Biopolymers最新文献

Biomaterials with antimicrobial and muco-adhesive properties represent an efficient system for different applications. In this paper, a new biomaterial based on chitosan-camphor beads and their crosslinked form with glutaraldehyde was optimized. Low and high molecular weight chitosan were considered. After an optimization procedure of blank beads preparation, various strategies were used to load camphor into chitosan beads where eight different beads suspensions were characterized for their size and encapsulation efficiency of camphor. Powdered camphor was added to the chitosan solution during the beads preparation or to preformed beads while it was dissolving in water or in 2% acetic acid solution. Results showed that, camphor addition to chitosan solution led to the formation of homogeneous suspensions with reproducible and higher encapsulation efficiencies of camphor compared to the other formulations, irrespective of the chitosan weight. In addition, these beads were stable for 1 month of storage at 4°C. The camphor loaded cross-linked beads with glutaraldehyde (referred to as Cam-beads-GA) were more stable than noncross-linked beads (Cam-beads), which also demonstrated satisfactory stability results. Camphor embedding in chitosan beads was proven to occur through hydrogen bonding and potentially imine bonds by FTIR analysis. The optimized formulations constitute a suitable delivery system for other bioactive agents.

This study aims to evaluate the impact of formulation parameters on tannic acid-crosslinked gelatine (GelTA) films, intended as a mucoadhesive matrix for extended buccal drug delivery. GelTA films were prepared using the solvent evaporation technique and screened based on their mucoadhesive and dissolution characteristics. The formulation variables included the source of gelatine (bovine and fish), tannic acid concentration, pH of the film-forming solutions, and the type and concentration of plasticisers. Subsequently, selected films underwent further characterisation (e.g., crosslinking density, stability) to elucidate their features as a drug delivery matrix. GelTA films exhibited a significantly improved dissolution time compared to the non-crosslinked film (BG-GLY20), while maintaining a substantial water uptake capacity conducive to a matrix system with extended action. The bovine GelTA film containing 5% w/w tannic acid and 20% w/w glycerine, prepared at pH 7 (BG-GLY20-7), exhibited a 1.6-fold increase in mucoadhesivity and an extended dissolution time of up to 6 h compared to BG-GLY20 (control), along with superior antioxidant and antimicrobial properties. However, stability studies indicate the need for an oxygen-free environment for film storage. In conclusion, GelTA films show promise as a buccal film matrix, offering extended dissolution times, substantial water uptake, and enhanced adhesive strength.

Dipeptides were constructed using hydrophobic amino acid residues following AMP prediction. After that Boc-modification was performed on the screened peptides and finally Boc-Phe-Trp-OMe and Boc-Trp-Trp-OMe were synthesized. Even though no inhibition zones were observed in agar well diffusion assays, minimum inhibitory concentration (MIC) analysis revealed anti-bacterial activity against both Gram-positive and Gram-negative bacteria, with MIC₉₀ ranging from 230 to 400 μg/mL. The crystal violet assay confirmed the dipeptides' biofilm eradication and disruption capabilities. Furthermore, membrane permeabilization assays indicated outer and inner membrane permeabilization, while SEM analysis revealed the formation of fibril and spherical nanostructures, likely contributing to this effect. The peptides also exhibited resistance to protein adsorption, non-cytotoxicity, and non-hemolytic properties, making them promising broad-spectrum anti-bacterial agents with biofilm eradication and disruption potential. This study concludes that Boc-protected phenylalanine- and tryptophan-based dipeptides can self-assemble and can be used as broad-spectrum anti-bacterial agents. The self-assembly of these peptides offers a versatile platform for designing biomaterials with tailored properties and functionalities. Research exploring the anti-bacterial potential of Boc-protected dipeptides has been limited, prompting our investigation to shed light on this overlooked area. Our analysis of synthesized Boc-protected dipeptides revealed notable anti-bacterial activity, marking a significant advancement. This finding suggests that these dipeptides could emerge as potent, broad-spectrum anti-bacterial agents, addressing the urgent need for effective treatments against bacterial resistance and opening new avenues in therapy. This study not only enhances our understanding of these dipeptides but also highlights their potential as innovative and efficacious anti-bacterial agents, making a substantial impact in the clinical field.

One of the current biotechnological applications is nanofiber applications made from algae using the electrospinning technique. Nanofibers containing poly-caprolactone (PCL) extracted from the brown seaweed Hijiki (Sargassum fusiforme) were prepared using electrospinning technique. Water extraction was performed to preserve the integrity of Hijiki components, ensuring their efficacy in subsequent electrospinning and characterization. The morphology and chemical composition of the nanofibers were characterized using field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR) analyses. Hijiki was found to combine well with electrospun biocompatible polymers and effectively provide the common properties of these materials. The cytotoxicity of algae-doped PCL nanofibers was examined in vitro using liver cancer and liver healthy cell lines (HepG2 and The-2). Among hepatic tumor cell lines, the HepG2 cell line has been preferred due to its wide range of scientific applications. Although the nanofibers caused a 28% decrease in liver cancer cell lines viability (HepG2), the decrease in healthy liver cell viability (The-2) was 12%. Algae-doped PCL nanofiber applied to bacteria showed antibacterial effect. Based on the findings, Hijiki macroalgae nanofibers show great promise for tissue regeneration and band-aid applications in the medical industry.

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.