresponsive extrudable hydrogels for 3D bioprinting is imperative to address the growing demand for scaffold design and efficient and reliable methods of tissue engineering and regenerative medicine. This study proposed genipin-crosslinked gelatin-hyaluronic acid hydrogel bioink with different amounts of gelatin tailored for 3D bioprinting, focusing on high cell density loading and less artificial extra-cellular matrix (ECM) effect, as well as exploring their potential applications in tissue engineering. The bioresponsiveness of these hydrogel scaffolds was successfully evaluated in different physiological conditions. 3D and four-axis printing of complex structures such as shapes of hollow tube, star, pyramid, and four-axis tubular scaffolds prove the hydrogel’s high extrusion ability and post-printing shape fidelity. Cytocompatibility and high cell density 3D bioprinting using this moderately stable hydrogel exhibit high potential for precise cell-delivery modes in tissue engineering as well as regenerative medicine.

Hybrid scaffolds based on bioactive glass (BAG) particles (<38µm), covalently linked to the gelatin (G*), using 3-glycidoxypropyltrimethoxysilane (GPTMS), have been studied for bone bioengineering. In this study, two glass compositions (13-93 and 13-93B20 [where 20% of the SiO2 was replaced with B2O3]) were introduced in the gelatin matrix. The Cfactor (Gelatin/GPTMS molar ratio) was kept constant at 500. The hybrids obtained were found to be stable at 37°C, in solution; condition at which pure gelatin is liquid. All hybrids were characterized by in vitro dissolution in TRIS solution (for up to 4 weeks) and Simulated Body Fluid (SBF) (for up to 2 weeks). Samples processed with 13-93B20 exhibit a faster initial dissolution and significantly faster precipitation of a hydroxyapatite (HA) layer. The faster ion release and HA precipitation recorded from the G*/13-93B20 samples, is attributable to the higher reactivity of borosilicate compared to the silicate glass. MC3T3-E1 cells behavior, in direct contact with the hybrids, was investigated, showing that the cells were able to proliferate and spread on the developed biomaterials. Tailoring the glass composition allows to better control the material’s dissolution, biodegradability, and bioactivity. Bioactive (especially with 13-93B20 BAG), and biocompatible, the hybrids are promising for bone application.

The objective of this study was to carry out the extraction and characterization of chitin and chitosan from the exoskeletons of the Farfantepenaeus californiensis species of shrimp, as well as its application in the formulation of polymeric films plasticized with glycerol used in the process of food packaging. The characterization of the extracted polymer was made by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and physicochemical analysis of chitin and chitosan, resulting in a theoretical performance of 29.33% and 16.46%, respectively. In terms of quality, it was determined that the extracted chitosan had a molecular weight of 1.10 x105 g/mol and a deacetylation degree of 80.23%, which classifies it as a low-molecular weight chitosan, suitable for food packaging. It was shown that the extracted chitosan is fit for the production of the films by using the casting method, presenting a tension resistance of 1 MPa. The Antibacterial analysis was carried out using Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), bacterial models commonly found in food. The results showed an effective inhibition capability of the polymeric materials. Overall, the results for both chitosan and the films indicate a high potential for application in the food packaging sector.

Arsenic is highly toxic, affecting millions of people in many regions of the world. That is why developing economic and efficient technologies is imperative to eliminate it. Sorption techniques are attractive as efficient and inexpensive sorbents can be used. Chitosan is an abundant, naturally occurring, biodegradable, low-cost biopolymer that can be combined with metal oxide to enhance its removability. This work aimed to synthesize a new chitosan-magnetite-based sorbent for arsenic removal. The synthesized sorbent does not present pores, and by FT-IR, functional groups of the chitosan and the presence of As(V) in the sorbent treated with arsenic were identified. The synthesized magnetite was characterized by XRD spectroscopy. Application of the Composite Central Design model showed that 0.22 g of the sorbent at pH 6.0 could remove 27.6% of As(V). Kinetic data, fitted with the pseudo-first and second-order models, indicated an ion exchange sorption and activation energy of 28.1-31.4 kJ mol-1. The isotherms were fitted with the Langmuir model, indicating a favourable monolayer adsorption with high affinity. The sorption energy, calculated by Dubinin-Radushkevich, 9.60-8.80 kJ mol-1, confirms a sorption mechanism mediated by ion exchange. The thermodynamic parameters of the process were ΔG°(-21.7/-19.7 kJ mol-1), ΔH°(16.7 kJ mol-1) and ΔS°(123.3 J mol-1 K-1).

The current challenges in the food packaging field are, on one side, replacing plastic from non-renewable sources with biopolymers and, on the other hand, generating a packaging material with attractive properties for the consumer. Nowadays, the consumer is concerned ecologically; the food packaging industry must ahead satisfy their needs. In this sense, incorporating several compounds with properties such as antioxidant, antimicrobial, or nutraceutical properties results attractive for the consumers. However, many of these properties can be diminished, so an encapsulation system is required. A good encapsulating system is crucial for these purposes, so polyelectrolyte complexes (PECs) can be used with that finality. Nowadays, PECs are eye-catching in many fields because of their fascinating properties, which make them very attractive, mainly for being used as encapsulating systems. Hence, this paper reviews the use of PECs in food packaging where chitosan forms polyelectrolyte complexes.

Cardiovascular diseases are the leading cause of death worldwide. Cardiovascular diseases complication can give rise to myocardial infarction which produces cell death by blockage of blood flow, leading to loss of heart function. Current treatments directed at heart repair have several disadvantages such as the lack of donors for heart transplantation or the use of non-bioactive inert materials for replacement of the damage tissue. New treatment strategies involve stimulation of heart tissue regeneration with the use of bioactive materials like chitosan, in combination with cells and biochemical factors. Chitosan scaffolds have the necessary proprieties of biocompatibility, porosity, and biodegradation, that imitates the heart extracellular matrix. Chitosan scaffolds physical proprieties, such as electrical conductivity and mechanical proprieties, can be improved by different preparation techniques and by the functionalization with other materials.

Hematite (-Fe2O3) with uniform hexagonal flakes morphology has been successfully synthesized using a combination of gelatin as natural template with F127 via hydrothermal method. The resulting hematite was investigated as adsorbent and photocatalyst for removal of ibuprofen as pharmaceutical waste. Hexagonal flake-like hematite was obtained following calcination at 500 oC with the average size was measured at 1-3 µm. Increasing the calcination temperature to 700 oC transformed the uniform hexagonal structure into cubic shape morphology. Hematite also showed high thermal stability with increasing the calcination temperatures, however, the surface area was reduced from 47 m2/g to 9 m2/g. FTIR analysis further confirmed the formation Fe-O-Fe bonds, and the main constituent elements of Fe and O were observed in EDX analysis for all samples. Fe2O3-G samples have an average adsorption capacity of 55-25.5 mg/g at 12-22% of removal efficiency when used as adsorbent for ibuprofen. The adsorption capacity was reduced with increasing the calcination temperatures due to the reduction of available surface area of the hexagonal flakes when transformed into cube. Photocatalytic degradation of ibuprofen using hematite flakes achieved 50% of removal efficiency meanwhile combination of adsorption and photocatalytic degradation further removed 80% of ibuprofen in water/hexane mixtures.

Herewith we report a facile synthesis of zinc oxide doped with (5, 10, 15, and 20 wt%) titanium oxide nanocomposites in gelatin under ultra-sonication. The X-ray diffraction (XRD) data revealed ZnO the formation in addition to a rutile phase TiO2. The ZnO phase size decreased, and the rutile TiO2 phase increased with a TiO2 loading increment. The scanning electron microscopy (SEM) displayed a combination of spherical and hexagonal particles with a 60 – 80 nm size distribution. The prepared nanostructures photocatalytic activity was assisted using Rhodamine B dye, where they showed enhanced photodegradation competence under visible light irradiation. The kinetics of photodegradation followed the first-order kinetics with the 20 % wt sample having the maximum activity. The mechanistic investigation revealed the dominance of h+ and •O2- species during the dye photodegradation. The results indicate the potential application of such gelatin stabilized nanostructures for dye illumination from aqueous solutions under sunlight.

This study aimed to characterize the antioxidant, mechanical and physical properties of chicken skin gelatin/CMC/Centella asiatica blended film. The influence of Centella asiatica at 0.3% and 0.7% on antioxidant activities; mechanical properties and physical properties of chicken skin gelatin/CMC/Centella asiatica film were investigated. Characterization of the blended films with 0.7% Centella asiatica extract shows higher antioxidant activities with a total phenolic content of 0.36 mg/g of GAE, DPPH of 89.26%, and reducing power of 0.80 nm compared to 0.3% Centella asiatica extract. The addition of 0.3% of Centella extract provide higher value in tensile strength (5.0 × 10⁻² MPa), elongation at break (281%), melting point (131.31 °C), transparency (0.86) but lower UV-light penetration. While the addition of 0.7% Centella extract contribute to higher value in WVP (1.13 × 10⁻⁴ g m⁻¹s⁻¹Pa⁻¹) and puncture test (0.06 N). There are no significant differences between functional groups obtained from this blended film as evaluated by FTIR analysis (p > 0.05). Furthermore, XRD analysis showed the addition of extract decrease the crystallinity of film. In conclusion, the incorporation of Centella asiatica extracts on film greatly increased antioxidant levels and improved some of the mechanical and physical properties of the film blends.

Iron deficiency anemia (IDA) is a world health problem for humans and other mammals; affecting critical stages of development. Pigs have been used as an experimental model for the study and prevention of anemia because of physiological and metabolic similarities with humans. Iron dextran particles (IDP) are used for intramuscular (IM) IDA treatments in pigs, but are insufficient for prevention of anemia due to quick metabolization. Therefore, the objective of this study was to develop chitosan thermosensitive hydrogels (CTH) formulations and to study their potential as a mammalian parenteral iron dextran supplementation strategy. CTH were loaded with IDP at increasing iron concentrations (0.1, 0.2 and 0.4 g of theorical iron/g of chitosan) and characterized as an IM iron supplement. All the CTH-IDP formulations were thermosensitive and can be injected IM at ~4 °C, with a significant rise in viscosity between 25-37 °C. IDP content was physically trapped in the chitosan hydrophobic gel at 37 °C, without evidence of chemical bonding. We conclude that CTHs are a promising strategy for IM delivery strategy of IDP, and these results may be useful for future iron supplementation studies in pigs, humans and other mammals.

Nowadays, inherently safer designs are considered as key priorities to prevent or mitigate serious incidents with devastating consequences. The need for process safety assessment during early design phases has motivated the development of several contributions related to computer-aided assessment methodologies in order to measure the inherent safety of chemical processes. In this work, the large-scale production of chitosan from shrimp wastes was evaluated from process safety point of view using the numerical descriptive inherent safety technique (NuDIST).To this end, simulation of the chitosan production was performed using Aspen Plus ® to obtain extended mass and energy balances. The assessment of all the chemicals involved within the process was carried out for the following safety parameters: explosivity (EXP), flammability (FL) and toxicity (TOX). The safety assessment of the process included the parameters of temperature (T), pressure (P) and heat of reaction (HR). The maximum chemical safety score was estimated in 171.01 with ethanol as main contributor to the parameter of explosivity and flammability. The score associated with operating data was calculated in 209.30 and heat of reaction reported to be the most affecting parameter. The NuDIST score was estimated in 380.30. This NuDIST value revealed the low hazards associated with the handling of substances such as shrimp wastes, chitosan and water, as well as the non-extreme temperature and pressure conditions. In general, the large-scale production of chitosan from shrimp shells showed to be an inherently safe alternative of waste valorization.

The main aim of this work is to report an alternative energy efficient technique of fabricating flexible thermoelectric generators (TEGs) using printable ink. In this process, we have fabricated thermoelectric (TE) composite thick film and we are experimenting several ways to overcome the challenges of conventional and additive manufacturing methods. Two different mesh sizes of n-type bismuth particle, various binder to thermoelectric (TE) material weight ratio, and two different pressure (200 MPa and 300 MPa) were employed for optimizing the thermoelectric properties of TE composite films. We are also exploring naturally occurring chitosan as a binder. Dimethyl sulfoxide (DMSO) dissolved chitosan was used for the binder and less than 0.2 wt% of chitosan was sufficient for the fabrication of TE inks and composite films. Low energy intensive curing process was employed to evaporate the solvent from the drop casted inks. External uniaxial pressure not only eliminated high energy intensive curing processes but also increased the packing density of the film by removing pores and voids in the chitosan-bismuth composite film. The microstructure analysis reveals that bulk-like structure, which rarely has voids, pores and grain boundaries, was observed in the composite films pressed at sufficiently high pressures. The highest performing composite film was obtained with the conditions of 1:2000 binder to bismuth weight ratio, 100 mesh of particle size, and 300 MPa of pressure. The best performing bismuth chitosan composite film pressed at 300 MPa had the power factor as 4009 ± 391 μW/m·K² with high electrical conductivity value of 7337 ± 522 S/cm. The measured thermal conductivity of the best performing chitosan-bismuth composite film was 4.4 ± 0.7 W/m·K and the figure of merit calculated from the thermal conductivity was 0.27 at room temperature.

Transport of hydrophobic drugs in the human body exhibits complications due to the low solubility of these compounds. With the purpose of enhancing the bioavailability and biodistribution of such drugs, recent studies have reported the use of amphiphilic molecules, such as phospholipids, for synthesis of nanoparticles or nanocapsules. Given that phospholipids can self–assemble in liposomes or micellar structures, they are ideal candidates to function as vehicles of hydrophobic molecules. In this work, we report mesoscopic simulations of nanoliposomes, constituted by lecithin and coated with a shell of chitosan. The stability of such structure and the efficiency of encapsulation of capsaicin, as well as the internal and superficial distribution of capsaicin and chitosan inside the nanoliposome were analyzed. The characterization of the system was carried out through density maps and the potentials of mean force for the lecithin–capsaicin, lecithin–chitosan and capsaicin–chitosan interactions. The results of these simulations show that chitosan is deposited on the surface of the nanoliposome, as has been reported in some experimental works. It was also observed that a nanoliposome of approximately 18 nm in diameter is stable during the simulation. The deposition behavior was found to be influenced by pattern of N-acetylation of chitosan.

Enzymes serve as biocatalysts for innumerable important reactions; however, their application has limitations, which could be overcome by using appropriate immobilization strategies. Here, a new support for immobilizing enzymes is proposed. This hybrid organic-inorganic support is composed of chitosan—a natural, nontoxic, biodegradable, and edible biopolymer—and sodium polyphosphate, which was the inorganic component. Lipase B from Candida antarctica (CALB) was immobilized in microspheres by encapsulation using these polymers. The characterization of the composites (by infrared spectroscopy, thermogravimetric analysis, and confocal Raman microscopy) confirmed the hybrid nature of the support, whose external part consisted of polyphosphate and core was composed of chitosan. The immobilized enzyme had the following advantages: possibility of enzyme reuse, easy biocatalyst recovery, increased resistance to variations in temperature (activity declined from 60°C and the enzyme was inactivated at 80°C), and increased catalytic activity in the transesterification reactions. The encapsulated enzymes were utilized as biocatalysts for transesterification reactions to produce the compound responsible for the aroma of jasmine.

Gelatin fibers have a specific surface and high porosity, which is why their use in medicine and the food industry is being researched. This article explores the potential of centrifugal spinning to produce gelatin fibers. Gelatin for fiber preparation is obtained from a non-traditional source of collagen (chicken by-products) using a unique enzymatic process. The fiber quality is compared with those prepared from traditional collagen tissues (porcine, bovine). The results show that fibers crosslinked with glutaraldehyde vapor preserve their structure even in contact with water. Using a cross-linker controls swelling ability and solubility while maintaining the fiber structure. On the contrary, uncross-linked gelatin fibers are water soluble due to a high surface-to-volume ratio, facilitating water penetration and dissolution. Scanning electron microscopy (SEM) provided a clearer picture of the morphology of gelatin fibers obtained by centrifugal spinning. Differences in the amount of bonding depending on the raw material used and the presence of cross-linker were analyzed using Fourier transform infrared spectroscopy (FTIR). The overall results showed that chicken gelatin is a suitable alternative to gelatins from traditional sources.

Chicken collagen is a promising raw material source to produce gelatins and hydrolysates. Gelatins and hydrolysates can be prepared biotechnologically using proteolytic enzymes produced by submerged fermentation of genetically modified microorganisms. By choosing the appropriate process conditions, such changes can be achieved at the molecular level of collagen, making it possible to prepare products with targeted properties for advanced cosmetic, pharmaceutical, medical or food applications. The research aims to investigate: i) antioxidant activity (DPPH and ABTS) in model samples of chicken collagen products (gelatin and hydrolysates); ii) distribution of molecular weights by the GPC-RID analysis method; iii) functional groups and configuration of polypeptide chains related to molecular level properties using FTIR; iv) the microbiological properties on SDA, PCA, TSA and VRBL microbial populations using MALDI method. Antioxidant activity towards ABTS radicals of more than 80% was found for all samples. The molecular weights of all gelatin samples showed typical α- and β-chains. FTIR analysis confirmed that the samples showed all typical vibrational regions for collagen cleavage products, Amide A and B, Amide I, II, and III at characteristic values. Microbiological analysis of the prepared samples showed no undesirable bacteria that would limit advanced applications of the prepared products. Gelatins and hydrolysates from chicken stomachs represent a promising alternative to products made from standard collagen tissues of terrestrial animals.

Waste from fish cutting (heads, swim bladders, fins, skin, bones) is a high-value technological raw material for obtaining substances and products based on them with a wide range of properties. The possibility of using waste from cutting fish of the Gadidae family: the Alaska pollock (Gadus chalcogrammus) and the Pacific cod (Gadus macrocephalus), processed in the coastal zone, is scientifically substantiated. In this work, a technology has been developed for processing accumulated waste from fish cutting in order to obtain fish gelatin, which is characterized by high protein content (more than 80.0%) and a full set of essential and nonessential amino acids. We studied the quality of fish gelatin obtained from wastes from cutting the fish of the Gadidae family. The possibility of using fish gelatin as a component of fish products is shown; the dose of its introduction into the fish products is substantiated. The data obtained made it possible to recommend the use of fish processing waste products as a gelling component and a source of amino acids in multicomponent food systems.

The release of the active substance from the matrix modified-release tablets based on Kollidon®SR and chitosan depends on its solubility in the dissolution medium and on the composition of the matrix-forming polymers. The study is based on new oral matrix tablets based on Kollidon®SR and chitosan, formulated to optimize the low oral bioavailability of chlorzoxazone, a non-steroidal anti-inflammatory drug, a class II Biopharmaceutical Classification System. Nine types of chlorzoxazone matrix tablets were obtained using the direct compression method, and their combination at 1:1, 1:2, 1:3 chlorzoxazone/ excipients, 20%-40% (w/w) Kollidon®SR, 3-7% (w/w) chitosan and the auxiliary substances were formulated in constant concentrations. Pharmaco-technical characterization included the analysis of flowability and compressibility properties (flow time, friction coefficient, angle of repose, Hausner ratio, Carr Index), and of pharmaco-chemical characteristics (mass and dose uniformity, thickness, diameter, mechanical strength, Friability, degree of softening, in vitro release profile) of the tablets. Based on the initial evaluation of the pharmaco-technical analysis, pharmaco-chemical characteristics, and in vitro release profile, only three matrix tablet formulations (F1b, F2b, and F3b) were further tested. They were evaluated through Fourier-transform infrared spectrometry, X-ray Diffraction, thermogravimetry, differential scanning calorimetry, and in vitro dissolution tests. The three formulations were comparatively studied regarding the release kinetics of active substances using in vitro release testing. The results were analyzed by fitting into four representative mathematical models for the modified release oral formulations. In vitro kinetic study reveals a complex mechanism of release occurring in the first (0 - 2 hours) and second (2.0 hours – 36 hours) steps of drug release. Two factors have been calculated to assess the release profile of chlorzoxazone: f1 - the similarity factor and f2 - the factor difference. The results have shown that both Kollidon®SR and chitosan may be used as matrix-forming agents when combined with chlorzoxazone. In vitro dissolution tests revealed the F2b sample, data suggesting a faster drug release. The three formulations showed optimum pharmaco-technical properties and in vitro kinetic study, and they had tremendous potential to be used in oral pharmaceutical products for the controlled delivery of chlorzoxazone.

A single water pollution by dyes is a huge environmental problem; there is a necessity to produce new decolorization methods that are effective, cost-attractive, and suitable in industrial use. Magnetic chitosan polymers offer the advantage of easy separation from the dye solution. In this work, a Chitosan-Fe polymer was synthesized, characterized, and tested for removal of the azo dye Direct Red 83:1 from water. The polymer was characterized in terms of surface morphology (SEM), elemental analysis (EA), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), infrared spectrophotometry (IR), X-ray powder diffraction (XRD) and density functional theory (DFT). The reported results hint that 1 g and pH 7.0 were the best conditions to carry out both kinetic and isotherm models. To understand the adsorption behavior of Direct Red 83:1 onto the polymers, adsorption rate and maximum adsorption capacity were calculated using kinetic tests and isotherm curves respectively. The kinetic data and mechanism of the adsorption process were analyzed by three models and the equilibrium data by three adsorption isotherms. The results indicated that the adsorption process follows a pseudo-second-order kinetics (R2= 0.999) and fits the Temkin isotherm (R2= 0.946), indicating that the adsorption occurred on heterogeneous surfaces. The newly synthesized Chitosan-Fe polymer exhibited good adsorption properties and easy separation of cleaned water.

Abstract: Nowadays, there is an increasing interest in the development of novel bioresorbable membranes for Guided Bone Regeneration (GBR). Hydroxyapatite of different resources in com-bination with chitosan has been used successfully. In this work, armored catfish (Pterygoplich-thys spp) bone as a source of hydroxyapatite is proposed; it was isolated through bone calcina-tion at a temperature of 1000 °C. The hydroxyapatite obtained was analyzed for its chemical composition by means of Energy Dispersive Spectroscopy (EDS), its functional groups by Fouri-er Transform Infrared Spectroscopy (FT-IR), its crystallographic structures were analyzed by X-ray diffraction (DRX) and Scanning electron microscopy (SEM) was used to observe the mor-phology of the particle. The composed membrane presents a major roughness morphology sur-face than the pristine chitosan membrane. The hydroxyapatite particles added to the polymeric matrix increased the mechanical tensile properties of the membrane. These findings confirm that armored catfish bones are a viable, economic, and environmentally friendly source of hydroxy-apatite, which combined with chitosan, is a suitable alternative to develop biocompatible GBR membranes after it is combined with chitosan.

Type 2 Diabetes Mellitus (T2DM) is one of the most common metabolic disorders, with a major involvement of oxidative stress in its onset and progression. Pioglitazone (Pio) is an antidiabetic drug which primarily works by reducing insulin resistance while Curcumin (Cur) is powerful antioxidant with o important hypoglycemic effect, also. The both drugs are associated with several drawbacks, such as reduced bioavailability, a short half-life time (Pio) as well as instability and poor water solubility (Cur), which limit their therapeutic use. In order to overcome these disadvantages, a new co-delivery (Pio, Cur) nanosystem based chitosan (CS) (CS-Pio-Cur NPs), was developed, and characterized in reference with simple nanosystems (CS-Pio NPs, CS-Cur NPs). The developed CS-based NPs (CS-Pio-Cur NPs, CS-Pio NPs, CS-Cur NPs) were physico-chemical characterized in terms of particle size (PS), entrapment efficiency (EF%) and loading capacity (LC%). The CS-Pio-Cur NPs proved increased or similar values of EE (88.95% ± 7.79 for Cur; 94.83% ± 9.89 for Pio) and LC% (24.25 % ± 1.62 for Cur; 3.5% ± 0.98 for Pio), in reference with simple nanosystems, CS-Cur NPs (EE = 82.46% ± 1.74; LC = 20.34% ± 0.94) and CS-Pio NPs) (EE = 96.31% ± 0.68; LC = 4.11% ± 0.47), respectively. The identification of APIs (Cur, Pio) loaded into CS matrix was performed using FR-IR spectroscopy and for simultaneously quantification of APIs (Cur, Pio) released from CS-Pio-Cur NPs, a HLPC method was developed and validated. Based on release study performed in different simulated fluids (SGF, SIF, SCF) it can be appreciated that developed CS-APIs NPs have favorable pharmacokinetic profile with good release in gastrointestinal tract.

Chitosan nanoparticle delivery systems have potential for enhancing bone healing and addressing osteomyelitis. The objective was to deliver antimicrobial agents capable of preventing or treating osteomyelitis. Each formulation was optimized to achieve desired characteristics in terms of size (ranging from 100 to 400 nm), PDI (less than 0.5), zeta potential (typically negative), and in vitro release profiles for gentamicin. Entrapment percentages varied with gentamicin ranging from 10% to 65%. The chitosan nanoparticles exhibited substantial antimicrobial efficacy, particularly against both P. aeruginosa and MRSA, with zones of inhibition ranging from 13 to 24 mm and complete reduction in colony forming units observed between 3 to 24 hours. These chitosan nanoparticle formulations loaded with antimicrobials hold promise for addressing orthopedic complications.

Oxidized sucrose (OS) reacts with amino group-containing polysaccharides, including chitosan, without catalyst, resulting in hydrogels entirely composed of carbohydrates. The presence of imine bonds with low structural stabilities and unreacted aldehydes in the structures of these hydrogels hinder their application as biomaterials. Therefore, herein, the chitosan hydrogels (CTSGs) obtained after the crosslinking of chitosan with OS were reduced using sodium borohydride to convert imine bonds to secondary amines and aldehydes to alcohols. Structures of CTSGs were comprehensively characterized by Fourier transform infrared and 13C nuclear magnetic resonance spectroscopies, and results implied that the degree of crosslinking (CR) depended on the OS feed amount used during CTSG preparation. Properties of CTSGs were significantly dependent on CR; with an increase in CR, thermal stabilities and dynamic moduli of CTSGs increased, whereas their swelling properties decreased. CTSGs exhibited antimicrobial properties against the gram-negative bacterium Escherichia coli, and their performances were also dependent on CR. Results indicated the potentials of CTSGs completely based on carbohydrates as antimicrobial hydrogels for various medical and pharmaceutical applications. We believe that this study will contribute to the development of hydrogels for application in the food, medical, and pharmaceutical fields.

Risedronate sodium (RIS) possesses very low bioavailability and several adverse effects in the gastrointestinal tract when administered through an oral route. Thus, this necessitates the need to develop novel formulation. Hence, we had developed RIS-HA-TCS loaded mPEG coated nanoparticles for the treatment of osteoporosis. Chitosan was used to synthesize thiolated chitosan and its characterization was done using DSC and FTIR. Ellman's reagent was used to measure the degree of thiol immobilization. The RIS-HA fabrication was done and was further conjugated with the synthesized TCS. The Box-Behnken design process was used for designing fifteen batches of RIS-HA-TCS nanoparticles, which were formulated by ionic gelation procedure in which tripolyphosphate (TPP) was used as a crosslinking agent. Moreover, RIS and RIS-HA-TCS in-silico activity was compared for farnesyl pyrophosphate synthetase enzyme. The obtained results revealed that the binding affinity of RIS was much more than the conjugated RIS. Successful docking results paved the way for thiolation of chitosan with RIS. The drug entrapment efficiency (%EE), particle size and Polydispersity index (PDI) of RIS-HA-TCS nanoparticles obtained were 85.4 ±2.21%, 252.1 ±2.44 nm and 0.2± 0.01 respectively. The particle size, PDI, and encapsulation efficiency of RIS-HA-TCS were reported to be 264.9 ±1.91 nm, 0.120± 0.01, and 91.1 ±1.17%, respectively, after being further conjugated with mPEG. TEM showed the spherical particle size of RIS-HA-TCS and RIS-HA-TCS-mPEG. The in-vitro release of RIS-HS-TCS-mPEG was found to be significantly higher (95.13±4.64%) as compared to RIS-HA-TCS (91.74 ± 5.13%), RIS suspension (56.12 ± 5.19%) and marketed formulation (74.69 ± 3.98%). In an ex-vivo gut permeation study, RIS-HA-TCS-mPEG nanoparticles was found to have an apparent permeability of 0.5858×10-1 cm/min which was better than the apparent permeabilities of RIS-HA-TCS formulation (0.4011 ×10-4cm/min), RIS suspension (0.2005 ×10-4 cm/min) and marketed preparation (0.3401 ×10-4 cm/min)..

This work deals with the synthesis of bare and curcumin (CUR)-loaded chitosan (CS)-based macroparticles by ionic gelation using sodium hydroxide (NaOH) or sodium tripolyphosphate (TPP) as cross-linking agents. The resulting spherical-shaped macroparticles were studied using various characterization techniques, Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). The release of CUR from the CS-based particles with respect to time was analyzed, and the encapsulation efficiency and degree of swelling were studied. All formulations showed excellent CUR trapping efficiency, exceeding 90%. In particular, the TPP-crosslinked macrobeads released 34 wt% of the charged CUR within minutes, while the remaining 66 wt% was released slowly due to the biodegradation of CS. The results indicate that the correct choice of gelling agent and its concentration leads to spherical particles capable of encapsulating CUR and releasing it in a wide range of kinetics depending on the specific application.

Chitosan and its derivatives as a biocompatible, biodegradable polymer that has been well-established in biotechnology and medicine as the nanogels and nanofilms forming material, has a number of practical applications in the field of the supply of medicines, food colloids, agrotechnology, as well. In this paper, the focus of attention is directed to the study of the physico-chemical principles of the formation of gels and nano-particles using fluorescence spectroscopy methods. We have obtained chitosan (Chit5) and pegylated chitosan (Chit5-PEG) particles with an average size of 170 or 400 nm, respectively by counterflow extrusion method. The paper presents three based fluorescent probes sensitive to the formation of chitosan particles: congo red, malachite green as well as covalently attached pyrene-label. Dyes fluoresce about an order of magnitude brighter in the composition of chitosan nanogel particles or in mscrogels. With these fluorescence probes, the pH- and temperature-dependent behavior of polymers was studied, and the influence of the genipin -based crosslinking agent on the gel formation parameters, such as kinetics and concentration dependence of the nanoparticles formation accompanied by sharply increases in the fluorescence intensity of dyes was evaluated. A sensitive approach for tracking gelation and including of small drug molecules and protein by FRET using a pyrene-tryptophan donor-acceptor pair is proposed using tryptophan or ovalbumin as fluorophores-donors. Upon nanogel formation FRET effect is observed manifested in sharp increase if the fluorescence intensity of the pyrene (acceptor). Thus, the application of the fluorescent probes with FRET function for monitoring the gelation and nanoparticles formation as well as drug encapsulation in chitosan-based parts, which have broad prospects in biomedical practice and food industry.

With the objective of studying the influence of elicitors on growth, yield and quality of kalmegh we carried out an investigation for two consecutive years. Nine treatments with three replications were laid out in CRD design. Chitosan, Yeast extract, Jasmonic acid and Salicylic acid were evaluated at different concentrations. CHT 1000 ppm exhibited highest plant height (73.91 cm) and secondary branches (29.07) at the time of harvest. Primary branches and number of leaves per plant were highest in CHT 1000 ppm (26.36; 88.32) which were on par with SA 200 ppm (26.28; 81.51). Plant spread was highest in SA 200 ppm (35.46 cm2) which was on par with CHT 1000 ppm (35.11 cm2). CHT and SA sprays were recorded with on par results for yield parameters but highest fresh (42.34 g) and dry (18.30) herbage yield per plant were exhibited with SA 200 ppm. Highest total chlorophyll (4.459 mg g-1) and total andrographolides (3.494%) content were recorded in SA 200 ppm spray. Significant and positive improvement in growth, yield and quality of kalmegh was noticed with Salicylic acid spray @ 200 ppm at 30 and 60 DAS signifying its use in cultivation of kalmegh for high productivity, quality and better returns for farmers.

Hepato-renal dysfunctions associated with hyperlipidemia necessitates continuous search for natural remedies. This study thus, evaluated the effect of dietary chitosan on diet-induced hyperlipidemic rats. Thirty male Wistar rats (90 ± 5.2) g were randomly allotted into six (6) groups (n=5): Normal diet, High-fat diet (HFD), Normal diet + 5% chitosan. The three other groups received HFD, supplemented with 1%-, 3%-, and 5% of chitosan. The feeding lasted for 8 weeks, after which the rats were sacrificed. The liver and kidneys were harvested for Analyses. Hepatic alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activity, and renal biomarkers (ALT, AST, urea, and creatinine) were assayed spectrophotometrically. Additionally, expression of hepatic and renal CD43 and p53 was estimated immunohistochemically. Hyperlipidemia caused a significant (p<0.05) decrease in the hepatic (AST, ALT, and ALP) and renal (AST and ALT) activities, while renal urea and creatinine increased. Furthermore, the HFD group showed an elevated level of hepatic and renal CD43 while p53 expression decreased. However, groups supplemented with chitosan showed improved hepatic and renal biomarkers, as well as corrected the aberrations in the expressions of p53 and CD43. Conclusively, dietary chitosan could effectively improve kidney and liver functionality via abatement of inflammatory responses.

In this work, nanochitosan (NC) was prepared through ionic gelation using low-molecular-weight chitosan and maleic acid (MA). The synthesized NC was charac¬terized by means of Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). In the course of preparation, the particle size of the material was strongly depended on the parameters such as chitosan concentration and pH of the solution. By controlling the above parameters, NC with the size of smaller than 100 nm was prepared. The chitosan and prepared NC were used for the adsorption of Pb (II) from aqueous solutions in a batch system. Among the sorption parameters, pH showed the strongest effect on the sorption process and maximum Pb (II) removal was obtained at pH value of 6. The pseudo-first-order and pseudo-second-order were used to track the kinetics of adsorption process. Langmuir and Freundlich isotherms were subjected to sorption data to estimate the sorption capacity. NC proved to be an excellent adsorbent with remarkable capacity to remove Pb (II) ions from the aqueous solutions at various concentrations. The NC also showed incredible performance with a comparatively easier preparation process than other reported work.

Sub-micron o/w emulsions coated with chitosan have been used for drug delivery, quorum sensing inhibition and vaccine development. To study interactions with biological systems, nanocapsules have been fluorescently labelled in previous works, but it is often difficult to distinguish the released label from intact nanocapsules. In this study, we present advanced labelling strategies based on FRET measurements for chitosan-coated nanocapsules and investigate their dissolution and degradation. We used FRET measurements of nanocapsules loaded with equimolar concentrations of two fluorescent dyes in their oily core and correlated them with DLS count rate measurement and absorbance measurements during their disintegration by dissolution. Using count rate measurements, we also investigated the enzymatic degradation of nanocapsules using pancreatin and how protein corona formation influences their degradation. Of note, nanocapsules dissolved in ethanol, where FRET decreased simultaneously with count rate, and absorbance caused by nanocapsule turbidity, indicating increased distance between dye molecules after their release. Nanocapsules were degradable by pancreatin in a dose dependent manner, and showed a delayed enzymatic degradation after protein corona formation. We present here novel labelling strategies for nanocapsules that allow us to judge their status and an in vitro method to study nanocapsule degradation and the influence of surface characteristics.

Versatile hybrid organic polymers are prepared using two active intermediates such as cynuric chloride and chitosan derivatives. The prepared chalcones are characterized by using FT-IR, UV, and proton NMR, thermal analysis and Minimum inhibitory Concentration. Thermal stability of the synthesized hybrid polymer is found using TGA and the hybrid chitosan derivative chalcone is thermally stable up to 270 °C. The antimicrobial activity of the prepared chitosan containing chalcone moiety are find out using Minimum Inhibitory Concentration (MIC) method. The synthesized versatile chalcone shows excellent antimicrobial activity against gram-negative bacteria such as Pseudomonas aeruginosa; and Gram-positive bacteria Chalcone containing halogen moiety shows high activity (MIC 7.8 µg/mL) than the hydroxyl containing chalcone. Cytotoxicity activity of the synthesized composites shows high activity.

Alginate-gelatin hydrogels are extensively used in bioengineering. However, despite different formulations being utilized for growing different cell types in vitro, their pH and its effect, together with the crosslinking ions, of those formulations are still infrequently assessed. In this work we studied how these elements can affect hydrogel stability and printability and influence U2OS and NIH/3T3 cell viability and metabolism on the resulting 3D prints. In this context, 6% alginate + 2% gelatin hydrogels were prepared with 0.1 M MES buffer with pH 5.5, 6.5, 7.0 or 8.0, printed by extrusion-based 3D printing, and crosslinked immediately after printing with either CaCl2 or BaCl2. Our results showed that both the buffer pH and the crosslinking ion (Ca2+ or Ba2+) influence the swelling and degradation rates of the prints. Moreover, the buffer pH influenced the printability of the hydrogel in air, but when printed directly in a fluid-phase CaCl2 or BaCl2 crosslinking bath. In addition, both U2OS and NIH/3T3 cells showed greater cell metabolic activity on one-layer prints crosslinked with Ca2+. Besides, Ba2+ increased cell death of NIH/3T3 cells while had no effect on the U2OS cell viability. The pH of the buffer also caused an important impact on the cell behaviour. U2OS cells showed a 2.25-fold cell metabolism increase on one-layer prints prepared at pH 8.0 in comparison to those prepared at pH 5.5. Whereas, NIH/3T3 cells showed greater metabolism on one-layer prints with pH 7.0. Finally, we observed a difference on cell arrangement of the U2OS cells growing on prints prepared from hydrogels with acidic buffer in comparison to cells growing on those prepared using neutral or basic buffer. These results show that both pH and crosslinking ion influence hydrogel strength and cell behaviour.

Freeze-drying is a well-established process in biomedical engineering for the fabrication of three-dimensional open-porous medical devices, especially those based on biopolymers. One of the most used biopolymers in this field is collagen, the most abundant protein in the human body and the main component of the extracellular-matrix, as well as its derivatives. Freeze-dried collagen-based sponges with a wide variety of attributes can be produced by design and have led to a wide range of successful commercial medical devices, foremost for dental, orthopedic, hemostatic and neuronal applications. However, this is still considered a high-cost and time-consuming process that is often used in a non-optimized manner. By combining advances in other technological fields, the opportunity arises to further evolve this process in a sustainable manner, and optimize the resulting products as well as create new opportunities in this field.

Developing novel wound dressings containing medicinal plant extracts can have several potential benefits, including improving the therapeutic value of the dressings and reducing the cost of producing wound dressings. In this study, we prepared foam dressing containing Eclipta prostrata leaf extract and gelatin (Eclipta prostrata dressing). Chemical composition was verified using Fourier transform infrared spectroscopy (FTIR), and pore structure was obtained by scanning electron microscopy (SEM). The physical properties, including absorption and dehydration properties, were also evaluated. The chemical properties were measured to determine the pH environment after being submerged with Eclipta prostrata dressings. The results revealed that the Eclipta prostrata dressing had a pore structure with an appropriate pore size (313.25 ± 76.51 µm and 383.26 ± 64.45 µm for the Eclipta prostrata A and Eclipta prostrata B dressings, respectively). The Eclipta prostrata B dressing was more consistent porosity, resulting in a higher absorption capacity and faster dehydration rate. According to physical properties, the Eclipta prostrata B dressing is best used on low-exuding wounds. Furthermore, the Eclipta prostrata A and B dressings make a slightly acidic environment. Therefore, our foam dressing will not interfere wound healing process.

Tissue engineering and regenerative medicine has gradually evolved as a promising therapeutic strategy to the modern healthcare of the aging and diseased population. In this study, we developed a novel nano-fibrous scaffold and verified its application in the critical bone defect regeneration. The metformin-incorporated nano-gelatin/hydroxyapatite fibers (NGF) was produced by electrospinning, cross-linked, and then characterized by XRD and FTIR. Cytotoxicity, cells adhesion, cell differentiation, and quantitative osteogenic gene and protein expression were analyzed by bone marrow stem cells from rat. Rat forearm critical bone defect model was performed for the in vivo study. The nano-gelatin/hydroxyapatite fibers (NGF) were characterized by their porous structures with proper interconnectivity without significant cytotoxic effects; the adhesion of bone marrow stem cells on the nano-gelatin/hydroxyapatite fibers (NGF) could be enhanced. The osteogenic gene and protein expression were upregulated. Post implantation, the new regenerated bone in bone defect was well demonstrated in the NGF samples. We demonstrated that the metformin-incorporated nano-gelatin-hydroxyapatite fibers greatly improved healing potential on the critical sized bone defect. Although metformin-incorporated nano-gelatin/hydroxyapatite fibers had advantageous effectiveness during bone regeneration, further validation is required before it can be applied to clinical applications.

Water pollution, driven largely by the discharge of organic dyes from various industrial processes, presents a grave environmental threat. This study delves into the promise of an innovative adsorptive composite material composed of chitosan and activated charcoal, offering a sustainable and efficient solution for removing methylene blue (MB) dye from water sources. Our comprehensive investigation encompasses the synthesis, characterization, and adsorption capabilities of this composite material, revealing its remarkable physicochemical attributes and its substantial capacity to adsorb MB dye. These findings establish it as a compelling candidate for water treatment applications. The assessment of adsorbent dosage shows a direct correlation between higher dosages and enhanced MB dye removal, with an optimal dosage determined at 0.4 g/25 mL. Furthermore, pH-dependent studies demonstrate exceptional performance at lower pH levels, achieving an impressive 95% removal rate at pH 3 after 240 minutes of contact time. The composite exhibits consistent high removal percentages across a wide range of MB dye concentrations, showcasing its adaptability. In terms of reaction time, the composite achieves peak adsorption capacity within the initial 360 minutes and maintains a stable equilibrium, sustaining an impressive 99% removal efficiency thereafter. This study underscores the eco-friendliness and cost-effectiveness of the composite material, emphasizing its potential to address water pollution challenges and promote sustainable water resource management. Overall, this research yields valuable insights into a practical approach for mitigating the adverse impact of organic dyes on aquatic ecosystems and public health.

Enzyme immobilization is known to enhance polypeptide resistance towards environmental changes, particularly in terms of their stability. The Y509E mutant of β-xylosidase from Geobacil-lus stearothermophilus (XynB2Y509E) (which also bears xylanase activity) has been immobilized in chitosan spheres through either entrapment or covalent bond formation methods. In the immo-bilization by entrapment, besides observing a total loss of xylanase activity, it was found that chitosan concentration affects the process efficiency. Additionally, the maturation time of the spheres and the alkaline pH used to precipitate the spheres affect the β-xylosidase activity of the enzyme. In covalent bond immobilization, it was found that the pH during the modification with glutaraldehyde, as well as the subsequent protein binding, were key factors in preserving the dual enzymatic activity. The activity expressed after immobilization by covalent bonding was 23% higher compared to the activity expressed following entrapment immobilization, with values of 122.3 and 99.4 U. g-1, respectively. Both biocatalysts showed increased thermal and pH stability, along with an improved storage capacity, as they retained 40% and 88% of their activi-ty after being stored at 4 C for two months. Moreover, XynB2Y509E immobilized by covalent binding also exhibited outstanding reusability, retaining a 92% of activity after ten cycles of re-use.

Chitosan is a biopolymer derived from chitin. It is a non-toxic, biocompatible, bioactive, and biodegradable polymer. Due to its properties, chitosan has found applications in several and different fields such as agriculture, food industry, medicine, paper fabrication, textile industry, and water treatment. In addition to these properties, chitosan has a good film-forming ability which allows it to be widely used for the development of sensors and biosensors. This review is focused on the use of chitosan for the formulation of electrochemical chemosensors. It also aims to provide an overview of the advantages of using chitosan as an immobilization platform for biomolecules by highlighting its applications in electrochemical biosensors. Finally, applications of electro-chemical chitosan-based chemosensors and biosensors in food safety are illustrated

Silybum marianum (L.) Gaertn is a rich source of antioxidants and anti-inflammatory flavonolignans with great potential for use in pharmaceutical and cosmetic products. Its biotechnological production using in vitro culture system has been proposed. Chitosan is a well-known elicitor that strongly affects both secondary metabolites and biomass production by plants. The effect of chitosan on S. marianum cell suspension is not known yet. In the present study, suspension cultures of S marianum were exploited for their in vitro potency to produce bioactive flavonolignans in the presence of chitosan. Established cell suspension culture was maintained on the same hormonal media supplemented with 0.5 mg/L BAP (6-benzylaminopurine) and 1.0 mg/L NAA (α-naphthalene acetic acid) under photoperiod 16/8 h (light/dark) and exposed to various treatments of chitosan (ranging from 0.5 to 50.0 mg/L). The highest biomass production was observed for cell suspension treated with 5.0 mg/L chitosan, resulting in 123.3 g/L fresh weight (FW) and 17.7 g/L dry weight (DW) productions. Chitosan treatment resulted in an overall increase in the accumulation of flavonoids, phenolic compounds and silymarin. High accumulation levels of silybin B, silydianin and silybin A were recorded by HPLC analysis. The corresponding extracts displayed interesting antioxidant and anti-inflammatory capacities. In particular, high ABTS antioxidant activity (741.5 μM Trolox C equivalent antioxidant capacity) was recorded in extracts obtained in presence of 0.5 mg/L of chitosan. On the opposite, highest inhibitions of cyclooxygenase 2 (COX-2, 30.5 %), secretory phospholipase A2 (sPLA2, 33.9 %) and 15-lipoxygenase (15-LOX-2, 31.6 %) enzymes involved in inflammation process were measured in extracts obtained in presence of 5.0 mg/L of chitosan. Taken together, these results highlight the high potential of the chitosan elicitation of the S. marianum cell suspension for enhanced production of antioxidant and anti-inflammatory silymarin-rich extracts.

This study presents a meta-analysis of studies that investigate the effectiveness of chitosan administration on lifestyle-related disease in murine models. A total of 34 published studies were used to evaluate the effect of chitosan supplementation. The effect sizes for various items after chitosan administration were evaluated using the standardized mean difference. Using Cochran’s Q test, the heterogeneity of effect sizes was assessed, after which a meta-ANOVA and –regression test was conducted to explain the heterogeneity of effect sizes using the mixed-effect model. Publication bias was performed using Egger’s linear regression test. Among the items evaluated, blood triglyceride and HDL-cholesterol showed the highest Q statistics and I2 values, respectively. Other than blood HDL-cholesterol, total cholesterol, and triglyceride in feces, most items evaluated showed a negative effect size with high significance in the fixed- and random-effect model (p<0.0001). In the meta-ANOVA and -regression test, administering chitosan and resistant starch was revealed to be most effective in lowering body weight. In addition, chitosan supplementation proved to be an effective solution for TNF-α inhibition. In conclusion, chitosan has been shown to be somewhat useful in improving symptoms of lifestyle-related disease. Although there are some limitations in the results of this meta-analysis due to the limited number of animal experiments conducted, chitosan administration nevertheless shows promise in enhancing the quality of human life.

In this study, silver-strontium doped hydroxyapatite (AgSr-HA)/chitosan composite coatings were deposited on stainless steel (SS) substrate via electrophoretic deposition (EPD) technique. The EPD parameters such as the concentration of Ag Sr-HA particles in the suspension, applied voltage and deposition time were optimized on by the Taguchi Design of Experiment (DoE) approach. DOE approach elucidated that the “best” coating was obtained at; the deposition voltage of 20V, deposition time of 7 minutes, and at 5 g/L of Ag Sr-HA particles in the suspension. The optimum coatings were characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. SEM images confirmed the deposition of chitosan/Ag Sr-HA on the SS substrate. The wettability studies indicated the hydrophilic nature of the chitosan/Ag Sr-HA coatings, which confirmed the suitability of the developed coatings for orthopedic applications. The average surface roughness of the chitosan/Ag Sr-HA coatings was in a suitable range for the attachment of bone marrow stromal cells. Chitosan/Ag Sr-HA coatings showed a potent antibacterial effect against the Gram-Positive and Gram-negative bacteria.

New approaches to deal with drug-resistant pathogenic bacteria are urgent. We studied the antibacterial effect of chitosans against an E. coli quorum sensing biosensor reporter strain, and selected a non-toxic chitosan to evaluate its QS inhibition activity and its effect on bacterial aggregation. To this end, chitosans of varying DA (12 to 69%) and M_w (29 to 288 KDa) were studied. Only chitosans of low DA (~12%) inhibited the bacterial growth, regardless of the M_w. Chitosan MDP DA30 (DA 42% and M_w 115 kDa) was selected for further QS inhibition and SEM imaging studies. MDP DA30 chitosan exhibited QS inhibition activity in an inverse dose-dependent manner (≤12.5 µg/mL). SEM images revealed that this chitosan, when added at low concentration (≤30.6 µg/mL), induced substantial bacterial aggregation, whereas at high concentration (234.3 µg/mL), it did not. Aggregation explains the QS inhibition activity as the consequence of retardation of the diffusion of AHL.

The aim of this work is to develop a method to produce spherical biopolymer-based aerogel particles, which is capable for scale up in the future. Therefore, jet cutting method is suggested. Amidated pectin and sodium alginate were used as precursor (1–3 wt. % solution) for particle production via jet cutting. Gelation was realized via two methods: internal setting method (using calcium carbonate particles as cross-linker and citric and acidic acid for pH adjustment) and diffusion method (in calcium chloride solutions). Gel particles were subjected to solvent exchange to ethanol and consequent supercritical drying with CO₂. Spherical aerogel particles with narrow particle size distribution in the range of 400 to 1500 µm and with specific surface area of around 500 m²/g could be produced. Overall, it can be concluded that jet cutting method is suitable for aerogel particle production, although the shape of the particles is not perfectly spherical in all cases. However, parameter adjustment might lead to even better shaped particles in further work. Moreover, the biopolymer-based aerogel particles synthesized in this study were tested as humidity absorber in drying units for home appliances, particularly for dishwashers. It could be shown that for several cycles of absorption and desorption of humidity aerogel particles are stable with an absorption capacity of around 20 wt. %.

Encapsulation of antioxidant polyphenols leads to increase solubility and bioavailability of these micronutrients in solution. The encapsulation of antioxidant resveratrol, genistein and curcumin by folic acid-chitosan nanocapsules was studied in aqueous solution, using multiple spectroscopic methods, TEM images. Structural analysis showed that polyphenol bindings are via hydrophilic, hydrophobic and H-bonding contacts with resveratrol forming more stable conjugates. As chitosan size increased, the binding efficacy and stability of polyphenol-polymer adducts were increased. Polyphenol binding induced major alterations of chitosan morphology. Chitosan nanoparticles are capable of delivery of polyphenols in vitro.

Photodynamic inactivation (PDI) combines the nontoxic photosensitizer (PS) and visible light to generate reactive oxygen species (ROS), which can cause oxidative damages in (on) microbial organisms. Previously, we have shown that chitosan can augment the bactericidal efficacy mediated by PDI against bacteria and Candida. In this study, we showed that the antimicrobial action of chitosan to augment PDI relates to the enlargement of cell surface destruction. The microbial cell surfaces exhibit severe irregular shapes after PDI in the presence of chitosan. Furthermore, increase in the concentrations or incubation time of chitosan significantly reduce the amounts of photosensitizers TBO required, indicating that chitosan could be a synergistic agent with PDI against human pathogens. A prolonged lag phase was found in PDI surviving microbial cells, in which chitosan can act to synergistically eradicate the cells. Once the impaired cells rebuild their cellular functions from PDI-induced damage, the increased cytotoxic effect of chitosan disappeared. Together, our results suggest that chitosan with an augmented bactericidal activity after PDI is to inhibit the rehabilitation of PDI surviving cells, leading to microbial death.

Chitosan is a cationic polysaccharide usually obtained by alkaline deacetylation of chitin poly(N-acetylglucosamine). It is biocompatible, biodegradable, mucoadhesive and non-toxic. These excellent biological properties make chitosan a good candidate for a platform in developing drug delivery systems having improved biodistribution, increased specificity and sensitivity, and reduced pharmacological toxicity. In particular, chitosan nanoparticles are found to be appropriate for non-invasive routes of drug administration: oral, nasal, pulmonary and ocular routes. These applications are facilitated by the absorption-enhancing effect of chitosan. Many procedures for obtaining chitosan nanoparticles have been proposed. Particularly, the introduction of hydrophobic moieties into chitosan molecules by grafting to generate a hydrophobic-hydrophilic balance promoting self-assembly is a current and appealing approach. The grafting agent can be a hydrophobic moiety forming micelles that can entrap lipophilic drugs or it can be the drug itself. Another suitable way to generate self-assembled chitosan nanoparticles is through the formation of polyelectrolyte complexes with polyanions. This paper reviews the main approaches for preparing chitosan nanoparticles by self-assembly through both procedures and illustrates the state of the art of their application in drug delivery.

The synthesis of new collagen, chitosan and chitosan-collagen coated magnetic nanoparticles have been done. Two types of cross-linkers for polymer shell stabilization were used: glutaraldehyde (Gla) as a standard cross-linker and new one – squaric acid (SqA). Structure and morphology of prepared nanoparticles were characterized by ATR-FT IR, XRD and TEM analysis. The immobilization of lipase from Candida rugosa was performed on the nanoparticles surface. The amount of immobilized enzyme was quantified by the Bradford method. All of lipase-biopolymers coated nanoparticles were characterized with good activity recovery. A little hyperactivation of lipase immobilized on nanoparticles with SqA was observed. All of prepared lipase-immobilized nanoparticles were characterized with very good reusability.

Infectious diabetic wounds can result in severe injuries or even death. Biocompatible wound dressings offer one of the best ways to treat these wounds, but creating a dressing with suitable hydrophilicity and biodegradation rate can be challenging. To address this issue, we used the electrospinning method to create a wound dressing composed of poly(glycerol sebacate) (PGS) and gelatin (Gel). We dissolved the PGS and Gel in acetic acid (75 v/v%) and added EDC/NHS solution as a crosslinking agent. Our measurements revealed that the scaffolds' fiber diameter ranged from 180.2 to 370.6 nm, and all the scaffolds had porosity percentages above 70%, making them suitable for wound healing applications. Additionally, we observed a significant decrease (p &lt; 0.05) in the contact angle from 110.8° ± 4.3° for PGS to 54.9° ± 2.1° for PGS/Gel scaffolds, indicating an improvement in hydrophilicity of the blend scaffold. Furthermore, our cell viability evaluations demonstrated a significant increase (p &lt; 0.05) in cultured cell growth and proliferation on the scaffolds during the culture time. Our findings suggest that the PGS/Gel scaffold has potential for wound healing applications.

Background: Multiple drug delivery systems obtained by loading nanoparticles (NPs) with different drugs with different physicochemical properties present a promising strategy to achieve synergistic effects between drugs or overcome undesired effects. This study aims to develop a new NP by loading Quercetin (Que) and valproic acid (VPA) onto chitosan. In this context, our study investigated the antioxidant activities of chitosan NPs loaded with single and dual drugs containing Que against oxidative stress. Method: The synthesis of single (Que or VPA) and dual-drug (Que and VPA) loaded chitosan NPs, characterization of the NPs, conducting in vitro antioxidant activity studies, and analysis of the cytotoxicity and antioxidant activity of the NPs in SH-SY5Y cell lines were performed. Result: The NP applications that protected cell viability to the greatest extent against H2O2-induced cell damage were, respectively, 96 µg/ml of Que-loaded chitosan NP (77.30%, 48 h), 2 µg/ml of VPA-loaded chitosan NP (70.06%, 24 h), 96 µg/ml of blank chitosan NP (68.31%, 48 h), and 2 µg/ml of Que and VPA-loaded chitosan NP (66.03%, 24 h). Conclusion: Our study establishes a successful paradigm in developing drug-loaded NPs, with uniform and homogeneous distribution of drugs onto NPs. Chitosan NPs loaded with both single and dual drugs possessing antioxidant activity were successfully developed.

The suspension cross-linking technique has been utilized to create the magnetic chitosan nanoparticles, which were then applied to the magnetic carrier method at 80°C. First the FeCl2 and FeCl3 solution co-precipitated and synthesized Fe3O4 for utilization in the formation of magnetic chitosan nanoparticles, it has been characterized by utilizing DLS (Dynamic light scattering), XRD (X-ray diffraction spectrometer), FTIR (Fourier transform infrared spectroscopy), which identified structure, size, FE-SEM (Field Emission Scanning Electron Microscope) and HR-TEM (High-resolution transmission electron microscopy) which identified structure and particle size whereas magnetic behavior of chitosan nanoparticles was determined by VSM (Vibrating sample magnetometer). According to the results collected, the magnetic chitosan nanoparticles have been spherical in form and size ranging from around 250 to 400 nm.

Agaricus bisporus is well known as a source of polysaccharides that could improve human health. The objective of this study was to explore anti-obesity effect of A. bisporus extract (H2Oslim®) abundant in polysaccharides and its underlying mechanism. Pancreatic lipase inhibitory activity in vitro was determined after treatment with H2Oslim® and chitosan. Treatment with H2Oslim® and chitosan significantly decreased pancreatic lipase activity. Five-week-old male SD rats were randomly divided into three groups for acute feeding with vehicle, H2Oslim® at 80 mg/kg body weight (BW)/day, and H2Oslim® at 160 mg/kg BW/day. H2Oslim® does-dependently increased plasma lipid clearance in an oral lipid tolerance test. Five-week-old male C57BL/6N mice were fed a control diet (CD), a high fat diet (HFD), an HFD with H2Oslim® at 80 mg/kg BW/day, H2Oslim® at 160 mg/kg BW/day, or chitosan at 160 mg/kg BW/day for eight weeks. HFD-fed mice showed significant increases of body weight, fat mass, white adipose tissue, average lipid droplet size, and serum levels of glucose, triglyceride, ALT, and AST compared to those in the CD group. However, H2Oslim® or chitosan administration ameliorated these increases. H2Oslim® or chitosan signifi-cantly reduced dietary efficiency and increased fecal excretion levels of lipid, triglyceride, and total cholesterol. These in vitro and in vivo findings suggest that H2Oslim® might act as an anti-obesity agent by inhibiting pancreatic lipase-mediated lipid absorption, at least in part.

The present study produced and characterised chitosan, chitosan nanoparticle, chitosan n – benzaldehyde Schiff base, chitosan nanoparticle n – benzaldehyde Schiff base, Fe(III) chitosan n – benzaldehyde Schiff base and Fe(III) chitosan nanoparticle n – benzaldehyde Schiff base for biomedical application as antimicrobial agents. The materials were characterized with Fourier Transform Infrared spectroscopy, X-ray Diffractogram and biologically evaluated using disc diffusion method with three gram-positive bacteria. The FTIR absorption peaks were shifted to a lower wave number than the micro materials from which it was modified. These clearly indicate the linkage between phosphate, ammonium ion, Schiff base and Fe(III) metal. The diffracted peaks of Fe(III) chitosan nanoparticle n – benzaldehyde Schiff base were new peaks at 2θ = 24o and 42o when compare to the peak of Fe(III) chitosan n – benzaldehyde Schiff base of 2θ = 22.5o and 34o. The difference in peak shift were attributed to the ionic bonding of the complexation of Fe(III) with the blending of benzaldehyde to chitosan – Tpp backbone structure. Fe(III) chitosan nanoparticle Schiff base has more antimicrobial activity against same bacteria and fungi tested than Fe(III) chitosan n – benzaldehyde Schiff base, chitosan n – benzaldehyde Schiff base and chitosan. The antimicrobial activities of the synthesised six materials shown that the materials have high activities than the above – mentioned standard drugs.

The purpose of this study is to identify the steps involved in fabricating silica/chitosan composite membranes and their suitability in fuel cell application. It also intends to identify the physical characteristics of chitosan composite membranes, including their degree of water absorption, proton conductivity, methanol permeability, and functional groups. In this investigation, composite membranes were fabricated using the solution casting method with chitosan content of 5 g and silica variations dosage of 2% and 4% while stirring at a constant speed for 2h. According to the findings, the analysis of composite membranes produced chitosan membranes that were successfully modified with silica. The optimum membrane was found to be 4% s-SiO2 from the Sol-gel method with composite membrane's optimal condition of 0.234 cm/s proton conductivity, water uptake of 56.21%, and reduced methanol permeability of 0.99 × 10 -7 cm2/s in the first 30 minutes and 3.31 × 10-7 in the last 150 minutes. Maintaining lower water uptake capacity at higher silica content is still a challenge that needs to be addressed. However, the fabricated membranes showed exceptional results in terms of proton conductivity and methanol permeability.

This study revealed the synthesis of cross-linked chitosan/Citrus reticulata peel waste (C/CRPW) composites that could be used as low-cost and green bio-adsorbents for the removal of Congo red (CR) dye from aqueous solutions. C/CRPW composites containing different amounts of Citrus reticulata peel waste (CRPW) and chitosan were prepared and cross-linked with glutaraldehyde. The composites were characterized by FESEM, FTIR, and BET. The C/CRPW composites as a new type of bio-adsorbents displayed superior adsorption capability toward anionic CR molecules and the adsorption capacities increased by incorporation of CRPW. Effects of different ambient conditions such as contact time, pH, adsorbent dosage, initial adsorbate concentration, and temperature were fully studied. The conditions which obtained 43.57 mg/g of the highest adsorption capacity were conducted at pH 4, initial concentration of 100 mg/L, adsorbent dosage of 2.0 g/L, and contact time of 24 hours at 328 K. The adsorption data was found to follow the pseudo-second-order kinetic model and the Freundlich isotherm model. According to the findings of this investigation, it was observed that the C/CRWP composites can be used as adsorbents due to their advantages of simple preparation process, environmentally friendly, renewable, efficient, and low-cost.

The influence of pH, temperature, biopolymer ratio, total concentration, and ionic concentration on the interaction between egg white protein (EWP) and chitosan (CS) was investigated through turbidity, zeta potential, and state diagram in our research. In addition, phase behavior was observed under various conditions. The turbidity of EWP remained low (turbidity&lt;0.03) and basically unchanged at a wide range of pH (4.0-8.0), while the turbidity of CS was slightly higher (turbidity&lt;0.2) after pH 7.0 than before. Moreover, under the same conditions, a sharply rising peak pattern was observed for the complex between EWP and CS. The maximum turbidity value was observed at 55°C, and the temperature had a mild effect on turbidity. The optimum EWP to CS ratio was found to be 12:1 based on the experiment of the turbidity curves and state diagrams influenced by different biopolymer mixing ratios. With the enhanced concentrations of total biopolymer, the maximum turbidity rose insignificantly above 0.1%.

Green microalgae including those from the genus Lobosphaera are exploited in biotechnology to obtain valuable fatty acids e.g., arachidonic acid (C20:4, ARA) for the production of infant formulae, food and feed additives. In nature, microalgae frequently exist in naturally immobilized state (as biofilms) with limited cell division rate and increased stress resilience. In biotechnology, immobilization of microalgae on artificial cell carriers simplifies biomass harvesting, increases culture robustness and productivity. The choice of suitable cell carrier is central to biotechnology of immobilized culture. Cell carriers based on the natural amine-containing polymer chitosan and synthetic polyethylenimine (PEI) are promising candidates for immobilization of phototrophic microorganisms. This is the first report on the effects of immobilization on PEI and chitosan on the accumulation and composition of polyunsaturated fatty acids, including ARA, in Lobosphaera sp. IPPAS C-2047. The immobilization on PEI increased ARA percentage in the total tatty acids and ARA accumulation by 72% and 81%, compared with the suspended cells cultured respectively in complete or nitrogen-deprived medium 14 days. Immobilization of Lobosphaera sp. on the chitosan-based carrier declined ARA but increased oleic and α-linoleic acid percentages. Mechanisms of the effects of immobilization on fatty acid profiles of the microalgae are discussed.

Active films based on carboxymethyl chitosan incorporated corn peptide were developed. Physicochemical properties of the films, including thickness, opacity, moisture content, color, mechanical properties, water vapor permeability, and oil resistance, were measured. Biological activities of the films, including the antioxidant and antibacterial activities, were characterized in terms of 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging activity, reducing power, the total antioxidant activity, and the filter disc inhibition zone method. The results indicated that the incorporation of corn peptide caused interactions between carboxymethyl chitosan and corn peptide in Maillard reaction and gave rise to the films light yellow appearance. Compared with the Control, the degree of glycosylation, browning intensity, thickness, opacity, tensile strength, antioxidant activity, and antibacterial activity of films were increased, but the elongation, vapor permeability, and oil resistance of films were decreased. The films based on corn peptide and carboxymethyl chitosan can potentially be applied to food packaging.

Scaffolds are widely used in tissue engineering because their manufacture is based on natural and synthetic polymers, which allows them to have properties such as biocompatibility and biodegradability, creating an ideal environment for cell growth on their surface. In this context, among the polymers studied in Tissue Engineering are Chitosan (CH) and Polyvinyl Alcohol (PVA). CH is a versatile polymer obtained from de-acetylation of chitin, which is used for its high biodegradability and biocompatibility, although its mechanical properties must be improved. It has been found that one of the ways to improve the mechanical properties of CH is to mix it with other synthetic polymers such as PVA. PVA is known for its biocompatibility, biodegradability, zero toxicity and ease of preparation due to its solubility in water and excellent mechanical properties, such as tensile strength and ease in the formation of films and barriers. In this study we evaluated the capacity of scaffolds made with CH and PVA in different concentrations (2: 1, 1: 1, 1: 2, respectively) as a possible application in bone regeneration. This was made through different characterization tests such as Infrared Spectroscopy, AFM, Swelling test and Porosity test, where we obtained information about its structural and physicochemical properties. Additionally, a cellular quality control was performed on the material through the MTT assay. The Fourier transform infrared spectroscopy (FTIR) study showed that there are strong intermolecular hydrogen bonds between the chitosan and polyvinyl alcohol molecules. The Swelling and Porosity tests showed favorable results, obtaining maximum values ​​of 5519% and 72.17% respectively. MTT tests determined that the prepared materials are not cytotoxic. These findings suggest that scaffolds possess properties suitable for use in Tissue Engineering.

The recovery and valorization of waste are some of the key aspects of sustainable production. The crustacean exoskeletons can be potentially used to obtain value-added products such as chitosan. A comprehensive analysis including both safety and sustainability aspects of chitosan production from shrimp shells is presented in this study. The inherent safety analysis and sustainability evaluation was performed using the Inherent Safety Index (ISI) methodology and the Sustainable Weighted Return on Investment Metric (SWROIM), respectively. The process was designed for a processing capacity of 57,000 t/y according to shrimp production in Colombia. The economic (%ROI), environmental (PEI output), energy (exergy efficiency), and safety (ITI) technical parameters were included in the sustainability evaluation. The three first were obtained from the previous analysis performed by the authors. The total inherent safety index was estimated at 25 indicating that the process is inherently unsafe. The main process risks were given by the dangerous substance, reactivity, and inventory subindices. The overall sustainability evaluation showed a SWROIM of 36.23% indicating that the case study showed higher weighted performance compared to the return on investment (ROI) metric of 18.08%.

The purpose of this study was to investigate the effect of chitosan (CS) and Alginate (Alg) polymers concentrations and CaCl2 concentration on metronidazole (MET) drug loading (LE), size particles and zeta potential. Nanocomposites were prepared by ionotropic pregelation method. A (21 *31 *21) *3= 36 full factorial design (FFD) was used to predict statistical equation and responses. The MET-CS-AlgNPs nanocomposites were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscope and in vitro drug release studies. All data indicated the presence of drug into MET-CS-AlgNPs nanocomposites. The release profile of MET-CS-AlgNPs nanocomposites was found to be sustained

Electrospinning is the versatile technique to generate large quantities of micro- or nano-fibers from a wide variety of shapes and sizes of polymer. Natural bone is a hierarchically composites with the dispersion of inorganic ceramic along organic polymer. The aim of this study, the electrospun poly (lactic acid) (PLA) mats coated with chitosan (CH) and calcium silicate (CS) powder were fabricated. The morphology, chemical composition, and surface properties of CS/CH-PLA composites were characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. In vitro, the CS/CH-coated PLA mats increased the formation of apatite on the surface when soaking in cell cultured medium. During culture, the adhesion and proliferation of the human mesenchymal stem cells (hMSCs) cultured on CS/CH-PLA were significantly promoted relative to those on PLA. Collagen I and fibronectin levels and promoted cell adhesion were observed upon an increase in CS content. Further, compared to PLA mats without CS/CH, CS10 and CS15 mats markedly enhanced the proliferation of hMSCs as well as their osteogenesis properties, which was characterized by bone-related gene expression. Our results demonstrated that the biodegradable and electroactive CS/CH-PLA mats had potential application as an ideal candidate for bone tissue engineering. Together, findings from this study clearly demonstrated that PLLA-C2S composite scaffold may function as an ideal candidate for bone tissue engineering.

Background: Antibiotic-containing carrier systems are one option that offers the advantage of releasing active ingredients over a longer period of time. In vitro sustained drug release from a carrier system consisting of microporous β-TCP ceramic and alginate has been reported in previous works. Alginate dialdehyde (ADA) gelatin gel showed both better mechanical properties when loaded into a β-TCP ceramic and higher biodegradability than pure alginate. Methods: Dual release of daptomycin and BMP-2 was measured on days 1, 2, 3, 6, 9, 14, 21, and 28 by HPLC and ELISA. After release, the microbial efficacy of the daptomycin was verified and the biocompatibility of the composite was tested in cell culture. Results: Daptomycin and the model compound FITC protein A (n=30) were released from the composite over 28 days. A Daptomycin release above the minimum inhibitory concentration (MIC) by day 9 and a burst release of 71.7 ± 5.9 % were observed in the loaded ceramics. Low concentrations of BMP-2 were released from the loaded ceramics over 28 days.

Fibroin-chitosan composites, especially those containing nanohydroxyapatite, show potential for bone tissue regeneration. The physicochemical properties of these biocomposites depend on the compatibility between their components. In this study, the intermolecular interactions of fibroin and chitosan were analyzed using a molecular dynamics approach. Two types of systems were investigated: one containing acetic acid and the other containing calcium (Ca²⁺) and hydrogen phosphate (HPO₄²⁻) ions mimicking hydroxyapatite conditions. After obtaining the optimal equilibrium structures, the distributions of several types of interactions including hydrogen bonds, ionic contacts, and hydrophobic contacts along with the structural and energetical features were examined. The calculated binding energy values for the fibroin-chitosan complexes confirm their remarkable stability. The high affinity of fibroin for chitosan can be explained by the formation of a dense network of interactions between considered biopolymers. These interactions were found to be primarily hydrogen bonds and ionic contacts involving ALA, ARG, ASN, ASP, GLN, GLU, GLY, LEU, PRO, SER, THR, TYR, and VAL residues. As it was established, the complexation of fibroin with chitosan maintains the β-sheet conformation of the peptide. β-Sheet fragments in fibroin are involved in the formation of significant amount of hydrogen bonds and ionic contacts with chitosan.

Silk fibroin (SF) extracted from Bombyx mori cocoons is a biocompatible and biodegradable polymer shows potential as matrices for tissue engineering and regenerative medicine, or con-trolled drug delivery systems. Regenerated fibroin, obtained by removing sericin from natural silk, is water-soluble. Its aqueous solutions can be processed into a variety of materials, for example, fibrous matrices, using the electrospinning method. In this article, the concentration dependences of the properties of aqueous solutions of regener-ated fibroin, that determine the possibility of obtaining electrospun mats for tissue-engineering applications, are studied. A slowdown in the growth of viscosity after a concentration of fibroin of 30% and a decrease in the transparency of the solution were found; this may be due to the on-set of conformational rearrangements: the transition of fibroin from the random coils, charac-teristic for dilute solutions, to the anisotropic conformation of the helix and the appearance of β-pleated sheets. Fibrous mats from regenerated fibroin were obtained from solutions with a concentration of 10 and 20%. Two methods were used to prevent solubility of fibroin-based matrices: conversion of fibroin to the β-conformation by treatment with an ethanol solution and chemical cross-linking with gen-ipin (Gp). The structures of the fibrous samples were studied by AFM and confocal laser scan-ning microscopy. The composition of the moulding solution for the electrospinning of regener-ated fibroin fibrous matrices and the conditions for their modification have been optimised. It has been shown that the composition of fibroin with chitosan contributes to a decrease in the solubility of electrospun fibrous matrices by increasing the number of amino groups available for modification by Gp, and also leads to a decrease in the diameter of the fibers. Electrospun fiber matrices based on regenerated SF, modified by cross-linking with Gp in water-alcohol solutions, promote cell growth and proliferation and may be promising for tissue engineering.

Hemorrhage is a detrimental event present in traumatic injury, surgery, and disorders of bleeding, that can become life-threatening if not properly managed. Moreover, uncontrolled bleeding can complicate surgical interventions, altering the outcome of surgical procedures. Therefore, to reduce the risk of complications and decrease the risk of morbidity and mortality associated with hemorrhage, it is necessary to use an effective hemostatic agent that ensures immediate control of bleeding. In recent years, there have been increasingly rapid advances in developing novel generation of biomaterials with hemostatic properties. Nowadays, a wide array of topical hemostatic agents is available, including chitosan-based biomaterials that have shown outstanding properties such as: antibacterial, antifungal, hemostatic, analgesic activity, in addition to their biocompatibility, biodegradability, and wound-healing effects. This review provides an analysis of chitosan-based hemostatic and discusses the progress made in their performance, mechanism of action, efficacy, cost, and safety in recent years.

Potato tubers are susceptible to wounding during post-harvest processes, leading to quality decline, perishability and large economic losses. In this study, the potato cultivar, ‘Longshu No.7’, was foliar-sprayed with 3% chitosan (w/v) three times during the pre-harvest period after flowering to evaluate the effect of foliar spraying with chitosan on suberization processing at wounds of harvested potato tubers. Our results demonstrate that foliar-sprayed with chitosan significantly reduced wound-induced fresh weight loss and dry rot disease index by 37.34% and 41.60% on the 28 day after wounding, respectively. Foliar-sprayed with chitosan accelerated the deposition of suberin polyphenolics and lignin at the wound sites of potato tubers with the formation of thicker cell layers. This occurred with increased localized activities of key enzymes in the suberin polyphenolics and lignin pathways, including phenylalanine ammonia lyase, 4-coumaryl-coenzyme A ligase, cinnamyl alcohol dehydrogenase and peroxidase (33.90–64.32%), as well as the contents of cinnamic acid, sinapic acid, flavonoids, lignins and total phenolics (19.70–23.46%) at wound sites of potato tubers on the 7 day after wounding. Our results indicated that foliar application of chitosan accelerated wound-induced suberization of potato tubers and could mitigate post-harvest product damages.

Abstract The present work was designed to investigate antiviral potential of novel mono and oligomeric Chitosan derivatives through in-silico approaches to find potent broad-spectrum anti-viral and promising drug candidates against SARS-CoV-2 and augmentation of their mode of action. Chitosan biopolymer and its derivatives were screened virtually against spike glycoprotein and human ACE2 receptor of nCoV-19. HTCC a polymeric Chitosan has been reported to interact with the corona viral Spike (S) protein and blocks its interaction with ACE2 receptor. Better biocompatibility, structural correlations, variation in degree of decetylation and molecular weight of modified Chitosan derivatives are the key attributes for enhancement of anti-viral activity. The Chitosan derivatives constructively interact with viral S protein. N-Carboxy methyl Chitosan (NCMC) among the Chitosan derivatives displayed efficient binding affinity. NCMC, when compared to mHTCC, a monomeric Chitosan for its interaction with the S protein, RBD site and ACE2 receptor, displayed efficient binding affinity with binding energy of -7.9, -6.3 and -7.4; -6.2, -4.8 and -5.5 Kcal/mol respectively. The interaction of S protein with ACE2 and ligand mHTCC-S protein complex and NCMC-S protein complex with ACE2 was calculated through flexible docking resulted in efficient reduction of binding energy from -901.2kJ/mol to -765.06kJ/mol and-814.72kJ/mol respectively, elucidated that the binding affinity of the viral S protein for its receptor ACE2 decreases in the presence of NCMC/mHTCC. The computational study envisages the antiviral efficiency of NCMC, mHTCC and biocompatible Chitosan derivatives for the first time,as preventive intervention against Covid-19.

Starch is a biopolymer with wide potential for the generation of new biodegradable packages due to its high availability and low price. However, due to its weak functional properties, it is necessary to limit the interaction of some hydroxyl, and to evaluate blends with other polymers to improve their performance. Glycerol plasticized acetylated corn starch films were developed by the casting method, and the impact of incorporating chitosan (TPS:CH) at various proportions (75:25, 50:50, and 25:75 v/v) was studied. The effect of the chitosan ratios on the films' physical, mechanical, water vapor barrier, and thermal properties was evaluated. Chitosan protonated amino groups promote the formation of intermolecular bonds, improving the tensile strength, the thermal stability, the water adsorption capacity, and the gas barrier of starch films. Where the film composed of TPS25-CH75 was the one that presented the best barrier to water vapor. These composite films are a good option for development of biodegradable packaging.

Chitosan arouses large interest due to its properties and possible applications. Every year the number of publications and patents based on this polymer increases. Chitosan exhibits poor solubility in neutral and basic media limiting its use in such conditions. Another serious obstacle is directly related to its natural origin. Chitosan is not a single polymer with a defined structure but a family of molecules with differences in their composition, size, and monomer distribution. These properties have a fundamental effect on the biological and technological performance of the polymer. Moreover, some of the biological properties claimed are discrete. In this review, we discuss how chitosan chemistry can solve the problems related to its poor solubility and can boost the polymer properties. We focus on some of the main biological properties of chitosan and the relationship with the physicochemical properties of the polymer. Then, we visit two polymer applications related to green processes: the use of chitosan in the green synthesis of metallic na-noparticles and its use as support in biocatalyst. Finally, we briefly describe how making use of the technological properties of chitosan it is possible to develop a variety of systems for drug delivery

In this work, we designed and fabricated a multifunctional nanocomposite system which consists of chitosan, raspberry-like silver nanoparticles and graphene oxide. Room temperature atmospheric pressure microplasma (RT-APM) process provides a rapid, facile, and environment-friendly method for introducing silver nanoparticles into the composite system. By loading different drugs onto the polymer matrix and/or graphene oxide, our composite can achieve a pH controlled dual drug release with release profile specific to the drugs used. In addition to its strong antibacterial ability against E. coli and S. aureus, our composite also demonstrates excellent photothermal conversion effect under irradiation of near infrared lasers. These unique functionalities point to it’s the potential of nanocomposite system in multiple applications areas such as multimodal therapeutics in healthcare, water treatment, and anti-microbial, etc.