Abstract: Thermoplastic starch (TPS) can be a sustainable alternative to petrochemical plastics for flexible packaging, especially in rainforests and tropical regions where native starch sources such as cassava are abundant. However, one problem preventing TPS packaging from widespread use is its susceptibility to moisture. This study evaluated TPS formulations based on Amazonian cassava starch reinforced with plantain leaf fibers, beeswax, and low-density polyethylene (LDPE) particles. The plastic compounds were extruded to obtain pellets and then films at 120-130 °C. The resulting films were then cut and heat-sealed to obtain flexible packaging. Different properties of the TPS packages were evaluated, such as mechanical strength, water vapor transmission (WVTR), color, infrared spectrum (FT-IR), and moisture adsorption. The results showed that the formulation with beeswax (2 % w/w), plantain leaves powder (1 % w/w), and LDPE powder (2 % w/w) had a higher tensile strength (5.99 MPa) and moisture barrier (WVTR = 366.6 g m-2 d-1) compared to the control formulation only with plasticizers (glycerol and water) but without reinforcements (0.48 MPa and 1486.6 g m-2 d-1, respectively). Films with only beeswax (4 % w/w) and plantain leaves powder (2.5 % w/w) had tensile strength = 5.53 MPa and WVTR = 716.8 g m-2 d-1, with higher moisture adsorption compared to the samples with LDPE. In both cases, homogeneous and heat-sealable bags were obtained. The reinforced TPS films can be used to reduce the environmental impact generated by single-use packaging applications such as food commercialization.

Abstract: The use of metal-based species bearing existing pharmaceuticals as ligands, often resulting in enhanced bioactivity, represents an attractive strategy for the development of novel therapeutic formulations. In the context, five well-known non-steroidal anti-inflammatory drugs (NSAIDs) were employed to substitute both PPh₃ and hydride ligands in [Ru(H)₂(CO)(PPh₃)₃] (1), selectively affording, via molecular hydrogen release, neutral κ²-(O,O)-chelate complexes in satisfactory yields. Among the obtained species, two complexes coordinating diclofenac (4) and aspirin (5) were further investigated by single-crystal X-ray diffraction (SCXRD). Preliminary biological studies on the ruthenium-salicylic acid species 2 showed promising antiproliferative activity against HeLa cancer cells, consistent with the fact that NSAID–ruthenium(II) complexes represent a well-established research area for the development of novel anticancer metallotherapeutics.

Abstract: For a long time, the "biogenic theory" of petroleum origin has dominated mainstream thinking, positing that petroleum forms from the burial and thermal evolution of ancient microbial, plant, and animal remains in sedimentary environments. However, traditional theories cannot fully explain how complex biological macromolecules precisely crack into relatively simple hydrocarbon small molecules over geological time scales, and controversies remain regarding the energy sources and kinetic mechanisms of the cracking process. Integrating the core physical principle that cosmic expansion induces atomic expansion[1][3], we can construct a novel petroleum generation mechanism: petroleum is a product of sedimentary organic matter derived from microbial, plant, and animal remains, which undergoes gradual cracking and recombination of molecular structures under the sustained action of atomic expansion driven by cosmic expansion over hundreds of millions of years, ultimately transforming from complex macromolecules into hydrocarbon small molecules.

Abstract: Numerous studies show that the use of dental guides that rest on the patient's teeth improves the precision of implant placement, but the currently developed procedures and selected materials are still not perfect and could result in deviations from the planned implant position. The impact of the surgeon's hand force on the deformation of dental guides during implant placement has not yet been investigated or documented. In this study the behavior of the 3D guide model is evaluated by FEA analysis to validate the influence of the force of the surgical hand on dental guides due to their application. FEM simulation of deformation and stress was designed for four different types of dental guides that are supported on teeth for different ways of supporting the guide due to the action of the surgeon's manual force (chosen arbitrarily 30 N). The finite element simulation method performed on 5 sets of commonly used biocompatible polymer materials, Stratasys MED610 and VeroGlaze MED620, EOS PA2200, Formlabs FLSGAM01 and Stratasys ULTEM 1010, successfully numerically quantified the deformation of the dental guide caused by the surgeon's arbitrarily manual forces during manipulation. Based on the conducted analyses, guidelines were proposed for improving the design of guides, with an emphasis on optimal selection of supports, stability on the patient's anatomy, and reduction of deformations, thereby increasing the accuracy of implant placement. It was found for all four designs of dental guides that the deflection depends on the size of the arm, i.e. the distance of the support from the point of application of the force. As a result of the study, diagrams were created that serve as guidelines for the design of beam (A and A1) and cantilever (B and B1) versions of dental guides that rely on teeth. Guidelines for enhancing guide design were put out based on the analyses that were carried out, with a focus on the best choice of supports, stability on the patient's anatomy, and minimization of deformations in order to improve implant placement accuracy.

Abstract:

Archaea lipids are a source of new biomaterials for pharmaceutical and nanomedical applications; however, their classic extraction method relies on chloroform and methanol, toxic solvents that conflict with green chemistry principles. In this paper we explore the performance of an eco-friendly method for the extraction of total lipids from the haloarchaea Halorubrum tebenquichense. Using the bio-solvents ethyl acetate and ethanol in a two-step procedure, a fraction of total lipids (135 ± 41 mg phospholipids and 1.1 ± 0.4 mg bacterioruberin (BR) / 100 g cell paste) was obtained containing the same composition as that resulting from extraction with the classical solvents as confirmed by Electrospray Ionization Mass Spectrometry, although with lower phospholipid content, thus with a higher proportion of bacterioruberin. The extracted lipids were subsequently utilized for preparation of archaeosomes, which were characterized by uniform size distribution (406 ± 137 nm, 0.63 ± 0.13 polydispersity index), colloidal stability, and negative ζ potential (-38.2 ± 5.4 mV). The photoprotective potential of these archaeosomes was for the first time determined in human keratinocyte (HaCaT) cells exposed to UVB irradiation (270 mJ/cm²). Treatment with archaeosomes significantly (p< 0.05) enhanced cell viability (from ~43 to ~80 %), reduced intracellular ROS generation and proinflammatory cytokine release (TNF-α) and mitigated UVB-induced apoptosis compared to untreated controls, indicating effective cytoprotection. This study demonstrates that ethyl acetate–ethanol-based extraction offers an alternative for archaeal lipid recovery and highlights the potential of archaeosomes as natural photoprotective agents for skincare applications.

Abstract:

This study reports the fabrication of chitosan/carboxymethyl cellulose (C/M) nanocomposites by electrolyte gelation-spray drying and the evaluation of their antibacterial performance as carriers for the antibiotic ampicillin. Chitosan (C), a cationic biopolymer derived from chitin, was combined with the anionic polysaccharide carboxymethyl cellulose (M) at different mass ratios to form stable nanocomposites via electrostatic interactions and then collected by a spraying dryer. The resulting particles exhibited mean diameters ranging from 800 to 1500 nm and zeta potentials varying from +90 to −40 mV, depending on the C:M ratio. The optimal formulation (C:M = 2:1 ratio) achieved a high recovery yield (71.1%) and ampicillin encapsulation efficiency EE (82.4%). Fourier transform infrared spectroscopy (FTIR) confirmed the presence of hydrogen bonding and ionic interactions among C:M, and ampicillin within the nanocomposite matrix. The nano-microcomposites demonstrated controlled ampicillin release and pronounced antibacterial activity against Staphylococcus aureus, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.2 µg/mL and 5.3 µg/mL, respectively, which were lower than those of free ampicillin. These results indicate that the chitosan/carboxymethyl cellulose nano-microcomposites are promising, eco-friendly carriers for antibiotic delivery and antibacterial applications.

Abstract: Multidrug resistance (MDR), frequently mediated by over-expression of the P-glycoprotein (P-gp/ABCB1) efflux transporter, remains a major challenge in the treatment of leukemia by limiting intracellular accumulation of chemotherapeutic agents such as daunorubicin (DNR). This study evaluates the applicability of a microfluidic-based single-cell biochip to investigate the reversal effects of microgram-level ginsenosides on daunorubicin uptake in multidrug-resistant leukemia cells. Pure ginsenosides are difficult to obtain in bulk and are typically available only in milligram quantities, which restricts their evaluation using conventional MDR assays such as flow cytometry that require large cell populations and substantial amounts of compound. To address this limitation, a microfluidic single-cell biochip (SCB) requiring microgram quantities of ginsenosides (< 100 µg) and fewer than ten cells was employed. Intracellular DNR accumulation was measured in the CEM/VLB1000 leukemia cell line following treatment with DNR alone or in combination with ginsenoside Rg3-R, ginsenoside Rg3-S, 20(S)-protopanaxatriol (PPT), and 20(S)-protopanaxadiol (PPD), in order to compare their relative efficacy in enhancing drug accumulation. Although Rg3-R and Rg3-S share highly similar chemical structures and are glycosylated derivatives of the PPD aglycone, Rg3-S exhibited greater potency in increasing intracellular daunorubicin accumulation than Rg3-R, and both were more effective than PPD. These findings underscore the importance of ginsenoside stereochemistry modulating P-gp associated drug resistance and demonstrate the utility of the SCB platform for quantifying daunorubicin accumulation in multidrug resistant leukemia cells at single cell resolution.

Abstract:

Colon-targeted drug delivery systems are of considerable interest for improving the therapeutic efficacy of anticancer agents while minimizing systemic side effects. In this study, semi-interpenetrating polymer network (semi-IPN) hydrogels based on methacrylated dextran and native inulin were designed as biodegradable carriers for the colon-specific delivery of uracil as a model antitumor compound. The hydrogels were synthesized via free-radical polymerization, using diethylene glycol diacrylate (DEGDA) as a crosslinking agent at varying concentrations (5, 7.5, and 10 wt%), and their structural, thermal, and biological properties were systematically evaluated. Fourier transform infrared spectroscopy (FTIR) confirmed successful crosslinking and physical incorporation of uracil through hydrogen bonding. At the same time, differential scanning calorimetry (DSC) revealed an increase in glass transition temperature (T_g) with increasing crosslinking density (149, 153, and 156 °C, respectively). Swelling studies demonstrated relaxation-controlled, first-order swelling kinetics under physiological conditions (pH 7.4, 37 °C), and high gel fraction values (84.75, 91.34, 94.90%, respectively) indicated stable network formation. All formulations exhibited high encapsulation efficiencies (>86%), which increased with increasing crosslinker content, consistent with the observed gel fraction values. Simulated in vitro gastrointestinal digestion showed negligible drug release under gastric conditions and controlled release in the intestinal phase, primarily governed by crosslinking density. Antimicrobial assessment against Escherichia coli and Staphylococcus epidermidis, used as an initial or indirect indicator of cytotoxic potential, revealed no inhibitory activity, suggesting low biological reactivity at the screening level. Overall, the results indicate that DEGDA-crosslinked dextran/inulin semi-interpenetrating polymer network (semi-IPN) hydrogels represent promising carriers for colon-targeted antitumor drug delivery.

Abstract:

Mycelium-based composites (MBCs)—biomaterials made from fungal-inoculated substrates—are promising candidates to replace conventional materials for thermal insulation. However, many MBCs are made from hemp, a plant material that is quite difficult to source in many countries for regulation reasons, and mobilizes agricultural field at the expense of food and feed crops. Meanwhile, many of our natural and urban ecosystems are subject to invasion by plants that are just burnt or even left on place, while they may be very good substrate for MBCs. This study investigated the comparative physical and thermal properties MBCs derived from two distinct lignocellulosic feedstocks: hemp shives (a traditional material) and biomass from the highly invasive species Reynoutria japonica. Polyisocyanurate (PIR) was included as a synthetic benchmark. The MBCs produced from R. japonica demonstrated as low thermal conductivity as hemp MBCs, but also as the PIR standard. However, they exhibited suboptimal physical characteristics: higher bulk density (166 vs 128 kg/m3 for hemp) and significantly greater water absorption (7.5% vs 3.5%volume uptake after 2 minutes). This suggest that they are a less viable alternative to hemp-based MBCs for heat insulation applications.

Abstract: The increasing demand for seafood recorded over the years led to an increase in the by-products produced by the seafood processing sector. These by-products, which can represent up to 70% of the processed product, are rich in nutrients and bioactive compounds, so if recovered, by means of eco-friendly methods, they can be used in lot of sectors, such as food, packaging, cosmetics and pharmaceutics. In the present work, two lactic acid bacteria (Lactobacillus lactis and L. brevis) and the yeast Yarrowia lipolytica, able to produce organic acids and proteases during the fermentation process, were used to extract chitin from deep-water shrimp (Aristeus antennatus) by-products. The results showed that L. lactis was the most effective microorganism in removing both the mineral and protein fractions, being chosen for the optimization of the extraction technique of chitin, eventually converted in chitosan. The chitosan showed a deacetylation degree (DD) of 82%, which led to good film-forming capacity. The developed biological technique allowed valorizing shrimp by-products by recovering chitin and chitosan, which was able to produce biofilm to be employed to prolong seafood shelf life, in a circular economy point of view, contributing even more to increase the sustainability of the production sector.

Abstract: Carbon dots (CDs) have emerged as a distinct class of fluorescent nanomaterials distinguished by their tunable physicochemical properties, ultrasmall size, exceptional photoluminescence, versatile surface chemistry, high biocompatibility, and chemical stability, positioning them as promising candidates for biomedical applications ranging from sensing and imaging to drug delivery and theranostics. As CDs increasingly transition toward biological and clinical use, a fundamental understanding of their interactions with biological membranes becomes essential, as cellular membranes govern nanoparticle uptake, intracellular transport, and therapeutic performance. Model membrane systems, such as phospholipid vesicles and liposomes, offer controllable platforms to elucidate CD-membrane interactions by isolating key physicochemical variables otherwise obscured in complex biological environments. Recent studies demonstrate that CD surface chemistry, charge, heteroatom doping, size, and hydrophobicity, together with membrane composition, packing density, and phase behavior, dictate nanoparticle adsorption, insertion, diffusion, and membrane perturbation. In addition, CD-liposome hybrid systems have gained momentum as multifunctional nanoplatforms that couple the fluorescence and traceability of CDs with the encapsulation capacity and biocompatibility of lipid vesicles, enabling imaging-guided drug delivery and responsive theranostic systems. This review consolidates current insights into the mechanistic principles governing CD interactions with model membranes and highlights advances in CD-liposome hybrid nanostructures. By bridging fundamental nanoscale interactions with translational nanomedicine strategies, this work provides a framework for the rational design of next-generation CD-based biointerfaces with optimized structural, optical, and biological performance.

Abstract: Protein-based materials such as human serum albumin (HSA) have demonstrated significant potential for the development of novel wound management materials. For the first time, the formation of HSA-based hydrogels was proposed using a combination of ther-mal- and ethanol-induced approaches. The combination of phosphate-buffered saline and limited (up to 20% v/v) ethanol content offers a promising strategy for fabricating human serum albumin-based hydrogels with tunable properties. The hydrogel formation was studied using in situ DLS for qualitative and semi-quantitative analysis of the patterns of protein hydrogel formation through thermally induced gelation. The rheological proper-ties of human serum albumin-based hydrogels were investigated. Hydrogels synthesized via thermally induced gelation using a denaturing agent exhibit a dynamic viscosity ranging from 100 to 10,000 mPa·s. These human serum albumin-based hydrogels repre-sent a promising platform for developing topical therapeutic agents for wound manage-ment and tissue engineering applications. This study investigated the kinetics of tetracy-cline release from human serum albumin-based hydrogels in phosphate-buffered saline (PBS) and fetal bovine serum (FBS). All tested formulations of human serum albumin (HSA)-based hydrogels loaded with tetracycline (0.15 mg/mL) was demonstrated antibacterial activity of against Staphylococcus aureus strains.

Abstract: The design of biomaterial scaffolds for bone tissue engineering requires a balance between bioactivity, porosity, mechanical stability, and osteoinductivity. Kappa- (KC) and iota-carrageenan (IC) have been explored for scaffold fabrication due to their biocompatibility and structural similarity to glycosaminoglycans. However, there are limited reports on how their distinct sulfation degree affects the osteogenic differentiation of cells cultured on them. While laponite has been reported as an osteoinductive nanoclay, its combined effect with different carrageenan types and its concentration-dependent effect on scaffold functionality remain unexplored. Therefore, we developed composite scaffolds comprising poly(vinyl alcohol) (PVA) and gelatin (GEL), reinforced with kappa- or iota-carrageenan (KC, IC) and functionalized with two different concentrations of laponite (LAP), 0.5 and 1% w/v, to monitor composition-structure-function relationships. The scaffolds were fabricated via lyophilization and dual crosslinking, and characterized for their physicochemical, structural, mechanical, and biological properties. The incorporation of both carrageenans into scaffolds, maintained high swelling ratios of 600% after 24 h, and increased porosity without altering their apparent density (0.09-0.11 g/cm3), whereas LAP preserved interconnectivity, densified pore walls, raised their compressive modulus at >220 kPa, and improved stability (&gt;60% mass retained after 40 days). In vitro validation using MC3T3-E1 pre-osteoblastic cells demonstrated robust cytocompatibility, with the LAP-containing scaffolds significantly promoting cell adhesion, proliferation, and osteogenic differentiation, evidenced by elevated alkaline phosphatase activity, calcium production and collagen secretion. Direct comparison between KC and IC scaffolds confirmed that differences in sulfate substitution modulated scaffold stiffness, swelling, and degradation, while variation in LAP concentration affected the biological response, with the 0.5 wt% concentration favoring early cell proliferation, whereas the 1 wt% significantly promoted the osteogenic differentiation. This compositional strategy demonstrates how tuning the interplay between carrageenan and laponite can balance scaffold hydration, mechanical and biological properties, thereby guiding the design of scaffolds for bone repair.

Abstract: (1) Background: The development of a functional polyelectrolyte layer scaffold coating that promotes neural cell adhesion and growth is essential for improving the perfor-mance of neuro-regenerative materials interfaces. In this study, polyelectrolyte-based layer coatings modified with copper nanoparticles (CuNPs) and iron(II, III) oxide na-noparticles (Fe3O4NPs) were produced to enhance their physicochemical properties. (2) Methods: The effect of different concentrations of CuNPs and Fe3O4NPs incorporated within the coatings was verified in vitro on the neural stem cell line of mice, NE-4C, to assess the interaction in the material-cells interface. SEM was used to assess the mor-phology of cells immobilized within the nanocomposite material. Fluorescent evalua-tion and mitochondrial activity assays were performed to assess cell function immobi-lized on the material. (3) Results: Among others, the results of the mitochondrial activ-ity evaluation of NE-4C cells indicated that a higher share of Fe3O4NPs allows an in-crease in mitochondrial activity in neural cells in both PLL- and PEI-based materials. However, the involvement of a higher share (100 ppm) of CuNPs in a PLL-based ma-terial induced a decline in cell activity of up to 20% compared with a material not in-corporating nanoparticles. In the case of coating with CuNPs or Fe3O4NPs, the dependence of cell function on the proportion of Fe3O4NPs was observed. However, fluorescence observations confirmed the presence of both astrocytes and neurons on all selected scaffolds. The culture of the material containing Fe3O4NPs showed a greater proportion of neurons in the cell pop-ulation than the material containing CuNPs. (4) Conclusions: It was shown that the use of selected metallic nanoparticles affects both the morphology and function of neural cells. The obtained results suggest that nanoparticle incorporation can modu-late the interfacial environment that interacts with neural cells.

Abstract:

The main limitation of high-temperature drawing approach for tailoring crystallization and molecular orientation of poly-l-lactide (PLLA) toward ultrasound- active piezoelectric structures is set by intrinsic properties of the processed polymer, including low melting / softening elasticity and slow crystallization kinetics. Here we found that application of different contacting layers, including polytetrafluoroethylene (PTFE) (as Teflon and Teflon S), cellulose (paper) or polyimine (Kapton) deposited at the surface of PLLA, significantly affects the drawing process and tailors its oriented crystallization and molecular chain orientation. Consequently the contacting layers contribute to piezoelectric properties of PLLA, affect their activation by ultrasound and generated electro-signal. Human keratinocytes (HaCaT cells) grown stimulated on these surfaces are shown to receive and respond to the transferred stimuli by activation of the cytoskeleton and directional migration. The high-temperature drawing approach with contacting layers is simple, solvent-free and economically continent way for broadening limitations of classical high-temperature drawing which opens new possibilities for further tailoring piezoelectricity of organic piezoelectrics.

Abstract: African catfish (Clarias gariepinus, AC) is one of the most widely farmed freshwater fish species in Central Europe. Processing operations generate up to 55% by-products (BPs), predominantly carcasses rich in proteins, lipids, and minerals. This study develops a comprehensive valorization process for ACBPs to recover gelatin, protein hydrolysate, fish oil, and pigments. The processing protocol comprised sequential washing, oil extraction, demineralization, and biotechnological treatment to cleave the collagen quaternary structure. A two-factor experimental design was employed to optimize the processing conditions. The factors included the extraction temperatures of the first (35–45 °C) and second fraction (50–60 °C). The integrated process yielded 18.2 ± 1.2% fish oil, 9.8 ± 2.1 % protein hydrolysate, 1.7 ± 0.7 % pigment extract, and 25.3–37.8 % gelatin. Optimal conditions (35 °C/60 °C) produced gelatin with gel strength of 168.8 ± 3.6 Bloom, dynamic viscosity of 2.48 ± 0.02 mPa·s, yield of 34.76 ± 1.95 %. Life cycle assessment (LCA) identified two primary environmental hotspots: water consumption and energy demand. This near-zero-waste biorefinery demonstrates the potential for comprehensive valorization of aquaculture BPs into multiple value-added bioproducts.

Abstract: The development of non-noble metal catalysts provides a cost-effective and sustainable route for glucose oxidation to gluconic acid. In this study, a series of catalysts based on inexpensive transition metals (Cr, Cu, Ni, Fe) and/or Au were synthesized using siliceous supports (SiO₂ and MCM-41) and systematically evaluated. The aim was to partially or fully replace noble metals with lower-cost alternatives, while maintaining high catalytic performance. Comprehensive characterization—including ICP-AES for composition, N₂ adsorption–desorption for porosity, XRD for structure, H₂-TPR for reducibility, and NH₃-TPD for acidity—was conducted to establish structure–property relationships. Among the tested catalysts, Ni- and Fe-based systems exhibited superior stability, with NiO/SiO₂ achieving gluconic acid yields comparable to Au. The bimetallic Au–Ni/SiO₂ catalyst displayed enhanced metal–support interactions and minimal leaching (< 2 %), while Au–Fe/SiO₂ improved selectivity, yielding up to 23 % gluconic acid, surpassing 5Fe/SiO₂ (18 %) and 0.3Au/SiO₂ (15 %), albeit with lower stability. These results highlight the potential of low-cost transition-metal and bimetallic catalysts as efficient and eco-nomically viable systems for selective glucose oxidation, providing insights for rational catalyst design in sustainable carbohydrate valorization.

Abstract: This paper reconstructs mykoholz, a mid-20th-century East German, white-rot–mediated bio-modification of solid hardwood, as a missing link in fungal materials engineering. From patents, factory records, declassified reports, and recent literature, we recover process parameters (end-grain inoculation; 3-4 mo incubation in controlled vaults; staged drying/impregnation) and performance outcomes (75-90% density reduction, high porosity, stress relief) enabling uses from pencils to glass-molding and acoustic parts. We benchmark mykoholz against modern mycelium-based composites (MBCs) across substrate, process control, mechanics, energy, scalability, and environmental profile, showing complementarity: mykoholz reconfigures solid wood in situ, whereas MBCs grow moldable composites from lignocellulosic waste. We trace the 1965 industrial decline to quality variance and insufficient climate control, and show how AI-assisted bioprocessing, climate-controlled incubation, and selective delignification could resolve these limits. We propose hybrid fungal systems, and a research agenda covering standardized replication, LCA, acoustic/thermal benchmarks, and pilot-scale automation, positioning mykoholz as low-energy circular bioengineering with actionable principles for scalable, eco-compatible materials.

Abstract: Electrospinning is a versatile technique for fabricating nanofibrous scaffolds that mimic the extracellular matrix (ECM), offering a biomimetic environment for tissue engineering applications. This study investigates the influence of key processing parameters, polyvinylpyrrolidone (PVP) concentration, flow rate, applied voltage, and needle diameter, on fiber formation and morphology. Electrospinning using ethanol as solvent was unsuccessful at lower PVP concentrations (40–50% w/v) due to inadequate viscosity and chain entanglement. Increasing the concentration to 60% (w/v), with a flow rate of 1 mL/h and voltage of 26 kV, enabled stable fiber formation using 15G and 18G needles. Scanning electron microscopy (SEM) and ImageJ analysis revealed significant differences in fiber diameter: 1853.90 ± 229 nm for 15G and 647.52 ± 638 nm for 18G, demonstrating the sensitivity of electrospinning to minor parameter variations. These findings underscore the importance of systematic optimization to achieve scaffolds with uniform morphology, high porosity, and interconnected architecture, which are essential for cell attachment, nutrient diffusion, and tissue integration in regenerative medicine.

Abstract: Rapid, sensitive monitoring of fluoroquinolone residues is essential for medicine and the food industry. We report a “turn-on” fluorescent biosensor based on nitrogen-doped carbon quantum dots (N-CQDs) prepared by a one-pot hydrothermal route using cotton waste as the carbon source and o-phenylenediamine as the nitrogen passivator. The N-CQDs display a quantum yield of 42% and stable photoluminescence. Levofloxacin binds to surface functional groups on the N-CQDs and inhibits photoinduced electron transfer (PET), restoring radiative decay and enhancing fluorescence. The sensor affords an ultralow LOD of 0.55 nM and a linear range of 1.83–40.00 nM with high selectivity against common interferents. The method was successfully applied to pharmaceutical tablet extracts, raw milk, chicken meat, and urine, achieving excellent spike-recovery and precision. This work demonstrates a sustainable, low-cost nanosensor that converts agricultural waste into a high-performance optical biosensing platform for drug-residue screening across clinically and industrially relevant matrices. The approach is readily scalable and compatible with routine fluorescence instrumentation, supporting rapid decision-making in food safety and healthcare settings.