One-dimensional nanostructures such as silver nanowires (AgNWs) have attracted considerable attention owing to their outstanding electrical, thermal and antimicrobial properties; however, their application in the prevention of infections linked to bone tissue regeneration interventions has not yet been explored. Here we report on the development of an innovative scaffold prepared from chitosan, composite hydroxyapatite and AgNWs (CS-HACS-AgNWs) having both bioactive and antibacterial properties. In vitro results highlighted the antibacterial potential of AgNWs against both gram-positive and gram-negative bacteria. The CS-HACS-AgNWs composite scaffold demonstrated suitable Ca/P deposition, improved gel strength, reduced gelation time, and sustained Ag+ release within therapeutic concentrations. Antibacterial studies showed that the composite formulation was capable of inhibiting bacterial growth in suspension and of completely preventing biofilm formation on the scaffold in the presence of resistant strains. The hydrogels were also shown to be biocompatible, allowing cell proliferation. In summary, the developed CS-HACS-AgNWs composite hydrogels demonstrated significant potential as a scaffold material to be employed in bone regenerative medicine, as it presents enhanced mechanical strength combined with the ability to allow calcium salts deposition, while efficiently decreasing the risk of infections. The results presented justify further investigations into potential clinical applications of these materials.

Drug delivery to the brain represents a challenge especially in the therapy of central nervous system malignancies. Simvastatin (SVT), as other statins, has shown potential anticancer properties that are difficult to exploit in the CNS. In the present work the physico-chemical, mucoadhesive and permeability enhancing properties of simvastatin-loaded poly-ε-caprolactone nanocapsules coated with chitosan for nose-to-brain administration were investigated. Lipid-core nanocapsules coated with different molecular weight (MW) chitosans (LNCchit) prepared by a novel one-pot technique were characterized for particle size, surface charge, particle number density, morphology, drug encapsulation efficiency, interaction between surface nanocapsules with mucin, drug release and permeability across two nasal mucosa models. Results show that all formulations present adequate particle size (below 220 nm), positive surface charge, narrow droplet size distribution (PDI<0.2) and high encapsulation efficiency. Nanocapsules presented controlled drug release and mucoadhesive properties dependent on the MW of the coating chitosan. The results of permeation across RPMI 2650 human nasal cell line evidenced that LNCchit increased the permeation of SVT. In particular, the amount of SVT permeated after 4h for nanocapsules coated with low MW chitosan, high MW chitosan and control SVT was 13.91 ± 0.78 µg, 9.15 ± 1.23 µg and 1.42 ± 0.21 µg respectively. These results were confirmed by the SVT ex vivo permeation across rabbit nasal mucosa. This study highlighted the suitability of LNCchit as promising strategy for the administration of simvastatin for a nose-to-brain approach for the therapy of brain tumors.

Chitosan decorated copper nanoparticles (CS/CuNPs) catalysts were synthesized via reduction methods utilizing green protocol. The CS/CuNPs hybrid catalysts were tested for the synthesis of quinoline derivatives utilizing one-pot multicomponent reaction (MCR) under ultrasonic irradiation. The best catalyst (CS/CuNPs) that provided good conversion reaction yield and high turnover frequency (TOF) was characterized using Fourier transform infrared (FTIR), Thermogravimetric analyses (TGA), X-ray diffraction (XRD), , scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. Generalization of the scope of the proposed catalytic process was studied using different aldehydes. Excellent products yield and high TOF in even shorter reaction time (~5 min) was attained. Recyclability performance of the catalyst over five times re-use without detectable loss in product yield was recorded. The current method is green process utilizing environmentally benign catalyst and considered to be promising sustainable protocol for the synthesis of fine chemicals.

In this work, an enzymatic sensor, based on a bionanocomposite film consisting of a polyelectrolyte complex (PEC) [Chitosan/kappa-carrageenan] doped with gold nanoparticles (AuNPs) encapsulating glucose oxidase (GOD) deposited on a gold electrode (Au) for glucose sensing, is described. Using the electrocatalytic synergy of AuNPs and GOD as a model of enzyme, the variation of the current (µA) as a function of the log of the glucose concentration (log [glucose]), shows 3 times higher sensitivity for the modified electrode (283.9) compared to that of the PEC/GOD modified electrode (93.7), with a detection limit of about 5 µM and a linearity range between 10µM and 7mM. The response of the PEC/AuNPs/GOD based biosensor also presents good reproducibility, stability and negligible interfering effects from ascorbic acid, uric acid, urea and creatinine. The applicability of the PEC/AuNPs/GOD based biosensor was tested in glucose-spiked saliva samples and acceptable recovery rates were obtained.

Calorie restriction (CR) has been shown to prolong the lifespan of humans, but enforcing long-term CR is difficult. Therefore, a compound that reproduces the effect of CR without CR is needed. In this review, we summarize the current knowledge on compounds with CR mimetic (CRM) effects. More than 10 compounds have been listed as CRMs, some of which are conventionally categorized as upstream-type CRMs showing glycolytic inhibition while the others are categorized as downstream-type CRMs that regulate or genetically modulate intracellular signaling proteins. Among these, we focus on upstream-type CRMs and propose their classification as compounds with energy metabolism inhibition effects, particularly glucose metabolism modulation effects. The upstream-type CRMs reviewed include chitosan, acarbose, sodium-glucose cotransporter 2 inhibitors, and hexose analogs such as 2-deoxy-D-glucose, D-glucosamine, and D-allulose, which show anti-aging and longevity effects. Finally, we discuss the molecular definition of upstream-type CRMs.

Curcumin is a promising anti-cancer drug but its applications in cancer therapy are limited due to its poor solubility, short half-life and low bioavailability. In this study, curcumin loaded magnetic alginate / chitosan nanoparticles were fabricated to improve the bioavailability, uptake efficiency and cytotoxicity of curcumin to MDA-MB-231 breast cancer cells. Alginate and chitosan were deposited on Fe3O4 magnetic nanoparticles based on their electrostatic properties. The sizes of the nanoparticles (120-200 nm) were within the optimum range for drug delivery. Sustained curcumin release was obtained use the nanoparticles with the ability to control the curcumin release rate by altering the number of chitosan and alginate layers. Confocal fluorescence microscopy results showed that targeted delivery of curcumin with the aid of magnetic field were achieved. The FACS assay indicated that MDA-MB-231 cells treated with curcumin loaded nanoparticles had a 3-6 folds uptake efficiency to those treated with free curcumin. MTT assay indicated that the curcumin loaded nanoparticles exhibited significantly higher cytotoxicity toward MDA-MB-231 cells than toward HDF cells. The sustained release profiles, enhanced uptake efficiency and cytotoxicity to cancer cells as well as the targeting potential make MACPs a promising candidate for cancer therapy.

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.

A nanostructured electrochemical bi-sensor system for analysis of milks has been developed using the Layer by Layer technique. The non-enzymatic sensor [CHI+IL/CuPcS]2, is a layered material containing a negative film of the anionic sulfonated copper phthalocyanine (CuPcS) acting as electrocatalytic material, and a cationic layer containing a mixture of an ionic liquid (IL) (1-butyl-3-methylimidazolium tetrafluoroborate) that enhances the conductivity and chitosan (CHI) that facilitates the enzyme immobilization. The biosensor ([CHI+IL/CuPcS]2-GAO) results from the immobilization of galactose oxidase on the top of the LbL layers. FTIR, UV-vis and AFM have confirmed the proposed structure and cyclic voltammetry has demonstrated the amplification caused by the combination of materials in the film. Sensors have been combined to form an electronic tongue for milk analysis. Principal Component Analysis has revealed the ability of the sensor system to discriminate between milk samples with different lactose content. Using PLS-1 calibration models, correlations have been found between the voltammetric signals and chemical parameters measured by classical methods. PLS-1 models provide excellent correlations with lactose content. Additional information about other components such as fats, proteins and acidity can also be obtained. The method developed is simple and the short response time permits its use in assaying milk samples on-line.

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 present study examined and compared the effects of high- and low-molecular weight (MW) chitosan, a nutraceutical, on intestinal and liver lipid metabolism in rats fed with high-fat diet. Both high- and low-MW chitosan decreased liver weight, elongated small intestine, improved the dysregulation of blood lipids and liver fat accumulation, and increased fecal lipid excretion in high-fat diet-fed rats. Supplementation of both high- and low-MW chitosan significantly inhibited the decreased phosphorylated AMP-activated protein kinase (AMPK)α and peroxisome proliferator-activated receptor (PPAR)α protein expressions and the increased lipogenesis/cholesterogenesis-associated protein expressions (sterol regulatory element binding protein (SREBP)1c, SREBP2, and PPARγ) and the decreased apolipoprotein (Apo)E and microsomal triglyceride transfer protein (MTTP) protein expressions in the livers of high-fat diet-fed rats. Both high and low-MW chitosan supplementation could also suppress the increased MTTP protein expression and the decreased angiopoietin-like protein (Angptl)4 protein expression in the intestines of high-fat diet-fed rats. Comparison between high and low-MW chitosan, high-MW chitosan has a higher efficiency than low-MW chitosan on the inhibition of intestinal lipid absorption and the increase of hepatic fatty acid oxidation, which can improve liver lipid biosynthesis and accumulation.

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. %.

Emergence of more virulent forms of human pathogenic bacteria with multi drug resistance is a serious global issue and requires alternative control strategies. The current study was focused to investigate the antibacterial and antibiofilm potential of ferulic acid grafted chitosan (CFA) against Listeria monocytogenes (LM), Pseudomonas aeruginosa (PA), and Staphylococcus aureus (SA). The present result showed that CFA at 64 µg/mL concentration exhibit bactericidal action against LM and SA (>4 log reduction) and bacteriostatic action against PA (<2 log CFU) within 24 h of incubation. Further studies based on propidium iodide uptake assay, measurement of material released from the cell, and electron microscopic analysis revealed that the bactericidal action of CFA was due to the altered membrane integrity and permeability. CFA dose-dependently inhibited biofilm formation (52-89% range), its metabolic activity (30.8-75.1% range) and eradicated mature biofilms, and reduced viability (71-82% range) of the test bacteria. Also, the swarming motility of LM was differentially affected at sub-MIC concentration of CFA. In the present study, the ability of CFA to kill and alter the virulence production in human pathogenic bacteria will insight a new scope for the application of these biomaterials in healthcare to effectively treat bacterial infections.

In this work, we synthesized chitosan grafted-poly acrylic acid (CS-g-PA) through surface-initiated atom transfer radical polymerization (SI-ATRP). We also studied the adsorption process of copper and lead ions onto CS-g-PA surface. Adsorption equilibrium studies indicated pH 4.0 as the best pH for the adsorption process, while the maximum adsorption capacity for Pb2+ ions was 98 mg*g-1 and for Cu2+ was 164 mg*g-1, higher adsorption capacities than chitosan alone (CS), where Pb2+ was only 14.8 mg*g-1and Cu2+ was 140 mg*g-1, respectively. Furthermore, the adsorption studies indicated that Langmuir model describes all the experimental data. All these results suggest that the new CS-g-PA polymers had potential as adsorbent for hazardous and toxic metal ions produced by different industries.

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.

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.

Engineering of drug nanocarriers combining fine-tuned mucoadhesive/mucopenetrating properties is currently being investigated to ensure more efficient mucosal drug delivery. Aiming to improve the transmucosal delivery of hydrophobic drugs, we designed a novel kind nanogel produced by the self-assembly of amphiphilic chitosan graft copolymers ionotropically crosslinked with sodium tripolyphosphate. In this work, we synthesized for the first time chitosan-g-poly(methyl methacrylate) nanoparticles thiolated by the conjugation of N-acetyl cysteine. First, we confirmed that both non-crosslinked and crosslinked nanoparticles in the 0.05-0.1% w/v concentration range display very good cell compatibility in two cell lines that are relevant to oral delivery, Caco2 cells that mimic the intestinal epithelium and HT29-MTX cells that produce mucin. Then, we evaluated the effect of crosslinking, nanoparticle concentration and thiolation on the permeability in vitro utilizing monolayers of (i) Caco2 and (ii) Caco2:HT29-MTX cells (9:1 cell number ratio). Results confirmed that the ability of the nanoparticles to cross Caco2 monolayer was affected by the crosslinking. In addition, thiolated nanoparticles interact more strongly with mucin, resulting in a decrease of the apparent permeability coefficient (Papp) compared to the pristine nanoparticles. Moreover, for all the nanoparticles, higher concentration resulted in lower Papp suggesting indicating that the transport pathways could undergo saturation.

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 functionalization of polymeric substances is of great interest for the development of innovative materials for advanced applications. For many decades, the functionalization of chitosan has been a convenient way to improve its properties with the aim to prepare new materials with specialized characteristics. In the present article, we summarize the latest methods for the modification and derivatization of chitin and chitosan, trying to introduce specific functional groups under experimental conditions, which allow a control over the macromolecular architecture. This is motivated because an understanding of the interdependence between chemical structure and properties is an important condition for proposing innovative materials. New advances in methods and strategies of functionalization such as click chemistry approach, grafting onto copolymerization, coupling with cyclodextrins and reactions in ionic liquids are discussed.

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.

Immobilized metal ion affinity adsorbents have been widely used in separation technique to purify proteins. Due to the leakage of metal ion from the adsorbents, there is no metal ion affinity adsorbent for hemoperfusion has been applied to clinical trial. In this study, in order to prevent the leakage of Zn²⁺ loaded from cellulose beads based adsorbent, improve its stability and adsorption capacity for testosterone, Freeze-drying method was used to enhance the porosity of cellulose beads, improve the surface area of the cellulose beads and adsorption capacity for testosterone. Chitosan was used to coat the adsorbents for preventing the leakage of Zn²⁺ loaded and improve the adsorbent’s stability. Moreover, the factors affecting adsorption ability and some components in plasma were also investigated. The results indicate the adsorption ability of the adsorbent can be significantly improved by freeze-drying. After the adsorbent was coated with 0.02% chitosan solution, the highest adsorption percentage reached 48%. During adsorption, the Zn²⁺ concentration in plasma did not rise. In addition, the adsorption percentage for total proteins was below 15%. The results may be caused by the pore size and surface area of the adsorbent enlarged via freeze-drying, and the chitosan solution went into the pores and coated the outer and inner surface of the adsorbent. The adsorbent has a potential clinical application to remove testosterone in patients with recurrent and metastatic prostate cancer.

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.

The object of this study was to discover an alternative therapeutic agent with fewer side effects against acne vulgaris, which is one of the most common skin diseases. Acne vulgaris often associates with acne-related bacteria such as <i>Propionibacterium acnes</i>, <i>Staphylococcus epidermidis</i>, <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i>, some of which exhibit a resistant against commercial antibiotics used in the treatment of acne vulgaris (tetracycline, erythromycin, and lincomycin). In the current study, we evaluated <i>in vitro</i> antibacterial activity of chitosan-phytochemical conjugates against acne-related bacteria. Three of chitosan-phytochemical conjugates used in this study showed stronger antibacterial activity than that of chitosan (unmodified control). Chitosan-caffeic acid conjugate (CCA) exhibited the highest antibacterial activity against acne-related bacteria with minimum inhibitory concentration values of 8 μg/mL to 256 μg/mL. In addition, the MICs of antibiotics against antibiotic resistant <i>P. acnes</i> and <i>P. aeruginosa</i> strains were dramatically reduced in the combination with CCA, suggesting that CCA would restore the antibacterial activity of the antibiotics. The analysis of fractional inhibitory concentration indices clearly revealed a synergistic antibacterial effect between CCA and the antibiotics. Thus, the median ∑FIC values against the antibiotic resistant bacterial strains were ranged from 0.375 to 0.533 in the combination mode of CCA and antibiotics.

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.

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.