Biopolymers最新文献

This study presents a feasible, one-pot synthesis approach for the preparation of a composite biopolymer material derived from tamarind seed xyloglucan (XG) by utilizing isocyanate chemistry. Through a facile reaction process, urethane bonds are formed in XG, resulting in the formation of a crosslinked network. FTIR spectra confirm the successful urethane link formation in XG via the OH-NCO reaction, and CHN analysis provides insights into the elemental composition. The synthesized XG-urethane composite (U-XG) exhibits enhanced thermal stability compared to native XG, with an enhanced degradation temperature (T_5%) of 276°C (XG marked T_5% at a lower temperature of 163°C). The optimized geometric structure, hydrogen bond types, and hydrogen bond strength of the synthesized U-XG are computationally studied by density functional theory (DFT) at the B3LYP/6-31G(d,p) level. This study also investigates the antibacterial efficacy of both XG and U-XG against a panel of pathogenic bacteria, including gram-positive bacteria such as S. aureus and S. epidermidis, as well as gram-negative E. coli. The U-XG demonstrates superior antibacterial activity against S. epidermidis compared to pristine XG. This research showcases the feasibility of a one-pot synthesis approach for preparing urethane-linked XG with enhanced thermal properties and superior antibacterial activity, offering promising prospects for biomedical and antimicrobial applications.

This study investigates the enhancement of biodegradable gelatin films through the incorporation of glycerol as a plasticizer, and citric acid and zinc oxide as cross-linkers. The results showed notable improvements in various properties, including solubility, swelling behavior, thickness, pH, biodegradability, and both mechanical and thermal characteristics. The films demonstrated complete water solubility and UV–visible light absorbance in the 280–480 nm range. Soil burial tests indicated gradual weight loss over 15 days, leading to complete degradation. Structural and thermal analyses via FTIR and TGA confirmed the films' integrity and stability. Additionally, the study highlighted the effectiveness of these modified films in adsorbing copper (II) ions from acidic solutions, showcasing their potential for environmental applications like heavy metal remediation. These findings emphasize the potential of tailored additive combinations to produce biodegradable films with enhanced properties and functionality.

Cellulose is one of the most abundant biopolymers in nature. Despite being the subject of research in various fields, it is not as famous as chitosan in catalyst design. Herein, a novel thiourea-functionalized cellulose (CTU-6) was synthesized as a robust hydrogen bonding catalyst with the degree of substitution (DS) of 0.84. CTU-6 was characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), x-ray powder diffraction (XRD), proton nuclear magnetic resonance spectroscopy (¹HNMR), solid-state cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS ¹³C-NMR), thermal gravimetric analysis (TGA) and elementel analysis. CTU-6 catalyzed the direct asymmetric Mannich reaction between acetone, aniline, and various aromatic aldehydes in cooperation with L-proline. The reaction exhibited excellent enantioselectivity, achieving up to 98% enantiomeric excess (ee) at room temperature. Incorporating trifluoromethylphenyl-substituted thiourea into the cellulose framework leverages its ability to form hydrogen bonds, thereby enabling precise control over the asymmetric induction. This study highlights the potential of cellulose-based catalysts in advancing asymmetric synthesis and their versatility in various organic reactions in cooperation with small chiral ligands. This synergy not only facilitates the efficient catalytic process but also improves the stereochemical outcomes of the reactions. This method underscores the importance of utilizing renewable and versatile cellulose materials in combination with chiral auxiliaries to achieve high levels of enantioselectivity.

This study focused on seaweed-based biomembrane development. The physical, mechanical, thermal, and biological properties of the fabricated films with different combinations of materials, such as agar, chitosan, poly(vinyl) alcohol (PVA), and quercetin, were characterized. The surface morphology of the films was analyzed using SEM. The maximum tensile strength (53.11 N/mm²), elongation at break (3.42%), and Young's modulus (15.52) of the biomembrane were recorded for the agar + chitosan combination. FT-Raman analysis confirmed the functional groups shift between the biopolymer and plasticizer used in this study. TG-DSC analysis of the biomembranes revealed a T_g in the range of 92.80°C–115°C. The maximum antioxidant activity was reported for quercetin (58.62%), and the maximum antimicrobial activity was observed for the chitosan and quercetin compounds against E. coli. A minimum hemolysis of 0.95% was achieved for the combination of agar + quercetin (AQ), agar + PEG (APE), Gracilaria corticata extract + PVA + quercetin (GCPQ) and agar + chitosan (AC) biomembranes. The minimum cytotoxicity of the biomembrane was 62.51% and 63.87% for Gracilaria corticata extract + PVA + quercetin (GCPQ), and agar + PVA, respectively. The proposed biomembrane films were found to be suitable for biomedical and packaging applications.

Polyhydroxyalkanoates are biodegradable, natural polyesters with the potential to replace petroleum-based plastics. However, high production costs limit their competitiveness. This study assessed the ability of Halomonas boliviensis, a halophilic bacterium, to synthesize polyhydroxybutyrate (PHB) from an agricultural residue, oil palm empty fruit bunch (OPEFB), in highly saline solutions that minimize contamination risk. OPEFB, containing glucose, xylose, and arabinose, offers a cost-effective alternative to pure sugar substrates and aids in waste management. PHB production from OPEFB was compared with fermentations using these sugars. H. boliviensis successfully synthesized PHB from all substrates, achieving the highest PHB content from glucose (54.63%), followed by xylose (40.18%), OPEFB (33.59%), and arabinose (33.52%). Glucose in the OPEFB hydrolysate was entirely depleted after 72 h, while xylose showed minimal consumption. This research highlights the potential of using low-cost carbon sources like OPEFB for PHB production. Future research should focus on optimizing the fermentation process to increase PHB yields, making it a more viable alternative to traditional plastics.

Silicon (Si) is a highly abundant mineral in Earth's crust. It plays a vital role in plant growth, providing mechanical support, enhancing grain yield, facilitating mineral nutrition, and aiding stress response mechanisms. The intricate relationship between silicification and lignin chemistry significantly impacts cell wall structure. Yet, the precise influence of Si on lignin synthesis remains elusive. This study investigated the interaction between Si and lignin model compounds during in vitro synthesis. Employing spectroscopic and microscopic analyses, we delineated how Si concentrations modulate lignin polymerization dynamics, particularly affecting molecular conformation and aggregation behavior over time. Fluctuations in the polymer structure are directly related to both the synthesis time and the concentration of silica. Our results demonstrate that lower Si concentrations promote the aggregation of lignin oligomers into larger particles, while higher concentrations increase the possibility of oligomer repulsion, thus preventing particle growth. These findings elucidate the intricate interplay between Si and lignin, which is crucial for understanding plant cell wall structure and stress resilience. Moreover, the results provide insights for developing lignin-silica materials with increasing applications in industry and medicine.

In this study, scaffolds based on natural polymer gelatin A, blended with polyvinylpyrrolidone were crosslinked by genipin (0.5 and 1 wt%), in order to investigate their mechanical performance and potential for biomedical application. Semi-solid extrusion (SSE) 3D printing technique was used, enabling in situ crosslinking of the blend during processing. Swelling test showed that the swelling ratio reduces with higher concentration of genipin due to an increased crosslinking. The FTIR analysis confirmed the crosslinking of scaffolds by genipin. DSC analysis and mechanical testing have shown improved thermal and mechanical properties. Morphological analysis of scaffolds by FESEM showed increased toughening of the material with the crosslinking. Tensile strength and microhardness showed a significant rise in scaffolds with the increase in genipin content, which was up to 93.8% and 125.3%, respectively. These findings were in accordance with morphological features present in samples. The biological effect of the scaffold matrix system was evaluated by qualitative and quantitative cytotoxicity assessment in vitro, demonstrating the absence of cytotoxicity in tested preparations in a direct test. The cytotoxicity index based on the metabolic activity of cells in an indirect test showed up to 20% reduction of viability compared with the control, confirming the absence of cytotoxicity, which was additionally verified by propidium iodine staining of the cells exposed to scaffolds. The presented gelatin-based crosslinked scaffolds obtained by 3D printing represent good candidates for biomedical application and future research that includes further in vitro and in vivo analysis.

Natural polymers have recently been investigated for various applications, such as 3D printing and healthcare, including treating infections. Among microbial infections, fungal diseases remain overlooked, with limited therapeutic options and high recurrence. Cutaneous cryptococcosis is an opportunistic fungal infection triggered by mechanical inoculation or hematogenous dissemination of the yeast that causes cryptococcal pneumonia and meningitis. Every year, Cryptococcus neoformans endanger the lives of immunosuppressed hosts, resulting in 180,000 deaths per year. Nonetheless, healthy individuals can also be affected by this fungal infection. Cryptococcosis has a restricted and expensive therapeutic regimen with no topical approach to skin manifestations. This study sought to create a 3D printable biodegradable polymeric hydrogel carrying ketoconazole, a low-cost antifungal drug with reported anticryptococcal activity. The developed hydrogel exhibited good 3D printability and rheological properties, including a pseudoplastic behavior. The FTIR spectra of cross-linked hydrogels revealed interactions between alginate and Ca⁺², referred to as the egg-box model, indicated by the decrease in peaks at 1600 and 1410 cm⁻¹. Furthermore, the hydrogel loaded with ketoconazole showed remarkable antifungal activity against C. neoformans strains indicated by inhibition zones, which cross-linking did not seem to affect its antifungal performance. The developed material remained structurally stable for up to 12 days (288 h) in swelling studies, and preliminary cytotoxicity performed with V79 cells indicates potential for in vivo studies and topical application.

The development of multifunctional cotton fabrics that are stain-resistant, antimicrobial, and easy to clean has sparked scientific interest as well as practical usefulness, owing to its medical and healthcare applications. The purpose of this study was to fabricate self-cleaning and antimicrobial cotton for final use by soaking the cotton fabric in nonfluorinated hybrid formulations based on quaternary chitosan-silane using the sol–gel process. The fluorine-free cotton fabric demonstrated high self-cleaning behavior and outstanding bacterial killing efficacy against E. coli and S. aureus bacteria, without altering the desired textile properties of cotton fabric. Remarkably, cotton textiles using the hybrid formulations HTACC-VTES (N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride-vinyltriethoxy silane) and TMCC-VTES (N, N, N-trimethyl chitosan chloride–vinyltriethoxy silane) demonstrated promising water contact angles of 147° and 142° respectively, indicating a move toward superhydrophobicity. In FTIR spectra, both treated cotton textiles had an absorption peak at 1208 cm⁻¹ (SiOC bending), indicating a stronger interaction between silane binding agents and the cotton substrate. The treated cotton fabric with desirable features retains its stability and endurance after 12 cycles of washing for antibacterial tests and 15 cycles for wettability tests. The manufactured cotton fabric has several potential applications, such as in personal hygiene items and medical applications.