Biopolymers最新文献

Antimicrobial peptides (AMPs), produced in various organisms, including plants, as a first line of defense, are potent, functionally versatile, fast-acting small peptides with a net charge and diverse structures. Most AMPs demonstrate potent antibacterial activity, and AMPs with multimodal actions can potentially delay the development of antimicrobial resistance (AMR), one of the top 10 global public health challenges categorized by the WHO. Notably, the FDA has already approved several AMPs (Mol. Wt. ≤ 2 kDa) as antibiotics; however, there are not enough new-age antibiotics in the current pipeline to combat the looming problem of AMR in the clinic. Nevertheless, despite their potential, natural AMPs have their fair share of shortcomings for straightforward therapeutic applications. Therefore, extensive research on developing designer synthetic AMPs with broad-spectrum antimicrobial activity is currently being undertaken to mitigate the AMR challenge. In this context, we recently demonstrated a short synthetic designer AMP (SR17: ≤ 16 aa, mol. Wt. ≤ 2 kDa) that exhibits broad-spectrum bacteriostatic and bactericidal action against both gram-negative (Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii) and gram-positive (Staphylococcus aureus) bacteria. Interestingly, in gram-negative bacteria, the outer membrane proteins (OMPs) play a key role in transporting nutrients like iron from their surroundings through siderophores, which play a crucial role in various biochemical processes essential for their survival and growth. In the current study, the ability of SR17 to target the iron-transporting OMPs acting as the siderophore uptake system is investigated through computational techniques. A series of docking and molecular dynamics (MD) simulation studies involving iron transporters of various gram-negative bacteria indicate that SR17 can occupy the binding pocket in the OMPs necessary for binding of the iron-chelated siderophores, which is likely to prevent the further uptake of siderophores, affecting the growth and survival of the bacteria. Additionally, SR17 may potentially reach the bacterial cytoplasm by utilizing the siderophore uptake system and disrupt essential cytoplasmic processes, leading to the death of the bacteria, as observed in experimental studies.

This study aimed to evaluate the synergistic action of electron beam irradiated chitosan and Ampelomyces quisqualis for the management of powdery mildew, the most significant disease incited by the obligate fungus Erysiphe necator Schw. (Formerly known as Uncinula necator (Schw.) Burr.) that causes substantial losses in grapes. In vivo field trials conducted during 2020-21 and 2021-22, the evaluation of irradiated chitosan and bioagent and fungicide for the efficient in managing the grape powdery mildew disease. The fungicide sulfur 80% WDG was determined to be the most efficient. However, it was followed by a friendly combination of irradiated chitosan (150 ppm) with A. quisqualis (0.5%). Eco-friendly molecules, that is irradiated chitosan 150 ppm with A. quisqualis (0.5%), were found to be the best alternative for chemical molecules to achieve the disease control 63.60% and were identified alternative to chemical treatments to manage the powdery mildew disease of grapes. Irradiated chitosan and biocontrol agents showed synergistic action for the management of powdery mildew in grapevines.

Silk fibroin (SF), a biodegradable and biocompatible material with excellent mechanical properties, is widely utilized in food packaging and medical applications. However, regenerated SF is inherently brittle, necessitating the addition of polyethylene glycol (PEG), a nontoxic and biocompatible plasticizer, to enhance its flexibility. In this study, SF-PEG films were fabricated using two solvent systems: a single solvent (1-butyl-3-methylimidazolium chloride, BMIM Cl) and a binary solvent system (BMIM Cl and dimethyl sulfoxide, DMSO). SL-PEG films were prepared using the single solvent, while SM-PEG films were produced with the binary solvent system. The structural, mechanical, and morphological properties of the films were compared. Results showed that the SM-PEG films exhibited excellent mechanical performance, with a tensile strength of 6.9 ± 0.7 MPa, a Young's modulus of 367.0 ± 42.9 MPa, and an elongation at break of 42.6% ± 4.0%, significantly outperforming the SL-PEG films. The enhanced performance of SM-PEG films was attributed to the improved dispersion of PEG within the SF matrix, facilitated by the binary solvent system. In conclusion, the binary solvent system effectively improved the flexibility and ductility of SF-PEG films, making them better suited for applications requiring robust and adaptable biomaterials, such as in food packaging and medical applications.

This study investigated the effects of different solvent systems on the microstructure, roughness, and secondary structure of soluble eggshell membrane proteins (SEPs). The solvent system of CaCl₂/C₂H₅OH/H₂O produced tiny holes on the surface of SEP, and LiBr resulted in the formation of long holes. The saline solution increased the diameter of the protein fiber, the particle size of the solution, and the surface roughness of regenerated SEP films, mainly due to the enhanced intermolecular aggregation and precipitation. Zeta potential measurements indicated salts decreased the negative values and reduced the stability of the SEP solution. The different solutions showed similar circular dichroism waveforms. The peak intensity decreased at the positive and negative peaks, indicating that the triple helix structure of collagen was denatured to different degrees. Besides, the addition of salts decreased the content of α-helices and the β-turns and increased the content of β-sheets and random coils, indicating an increase in the disordered structure of the protein. This study contributes to a deeper understanding of the structural and functional relationships of eggshell membrane proteins, providing a vital basis for developing novel, eco-friendly, and multifunctional protein materials.

The study aims to evaluate the effects of different contents of quercetin (1%–3%) on structural and morphological characteristics of soy protein isolate (SPI) based films fabricated by the solution casting method. Prior to the preparation of the modified SPI film, quercetin incorporated SPI suspension was characterised for molecular weight distribution, particle size, and zeta potential. Addition of quercetin affected the charge distribution on the surface of protein and made it a more stable entity, as evident from more negative ζ- potential values. The as-prepared film was structurally and thermally characterised by x-ray diffraction, Raman spectroscopy, and thermogravimetric analysis. The results revealed the changes in the secondary conformation of the protein structure with a simultaneous decrease in the crystallinity of the conjugated films and an increase in the thermal stability of quercetin incorporated SPI films. Quercetin incorporated SPI film was also subjected to morphological, antioxidant, and biodegradation studies. The antioxidant activity of the modified films in terms of scavenging free radicals like 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) increased significantly due to the native antioxidative ability of quercetin. The initial phase of biodegradation was rapid, followed by a slower rate of degradation phase. FTIR studies were used to structurally characterise biodegraded samples, and the results revealed the formation of carboxyl dimer during fragmentation and disruption of peptide bonds.

Inflammation processes can cause mild to severe damage in the human body and can lead to a large number of inflammation-related diseases (IRD) such as cancer, neural, vascular, and pulmonary diseases. Limitations of anti-inflammatory drugs (AID) application are reflected in high therapeutic doses, toxicity, low bioavailability and solubility, side effects, etc. Polymeric nanosystems (PS) have been recognized as a safe and effective technology that is able to overcome these limitations by AID encapsulation and is able to answer to the specific demands of the IRD treatment. PS are attracting great attention due to their versatility, biocompatibility, low toxicity, fine-tuned properties, functionality, and ability for precise delivery of anti-inflammatory drugs to the targeted sites in the human body. This article offers an overview of three classes of polymeric nanosystems: a) dendrimers, b) polymeric micelles and polymeric nanoparticles, and c) polymeric filomicelles, as well as their properties, preparation, and application in IRD treatment. In the future, the number of PS formulations in clinical practice will certainly increase.

Cassia tora, an annual shrub, is a promising but underexplored source of galactomannan, comparable to widely used sources, such as fenugreek, guar, and locust bean. Galactomannans are heteropolysaccharides composed of galactose and mannose, valued for their role as dietary fibers and texture modifiers in food applications. This study aimed to optimize Cassia tora gum's extraction process, characterize its physiochemical properties, and quantify its galactomannan content to assess its potential as a gelling agent. The extraction process was optimized by varying key parameters, including the water-to-seed powder ratio, boiling time, and mucilage-to-ethanol ratio, achieving a 96% recovery of gum, higher than the reported yield with high purity. Physiochemical analysis revealed that the extracted gum contained 84.12% carbohydrate with a galactose-to-mannose ratio of 1:5. Galactomannan content was determined to be 55% in raw Cassia seeds. Rheological studies demonstrated a minimum gelation concentration of 75%, highlighting the gum's potential as an efficient gelling agent. These findings underscore the feasibility of utilizing Cassia tora as a sustainable and cost-effective source of galactomannan for food and industrial applications, offering a valuable alternative to conventional sources.

Guided bone regeneration (GBR) is a regenerative surgical procedure in dentistry and orthopedics. The aim of this study is to fabricate a novel nano-textured, hydrophilic thermoplastic polyurethane (TPU)-based barrier membrane containing unsaturated fatty acid, oleic acid (OLE) to assist GBR. First, TPU copolymer containing OLE in different ratios was synthesized, and GBR membranes were fabricated by the solvent casting method, and then, the surface properties were improved by alkali treatment. Thus, a TPU-OLE structure was obtained with improved surface wettability, the ability to prevent bacterial adhesion, and the capability to promote cell adhesion. The contact angle reduced from 73.3° ± 1° to 30.7° ± 0.3° at TPU-OLE3, while at TPU it decreased from 121.2° ± 2.5° to 63.6° ± 0.8° after treatment with 3 M sodium hydroxide (NaOH) solution. Furthermore, plate counting assays showed that TPU-OLE membranes displayed excellent bacterial inhibition (against Escherichia coli and Staphylococcus aureus); the control group showed 6 × 10⁷ CFU/mL of E. coli bacterial colonies, while on the plates interacting with TPU-OLE1, TPU-OLE2, and TPU-OLE3 membranes, colonies of 12 × 10⁵, 12 × 10⁵, and 24 × 10⁵ CFU/mL were observed, respectively. The bacterial count on TPU-OLE1, TPU-OLE2, and TPU-OLE3 membranes decreased by 109, 164, and 12 × 10⁵ CFU/mL at 24 h, while the control group and TPU membranes showed 1300 × 10⁵ and 600 × 10⁵ CFU/mL, respectively. The obtained results indicated that either alkali treatment or OLE-modified TPU produced a more hydrophilic and promotive surface for cell attachment. Therefore, we anticipate that alkali-treated TPU-OLE membranes have a great potential in GBR in future applications.

This study considers the development of composite from biodegradable bioplastic obtained from waste starch reinforced with chitosan obtained from snail shells. About 30 g of the starch, 8 mL of glycerol, 2 mL of olive oil, and 8 mL of vinegar were added without chitosan and made up to 150 mL with distilled water. For other samples, 0.5, 1, 2, and 4 g of chitosan were added as reinforcements. The solution was thoroughly mixed, then heated to a temperature of 70°C and stirred continuously till it started to gel, after which it was dried for 3 days. The developed composite was evaluated via physical, mechanical, and structural analyses. The results indicated that the sample with 0.5 g of chitosan reinforcement outperformed others with or without chitosan reinforcement, showing evidence of low water content, solubility, absorption, high tensile strength, and Young's modulus. The Fourier transform infrared (FTIR) spectroscopy results revealed that the chitosan amino group chemically reacted with the starch hydroxyl group, and a bio-blend was formed. From the scanning electron microscopy (SEM) test, the morphology of the composite surface showed homogeneity with no visible agglomerates, while the x-ray diffraction (XRD) results showed a sharp peak at 2θ of 29°. In addition, the thermogravimetric analysis (TGA) shows that the thermoplastic starch with 0.5 g of chitosan has the highest thermal stability at 750°C, leaving 19.63% residue. This study is significant as it enhances the application of bioplastics, encourages waste-to-wealth conversion, reduces waste generation, and promotes environmental sustainability.