Antibacterial activity of chitosan and its derivatives and their interaction mechanism with bacteria: Current state and perspectives

Fucoidan and its derivatives: From extraction to cutting-edge biomedical applications

Fucoidan, a sulfated polymeric carbohydrate isolated from various marine brown algae, has attracted the interest of biomedical scientists because of its unique structural features and extensive spectrum of biological activity. This review encompasses a comprehensive insight into fucoidan's extraction procedures, cross-linking strategies, chemical modifications, and biomedical applications. Advanced extraction methods, such as microwave-assisted and enzyme-assisted extraction, are emphasized to get high-quality fucoidan that has augmented bioactivity. Moreover, the production and role of fucoidan-based materials in drug delivery systems are investigated, with a focus on their potential for targeted therapies. The study also explores the strategies to improve fucoidan's bioavailability and mechanical properties via structural modifications, such as Sulfation, desulfation, methylation, benzoylation, sulfation, amination, acetylation and phosphorylation, and cross-linking with other polymers to form films, hydrogels, and nanocomposites. In addition, fucoidan's applications in drug delivery systems, tissue engineering, microneedles, and 3D bioprinting are discussed. By summarizing current research findings, this study seeks to comprehend the mechanisms underpinning fucoidan's therapeutic efficacy and its potential to develop robust biomaterials.

A chitosan-based fluorescence probe for the detection of nitrite in food samples

Polysaccharides, as a natural biomolecule, are abundantly available in nature and have good bioactivity. They contain several functional groups such as hydroxyl, carboxyl, and amino groups, which can exhibit different fluorescent property after modification. In this work, the chitosan (CS) was selected as a raw material and grafted with methotrexate (MTX) to prepare a nitrite sensor. The sensing material exhibited obvious aggregation-induced emission (AIE) properties and could react with nitrite under acidic conditions to form diazo compounds that could enhance fluorescence. This "enhanced-luminescent" mode fluorescence probe for nitrite (NO2-) displayed superior sensing performance, such as excellent sensitivity, good selectivity, a low detection limit (0.22 μM) and wide detection range from 0 to 120 μM. Moreover, this sensor was effectively applied to detect nitrite in sausage samples. Finally, CS-MTX also showed excellent biocompatibility, good water solubility and outstanding antibacterial performance against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). These results demonstrated that it may be a potent multifunctional material for nitrite detection and anti-bacteria in food industry.

Polymer Applied in Hydrogel Wound Dressing for Wound Healing: Modification/Functionalization Method and Design Strategies

Hydrogel wound dressings have emerged as a promising solution for wound healing due to their excellent mechanical and biochemical properties. Over recent years, there has been significant progress in expanding the variety of raw materials used for hydrogel formulation along with the development of advanced modification techniques and design approaches that enhance their performance. However, a comprehensive review encompassing diverse polymer modification strategies and design innovations for hydrogel dressings is still lacking in the literature. This review summarizes the use of natural polymers (e.g., chitosan, gelatin, sodium alginate, hyaluronic acid, and dextran) and synthetic polymers (e.g., poly(vinyl alcohol), polyethylene glycol, Pluronic F-127, poly(N-isopropylacrylamide), polyacrylamide, and polypeptides) in hydrogel wound dressings. We further explore the advantages and limitations of these polymers and discuss various modification strategies, including cationic modification, oxidative modification, double-bond modification, catechol modification, etc. The review also addresses design principles and synthesis methods, aligning polymer modifications with specific requirements in wound healing. Finally, we discuss future challenges and opportunities in the development of advanced hydrogel-based wound dressings.

Chitosan, derivatives, and its nanoparticles: Preparation, physicochemical properties, biological activities, and biomedical applications - A comprehensive review

Chitosan, derived from the deacetylation of chitin, is the second most widely used natural polymer, valued for its nontoxic, biocompatible, and biodegradable properties. These attributes have driven extensive research into diverse applications of chitosan and various derivatives. The key characteristics of chitosan muco-adhesion, permeability enhancement, drug release modulation, and antimicrobial activity are primarily due to its amino and hydroxyl groups. However, the limited solubility of raw chitosan in water and most organic solvents has posed challenges for broader application. Numerous chemically modified derivatives have been developed to address these inadequacies with improved physical and chemical properties. Among these derivatives, chitosan nanoparticles have emerged as versatile drug carriers with precise release kinetics and the capacity for targeted delivery, greatly enhancing drug efficacy and safety profiles for therapeutic applications. Due to these unique physicochemical properties, chitosan and chitosan nanoparticles are promising for improved drug delivery, vaccine administration, transplantation, gene therapy, and diagnostics. This review examines the physicochemical properties and bioactivities of chitosan and chitosan nanoparticles, emphasizing their broad-ranging biomedical applications.

Bio-fabrication of chitosan-stabilized magnesium oxide nanomaterials: Investigation of photocatalytic, in vitro cytotoxicity activities and apoptosis in oral squamous carcinoma cells

A bio-fabrication approach is a novel way to develop chitosan-stabilized magnesium oxide nanomaterials (cMgO-NMs). The process involves utilizing polymeric chitosan as the reducing and stabilizing agent. The characteristics of the developed cMgO-NMs were determined using various spectroscopical techniques. Fourier-transform infrared spectroscopy (FTIR) analysis revealed crucial functional groups, Ultraviolet-visible spectroscopy (UV-Vis) spectrum showed nanomaterial development with a peak at 358 nm, and powder X-ray diffraction (PXRD) pattern confirmed a pure cubic crystalline structure. Field emission scanning electron microscopy (FE-SEM) images depicted spherical shape, while energy dispersive X-ray analysis (EDX) confirmed Mg presence. The photocatalytic efficacy of these nanomaterials in degrading dye methylene blue (MB) was examined, and the findings demonstrated the remarkable proficiency of cMgO-NMs in breaking down the dye. The cytotoxic effects of cMgO-NMs were assessed for the first time on PCI-9A and PCI-13 cancer cell lines, yielding an IC50 value of 51 μg/mL and 42 μg/mL. The cMgO-NMs treated PCI-9A and PCI-13 cancer cells morphological changes were observed via acridine orange and ethidium bromide and DAPI staining assay, and apoptotic mode of cell death was examined through flow cytometry and comet assay. Polymeric chitosan proved effective in extensive cMgO-NMs production, showing potential as an anticancer drug, although requiring further preclinical development.

Antibacterial Properties of Polymeric Membranes Containing Doxycycline for Potential Applications in Foot Ulcer Treatment

Membranes made from biopolymers and loaded with doxycycline were investigated for potential use in the treatment of foot ulcers in diabetic patients. Carboxymethylcellulose (CMC) and chitosan (CHS) membranes were fabricated with 7% glycerol and 1% doxycycline (DOX). Their mechanical and physical properties, biocompatibility, and antimicrobial effects were thoroughly evaluated. The results demonstrated effective antibacterial activity against S. aureus and S. mutans. Based on the mechanical, physical, and hemolytic data, DOX-loaded CMC/CHS/G membranes show promise as a topical wound delivery system.

Evaluation of the inhibitory effect of different molecular weights chitosan on MRGPRX2-mediated mast cell degranulation and the pseudo-allergic reaction

OBJECTIVES

Chitosan is widely used in medicine to regulate immune responses in T cells and dendritic cells. However, research on the regulation of mast cells (MCs) is scarce. Mas-related G-protein-coupled receptor X2 (MRGPRX2) is a key receptor that mediates MC activation. However, the inhibitory effects of chitosan on MRGPRX2 activation have not yet been reported. The aim of this study was to determine whether chitosan inhibits MRGPRX2-mediated MC activation and the molecular weight of chitosan with the best inhibitory effect.

METHODS

Cytotoxic and activating effects of chitosan on LAD2 cells were evaluated in vitro. An in vitro MC degranulation reaction model and in vivo C48/80-induced local passive anaphylaxis mouse model were used to evaluate the inhibitory effect of chitosan on MRGPRX2 activation.

KEY FINDINGS

Chitosan inhibited MC degranulation mediated by MRGPRX2 in vitro and reduced histamine, β-hexosaminidase, and cytokine release. Chitosan inhibited local pseudo-allergy and inflammatory mediator release by inhibiting MRGPRX2-mediated MC activation. Moreover, low-molecular-weight chitosan exhibited superior inhibitory activity against MRGPRX2.

CONCLUSIONS

Chitosan inhibited MRGPRX2-mediated MC degranulation in vivo and in vitro. Low molecular weight chitosan has the potential to be developed as a functional drug or food to assist in the treatment of MRGPRX2-regulated diseases.

Adhesive transparent antimicrobial quaternized chitosan/oxidized dextran/polydopamine nanoparticle hydrogels for accelerated wound healing

Hydrogels possessing appropriate adhesion and antibacterial properties have emerged as promising dressings for expediting wound healing, while also providing the convenience of visualizing the wound site to accurately monitor the healing process. In this study, we incorporated oxidized and degraded polydopamine nanoparticles into quaternized chitosan/oxidized dextran hydrogel QOP series, resulting in enhanced transmittance exceeding 95 % and adhesion strengths reaching up to 19.4 kPa. Moreover, these hydrogels exhibit a well-defined porous structure, rapid gelling ability (<50 s), exceptional self-healing capacity, and a swelling rate surpassing 760 %. Furthermore, the QOP hydrogels demonstrate outstanding hemocompatibility (hemolysis rate < 3 %) and cytocompatibility (cell viability >100 %). In addition, they display potent inhibition against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Staphylococcus pasteuri and Escherichia coli, with bactericidal rates exceeded 90 %. The closure of MRSA-infected wounds along with H&E and Masson staining analysis revealed that QOP hydrogels can expedite wound healing by stimulating collagen deposition and facilitating angiogenesis.

Recent advances in nanomaterials and their mechanisms for infected wounds management

Wounds infected by bacteria pose a considerable challenge in the field of healthcare, particularly with the increasing prevalence of antibiotic-resistant pathogens. Traditional antibiotics often fail to achieve effective results due to limited penetration, resistance development, and inadequate local concentration at wound sites. These limitations necessitate the exploration of alternative strategies that can overcome the drawbacks of conventional therapies. Nanomaterials have emerged as a promising solution for tackling bacterial infections and facilitating wound healing, thanks to their distinct physicochemical characteristics and multifunctional capabilities. This review highlights the latest developments in nanomaterials that demonstrated enhanced antibacterial efficacy and improved wound healing outcomes. The antibacterial mechanisms of nanomaterials are varied, including ion release, chemodynamic therapy, photothermal/photodynamic therapy, electrostatic interactions, and delivery of antibacterial drugs, which not only combat bacterial infections but also address the challenges posed by biofilms and antibiotic resistance. Furthermore, these nanomaterials create an optimal environment for tissue regeneration, promoting faster wound closure. By leveraging the unique attributes of nanomaterials, there is a significant opportunity to revolutionize the management of infected wounds and markedly improve patient outcomes.

New insights into chitosan-Ag nanocomposites synthesis: Physicochemical aspects of formation, structure-bioactivity relationship and mechanism of antioxidant activity

Herein, a novel approach to the controlled formation of chitosan-Ag nanocomposites (NCs) with different structures and tunable chemical/biological properties was proposed. The chitosan-Ag NCs were obtained using hydrothermal synthesis and varying the concentrations of components. The hypothesis of chitosan-Ag NC synthesis using polysaccharide coils as a "microreactor" system was confirmed. A comparative analysis of the physicochemical characteristics of the NCs with single-core-shell and multi-core-shell structures was carried out, and the "structure-property" relationship was revealed. The obtained NCs exhibited excellent antiradical properties, comparable to the activity of phenolic acids: the IC50 values were 0.051, 0.022, and 0.019 mg/mL for CS7, CS5, and caffeic acid, respectively. A mechanism for the antiradical activity of chitosan-Ag NCs was discussed. The redox activity of the NCs was found to be 11.4 and 2.3 mg ABTS per 1 mg of Ag in CS5 and CS7, respectively. The proposed environmentally friendly one-pot, one-step synthesis of silver nanoparticles inside chitosan "microreactors" represents an innovative approach to designing hybrid materials with nanoscale control of desired structure and properties. These findings pave the way for further optimization of biopolymer‑silver nanostructures for various biomedical and industrial applications, including the design of a new type of hybrid catalysts such as nanozymes.

Inhibitory activity and mechanisms of chitosan against Fusarium avenaceum, a pathogen causing Angelica root rot disease

The polysaccharide chitosan possesses broad-spectrum antimicrobial properties and has proven effective in controlling various postharvest diseases in fruits. Nevertheless, the fundamental mechanisms underlying its action remain unclear. In this study, the antifungal effects of chitosan with different molecular weights against Fusarium avenaceum, a pathogen causing root rot in Angelica sinensis, were evaluated. Additionally, the potential mechanisms of these effects were explored at the microstructural and transcriptomic levels. Notably, low-molecular-weight chitosan (20 kDa) exhibited superior antifungal activity when compared to high-molecular-weight chitosan (500 kDa and 1000 kDa). The half-maximal inhibitory concentration (IC50) of 20, 500, and 1000 kDa chitosan were 0.2103, 0.2183, and 0.2707 g/L, respectively. Morphological and physiological experiments demonstrated that chitosan can inhibit the growth of F. avenaceum by decreasing spore germination, destroying mycelial morphology and microstructure, and promoting the release of intracellular electrolytes. RNA sequencing revealed considerable changes in the transcriptomic profile of F. avenaceum after chitosan treatment, with 2030 genes being differentially expressed. Subsequent KEGG pathway analysis demonstrated that genes associated with translation, human diseases, and transcription were upregulated in F. avenaceum after chitosan treatment. In contrast, genes associated with carbohydrate and amino acid metabolism, cellular processes, exogenous substance degradation and metabolism, and the metabolism of cofactors and vitamins were downregulated. Collectively, these results indicated that chitosan may influence the growth of F. avenaceum by disrupting protein biosynthesis and key metabolic pathways. These findings highlight the substantial potential of chitosan as an alternative agent for the management of fungal diseases in plants used in Chinese herbal medicine.

Simple preparation, big effect: Chitosan-based flame retardant towards simultaneous enhancement of flame retardancy, antibacterial, crystallization and mechanical properties of PLA

Preparing biobased flame retardants in a simple and fast path, while simultaneously imparting exceptional overall properties to PLA, poses a significant challenge. This study successfully synthesized a novel modified chitosan-based flame retardant, CPPA, through a simple one-step method and applied it to PLA. With the addition of just 10 wt% CPPA, the PLA-10%CPPA achieved UL-94 V-0 classification, while the limiting oxygen index (LOI) value increased to 30.3 %. Additionally, the peak heat release rate (pHRR) decreased from 494 kW/m2 to 407 kW/m2. The good compatibility between CPPA and PLA resulted in an 8.9 % improvement in the tensile performance of the PLA-CPPA composite. Furthermore, CPPA also enhanced the crystallization and antibacterial properties of PLA. This work provides a simple new approach for the development of multifunctional polymers.

Enhanced antibacterial and antibiofilm activities of quaternized ultra-highly deacetylated chitosan against multidrug-resistant bacteria

Multidrug-resistant (MDR) bacterial infections pose a severe threat to global public health and present significant challenges in the treatment of bacterial keratitis. The escalation of antimicrobial resistance (AMR) underscores the urgent need for alternative therapeutic strategies. In this study, we report the homogeneous synthesis of quaternized ultra-highly deacetylated chitosan (QUDCS) using a sequential acid-base combination approach. The optimized QUDCS-2 exhibits broad-spectrum antibacterial activity through a membrane-disruption mechanism driven by electrostatic, hydrogen bonding, and hydrophobic interactions, while maintaining low cytotoxicity and high selectivity. Compared to less deacetylated counterparts, QUDCS-2 demonstrates superior stability in enzyme-rich environments and effectively inhibits and eradicates mature biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Furthermore, QUDCS-2 exhibits a remarkable ability to prevent the development of antimicrobial resistance. In a mouse keratitis model, QUDCS-2 shows excellent biocompatibility and significant antibacterial efficacy, providing strong support for its potential as a long-term, effective antimicrobial agent.

Antibacterial and osteogenic properties of chitosan-polyethylene glycol nanofibre-coated 3D printed scaffold with vancomycin and insulin-like growth factor-1 release for bone repair

3D printing, as a layer-by-layer manufacturing technique, enables the customization of tissue engineering scaffolds. Surface modification of biomaterials is a beneficial approach to enhance the interaction with living cells and tissues. In this research, a polylactic acid/polyethylene glycol scaffold containing 30 % bredigite nanoparticles (PLA/PEG/B) was fabricated utilizing fused deposition modeling (FDM) 3D printing. To modify the surface properties and facilitate the loading and release of therapeutics, the scaffold was coated with chitosan-polyethylene glycol (CS-PEG) nanofibers incorporating vancomycin (V) and insulin-like growth factor-1 (IGF1). The characterization was conducted using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results demonstrated that the release of V (93.43 %) and IGF1 (95.86 %) from the fabricated scaffolds persisted for 28 days in a phosphate-buffered saline (PBS) solution. The release of V resulted in antibacterial activity against Staphylococcus aureus (S. aureus), forming an inhibition zone of 21.16 mm. Additionally, it was demonstrated that the release of IGF1 could counteract the adverse effect of V release on cell behavior, and enhance the adhesion and proliferation of MG63 cells. Preclinical in vivo studies conducted on a rat calvarial defect model validated that the bone repair was fully completed in the group treated with the fabricated scaffold within 8 weeks. Consequently, the scaffold designed in this study can serve as a versatile scaffold for achieving perfect repair of craniofacial defects.

Evaluation of the antimicrobial activity of chitosan- and curcumin-capped copper oxide nanostructures against multi-drug-resistant microorganisms

The emergence of multi-drug-resistant microorganisms presents a serious threat to infection control, for which new antimicrobial strategies are urgently needed. Herein, the antimicrobial activities of copper oxide nanoparticles capped with curcumin (Cur-CuO NPs) and copper oxide nanoparticles capped with chitosan (CS-CuO NPs) were investigated. They were prepared via the co-precipitation method. A total of 180 clinical ICU patients were found to have 70% Gram-negative and 30% Gram-positive isolates. Antimicrobial susceptibility testing indicated resistance of these isolates to 14 among the 21 tested antibiotics. Physicochemical properties of the curcumin-capped (Cur-CuO NPs) and chitosan-capped (CS-CuO NPs) copper oxide nanoparticles were identified using UV-vis spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta-potential (ζ), and Fourier transform infrared (FT-IR) spectroscopy. Cur-CuO- and CS-CuO-NPs exhibited potent antimicrobial efficacy, wherein CS-CuO NPs were found to possess a lower minimum inhibitory concentration (MIC) (3.9-15.6 μg mL-1) than Cur-CuO NPs (14.5-31.2 μg mL-1). Biocompatibility assay showed that Cur-CuO NPs were safer with an IC50 dose of 74.17 μg mL-1 than CS-CuO NPs with an IC50 dose of 41.01 μg mL-1. Results revealed that the Cur-CuO- and CS-CuO-NPs have the potential to be safely used as effective antimicrobial agents in clinical applications at low concentrations (6.25-12.5 μg mL-1).

Synthesis, characterization and computational study of chitosan-modified pH-responsive Mag@ZIF-8/CS drug delivery system loaded with magnolol for sustained drug release and synergistic antibacterial activity

ZIF-8 has strong potential for biomedical applications due to its excellent biocompatibility. In this study, 89.67 % of natural drug magnolol (Mag) was loaded in ZIF-8 to form Mag@ZIF-8, which was subsequently modified with chitosan (CS) to obtain Mag@ZIF-8/CS. The prepared materials were characterized using the UV-Vis spectroscopy, FTIR, XRD, DLS, SEM and TEM techniques. Thermal stability of materials was analyzed using Thermos Gravimetric Analysis system. PDI and Z-average hydrodynamic sizes of Mag@ZIF-8/CS and Mag@ZIF-8 were increased compared to ZIF-8. Similarly, Mag@ZIF-8 revealed higher zeta potential (+17.5 ± 2.3 mV) than ZIF-8 (+9.8 ± 0.5 mV), but Mag@ZIF-8/CS exposed -3.2 ± 0.9 mV, in water; however, at pH 4 it was changed to +5 mV. Pure ZIF-8 and Mag@ZIF-8 exhibited a hexagonal morphology, while Mag@ZIF-8/CS had a rotund, flat-like structure, with mean particle size of 101 nm, 123 nm and 343 nm, respectively. Density Functional Theory (DFT) analysis offered a deeper insight into the electronic properties and binding interactions of the composites. Under acidic conditions, drug release from Mag@ZIF-8 was higher (86.4 %) and faster than from Mag@ZIF-8/CS (74 %), when tested at physiological pH 7.4 and 37 °C. This, suggests that CS modification of Mag@ZIF-8 is crucial for achieving prolonged and sustained drug release. Mag@ZIF-8 and Mag@ZIF-8/CS depicted a two-fold increase in antibacterial activity against E. coli and S. aureus, demonstrating a synergistic effect. The MIC value for E. coli and S. aureus were, 35 μg/mL and 20 μg/mL, respectively, confirming the enhanced antibacterial efficacy of the composites. Molecular docking analysis provided deeper insights into the binding interactions between the materials and the E. coli protein 5AZC.

Water-soluble chlorogenic acid-chitosan and polydatin-chitosan conjugates: antibacterial activity and inhibition of lipid and protein oxidation

BACKGROUND

Chitosan (CS), an abundant alkaline polysaccharide, is valued for its biocompatibility, non-toxicity, and antibacterial properties. However, its limited solubility and modest antioxidant activity constrain its utility. Grafting polyphenols onto chitosan through the use of grafting reactions can enhance both the solubility and bioactivity of chitosan. Among the techniques employed, the free radical grafting method is favored for its simplicity, environmental sustainability, and its effectiveness in preserving biological activity.

RESULTS

In this study, chlorogenic acid (CGA) and polydatin (PLD) were conjugated successfully to chitosan by a Vc/H2O2 redox system. Analytical techniques such as ultraviolet-visible (UV-visible) spectroscopy, fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and proton nuclear magnetic resonance (1H NMR) were employed to confirm the formation of covalent bonding between the polyphenol molecules and the chitosan backbone. The novel conjugates displayed superior antioxidant properties in comparison with pristine chitosan, as evidenced by their enhanced 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical, and hydroxyl radical scavenging capacities, and Fe2+ reducing power. Both CGA-CS and PLA-CS exhibited excellent lipid and protein oxidation inhibition capabilities. Furthermore, the conjugates were shown to have significant antibacterial effects against four common pathogenic bacteria: Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas putida, and Staphylococcus aureus (P < 0.05).

CONCLUSION

The newly synthesized water-soluble polyphenol-chitosan conjugates demonstrated remarkable biological activity, particularly CGA-CS. This study offers new insights and a strong theoretical foundation for developing natural food preservation materials with potential applications in the food industry. © 2024 Society of Chemical Industry.

Effect of chitosan on buck semen quality and semen plasma metabolites during low-temperature storage

Background

Optimizing buck semen preservation techniques can significantly advance the goat industry. This study aimed to investigate the effects of chitosan on sperm quality and seminal plasma metabolite profiles in bucks during low-temperature storage at 4°C.

Results

The results showed that when 0.2 mg/mL chitosan was added to semen dilution, sperm viability and antioxidant capacity were highest and significantly higher than the control group (p < 0.05). Sperm viability decreased progressively with increasing storage time at 4°C. However, on day 5, sperm viability was significantly higher in all groups where chitosan was added to the semen dilutions than in the control group (p < 0.05). A total of 23 classes of metabolites were detected in the non-targeted metabolism group of seminal plasma. The metabolite caused by chitosan mainly included fatty acyls, phospholipids, amino acids and organic acids. Most differential metabolites in fatty acyls and glycerophospholipids in chitosan-treated semen were decreased and enriched in the anabolic pathway of unsaturated fatty acids. Additionally, several oligopeptides showed correlations with sperm quality.

Conclusion

These results suggest that adding 0.2 mg/mL chitosan to semen diluent successfully prolongs the low-temperature preservation of semen mainly by altering the anabolism of lipids and amino acids. This provides theoretical support and practical reference for the applying chitosan in the low-temperature preservation of buck semen.

Inherent antibacterial properties of mannose-containing polynorbornene glycomaterials

Monosaccharides are typically employed as targeting ligands in antimicrobial polymers, yet we discovered that certain glycopolymers prepared by ring-opening metathesis polymerization display inherent antibacterial activity, despite lacking conventional antimicrobial groups. Mannose-functionalized polymers proved potent against Escherichia coli, which could be rescued by adding excess mannose to the growth medium.

Versatile nanomaterials used in combatting biofilm infections

Microbial infections are a pressing global health issue, exacerbated by the rise of antibiotic-resistant bacteria due to widespread antibiotic overuse. This resistance diminishes the effectiveness of current treatments, intensifying the need for new antimicrobial agents and innovative drug delivery strategies. Nanotechnology presents promising solutions, leveraging the unique properties of nanomaterials such as tunable optical and electronic characteristics, nanoscale size, and high surface-to-volume ratios. These features enhance their effectiveness as innovative antimicrobial agents and versatile drug delivery systems. This minireview classifies antimicrobial nanomaterials into four categories based on their mechanisms of action: thermal generation, reactive oxygen species generation, gas generation, and nanocarrier systems such as liposomes, polymersomes, and metal-organic frameworks. Uniquely, this review integrates a comparative analysis of these mechanisms, highlighting their relative advantages, limitations, and applications across diverse microbial targets. Additionally, it identifies emerging trends in the field, providing a forward-looking perspective on how recent advancements in nanotechnology can be leveraged to address unmet clinical needs. Finally, this article discusses future directions and emerging opportunities in antimicrobial nanotechnology.

Chitosan fabricated silver nitroprusside nanocomposites prepared for enhanced antibacterial and cytocompatibility applications through controlled release of metal ions and nitric oxide

Silver nitroprusside complex nanoparticles (AgN NPs) have garnered significant attention for their antimicrobial properties. However, challenges such as toxicity and limited biocompatibility often hinder their practical applications. Therefore, this study introduces a combined approach to fabricating AgN NPs with chitosan (CS), resulting in CS-AgN nanocomposites (CS-AgN NCs) with cytocompatibility. AgN NPs exhibited a distinct cubic morphology with a mean size of 52.88 ± 15.45 nm, while CS-AgN NCs showed a smaller, spherical, and elongated structure. The incorporation of CS led to significant changes in AgN NPs, including a reduction in the zeta potential from -46.63 ± 1.25 mV to -13.0 ± 2.12 mV and alterations in crystallinity. A key finding was that nitric oxide (NO) release was highly pH-dependent, which could offer targeted therapeutic potential. Both nano systems demonstrated potent antibacterial effects, with minimum inhibitory concentrations (MICs) as low as 6.25 μg/mL against E. coli, alongside strong biofilm inhibition (≥80 % at 12.5-25 μg/mL). The CS-AgN NCs also exhibited superior antioxidant activity compared to AgN NPs without compromising cell viability or causing hemolysis, and low toxicity to Artemia salina, making them promising candidates for biomedical applications. This work highlights the unique interplay between AgN NPs and CS, offering insights into their potential for next-generation antimicrobial therapies.

Fabrication and characterization of chitosan-based bionanocomposite coating reinforced with TiO2 nanoparticles and carbon quantum dots for enhanced antimicrobial efficacy

Polymer-based nanocomposite coatings that are enhanced with nanoparticles have gained recognition as effective materials for antibacterial purposes, providing improved durability and biocidal effectiveness. This research introduces an innovative chitosan-based polymer nanocomposite, enhanced with titanium oxide nanopowders and carbon quantum dots. The material was synthesized via the sol-gel process and applied to 316L stainless steel through dip-coating. Structural and morphological properties, including crystal structure, microstructure, elemental dispersion, particle size distribution, chemical composition, and surface morphology, were thoroughly characterized. The results demonstrated that carbon quantum dots and titanium oxide nanopowders were uniformly dispersed within the chitosan matrix, forming a homogeneous, non-agglomerated coating. The antibacterial efficacy of the synthesized samples against 7 different Gram-positive and Gram-negative bacteria was assessed through disk diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) tests. The results confirmed the antibacterial activity of synthesized samples against most of the bacterial pathogens tested but exhibited stronger antibacterial effects on Gram-negative bacteria compared to Gram-positive bacteria. The largest inhibition zones, measuring 21 mm and 16 mm, were observed for Pseudomonas and E. coli for titanium dioxide nanoparticles and the final nanocomposite, respectively. Additionally, the MIC and MBC values for all 7 bacteria were determined.

Preparation of poly(l-lactic acid) antibacterial film based on surface grafting of modified chitosan and its preservation effect on chilled beef

Chilled beef is a perishable food product. Due to the broad-spectrum antimicrobial properties of chitosan, and the biodegradability of PLLA, chitosan and PLLA are introduced double bonding groups to obtain Chitosan-graft-Glycidyl methacrylate (Cs-g-GMA) and Poly(L-lactic acid)-co-poly(butylene itaconate) (PLBI), respectively. Cs-g-GMA is then grafted onto the surface of PLBI films by UV curing to produce PLBI/Cs-g-GMA films with non-migratory, broad-spectrum antimicrobial, biodegradable, and possess good oxygen barrier properties, compared to current antimicrobial films. Antimicrobial tests in vitro confirmed that PLBI/Cs-g-GMA film could effectively inhibit the growth and reproduction of P. fluorescens, S. aureus, and E. coli. The PLBI/Cs-g-GMA films were further used for the packaging of chilled beef during 15 days of refrigerated storage. The microbiological (total viable counts (TVC), microbial diversity analysis), physicochemical (pH, total volatile basic nitrogen (TVB-N), drip loss, color) and sensory of beef were measured to evaluate the preservation effect. The results showed that PLBI/Cs-g-GMA films can significantly inhibit Pseudomonas and Aeromonas at the phylum and genus levels, respectively. Based on the good results of the preservation index, PLBI/Cs-g-GMA film could delay the quality deterioration of chilled beef by 3 to 9 days, suggesting that its considerable prospects for maintaining the storage quality of chilled beef.

Improved Adhesion and Biocompatibility of Chitosan-Coated Super-Hydrophilic PVC Polymer Substrates for Urothelial Catheters

Chitosan is a water-soluble polysaccharide with good adherence to negatively charged surfaces and reported antimicrobial and anti-inflammatory properties. Coating the surfaces of medical devices with chitosan is a promising strategy for harnessing these benefits. However, the surface properties of commercial polymers need to be altered to enable the bonding of thin chitosan films. In this study, the adhesion of chitosan onto plasma-treated polyvinyl chloride (PVC) and the metabolic activity of urothelial cells on chitosan-coated medical-grade PVC used for the synthesis of urinary catheters were evaluated. To improve the adhesion of chitosan onto the PVC catheters, PVC samples were made "super-hydrophilic". PVC substrates were briefly treated with a powerful hydrogen plasma and weakly ionised oxygen plasma afterglow to obtain a chlorine-free surface film, which was rich in oxygen functional groups, followed by incubation of the plasma-treated substrates in an aqueous solution of chitosan. Then, urothelial RT4 cells were seeded on the treated and untreated PVC substrates, and their metabolic activity, confluency, and cell morphology were examined. X-ray photoelectron spectroscopy was used to measure the nitrogen concentration, which corresponded to the chitosan concentration on the substrate. The results showed that the substrates were uniformly covered by a thin layer of chitosan only on plasma-treated surfaces and not on untreated surfaces. Moreover, the chitosan coating provided a stimulated environment for cell adhesion and growth. In conclusion, the chitosan-coated super-hydrophilic PVC substrate shows potential to improve the overall performance and safety of medical devices such as urinary catheters.

Disrupting Biofilms on Human Kidney Stones-A Path Toward Reducing Infectious Complications During Stone Surgery

Kidney stones are a common disorder associated with significant morbidity and often requires surgical intervention. Pathogenic bacteria are found in almost 40% of stones, where they form biofilms that are protected from systemic antibiotic treatments. Stone surgeries disperse biofilms resulting in up to 30% of patients developing postoperative urinary tract infections and 15% developing sepsis. This work is based on the hypothesis that chitosan, an antimicrobial polymer, can eradicate bacterial biofilms present in the stone and potentially serve as an adjunct to irrigation during stone surgery. First, fresh patient-derived kidney stone fragments (n = 56) are collected from stone surgeries. A total of 32% of stones are colonized, predominantly with Enterococcus faecalis, Escherichia coli, and Proteus mirabilis. A short, clinically relevant, chitosan treatment reduces the bacterial burden on colonized stones by over 90% in all specimens tested, regardless of stone composition and bacterial strain. To assess this approach toxicity, ex vivo human ureters and in vivo porcine bladders are exposed to topical chitosan irrigation. No toxic or pathological abnormalities other than urothelial exfoliation are noted. In conclusion, chitosan effectively disrupts kidney stone-associated bacterial biofilms with minimal urothelial toxicity and may provide an effective and safe approach to reducing postoperative complications.

Implantable Dental Barrier Membranes as Regenerative Medicine in Dentistry: A Comprehensive Review

BACKGROUND

Periodontitis and bone loss in the maxillofacial and dental areas pose considerable challenges for both functional and aesthetic outcomes. To date, implantable dental barrier membranes, designed to prevent epithelial migration into defects and create a favorable environment for targeted cells, have garnered significant interest from researchers. Consequently, a variety of materials and fabrication methods have been explored in extensive research on regenerative dental barrier membranes.

METHODS

This review focuses on dental barrier membranes, summarizing the various biomaterials used in membrane manufacturing, fabrication methods, and state-of-the-art applications for dental tissue regeneration. Based on a discussion of the pros and cons of current membrane strategies, future research directions for improved membrane designs are proposed.

RESULTS AND CONCLUSION

To endow dental membranes with various biological properties that accommodate different clinical situations, numerous biomaterials and manufacturing methods have been proposed. These approaches provide theoretical support and hold promise for advancements in dental tissue regeneration.

Wool Fabric with an Improved Durable Biological Resistance Using a Coumarin Derivative

Wool is the most widely used proteinic natural fiber in the clothing industry by virtue of its versatile properties. Unfortunately, wool, as a natural fiber, is more susceptible to attack by microorganisms and moths, which may cause harm to the fiber and human health. That is why the antimicrobial and mothproof finishing of natural textiles is of prime importance to the textile and clothing industry. Herein, wool fabric was treated with the synthesized 6-aminocoumarin adopting the pad-dry-cure technique with or without a cross-linker. The treated wool fabric was evaluated for its antimicrobial activity against Staphylococcus aureus and Escherichia coli. The treated wool fabric was also tested for moth-proofing performance against Tineola Bisselliella through assessing the fabric weight loss. Various analyses were conducted to assign the alteration in the structure of the treated wool fibers, viz., urea-bisulfite solubility, carboxylic content, Fourier transform infrared spectroscopy, and X-ray diffraction pattern (XRD). Scanning electron microscopy displayed the surface of wool fabric before and after treatment. Some physical and mechanical properties were also assessed. Results revealed that treated wool fabric showed a bacterial resistance to Gram +ve and Gram -ve bacteria, in addition to its improved resistance to moth larvae attack without deterioration in the fabric's inherent properties.

Nanochitin From Crab Shells: Production, Chemical Modification, Composite Materials, and Physiological Functions

Large quantities of crab shells are generated in food-processing plants. In this review, the authors summarize a series of research findings on the production of nanochitin, its physical properties, chemical modifications, and functions, which have not been fully addressed in existing literature. Nanochitin, which has a width of 10 nm, is derived from chitin, the main component of crab shells, using a technology similar to that used to produce nanocellulose from wood. Unlike conventional chitin, nanochitin is well dispersed in water, making it easy to mold and process into various products for different applications. They can also be modified for specific uses through processes such as acylation and etherification to enhance their physical properties and add functionality. Nanochitin, which are known for their exceptional mechanical strength, can be blended with resins to create composite films with improved strength and elasticity. These films maintain the transparency of the resin, reduce its thermal expansion, and offer reinforcement. Chitin and its derivative chitosan are used as wound dressings, hemostatic agents, and health foods. Nanochitin and its deacetyl derivatives have diverse functions such as topical medicine for the skin, ingestion as a health food, and use as pesticides or fertilizers for plants.

Carboxymethyl chitosan/alendronate sodium/Sr2+ modified TiO2 nanotube arrays enhancing osteogenic activity and antibacterial property

Titanium and its alloys are widely used as orthopedic implants owing to their good mechanical properties and excellent corrosion resistance. However, the insufficient osteogenic activity and antibacterial properties hinder their clinical applications. To address these issues, TiO2 nanotube arrays (TNT) were first fabricated on the TA2 alloy surface via an anodizing technique, and strontium ions (Sr2+) were then loaded by hydrothermal reaction (TNT + Sr) and annealing treatment (TNT + A). Subsequently, the polydopamine layer (TNT + PDA) was constructed to immobilize the carboxymethyl chitosan and alendronate sodium (TNT + CA) mixture. The prepared coatings were thoroughly characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectrometer (XPS), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffractometer (XRD), and water contact angle measurement. The results confirmed that Sr2+ ions, polydopamine, and carboxymethyl chitosan/alendronate sodium were successfully immobilized on the nanotubes. The coating of TNT + CA significantly enhanced the hydrophilicity, and effectively delayed the release of Sr2+ and alendronate. The TNT + CA coating significantly promoted osteoblast adhesion and proliferation, and up-regulated the expressions of alkaline phosphatase (ALP), osteocalcin (OCN), and osteoblast-specific transcription factor (RUNX2). TNT + CA was able to rapidly induce in situ hydroxyapatite deposition from the simulated body fluid (SBF). Moreover, TNT + CA coating showed inhibition against Escherichia coli and Staphylococcus aureus (especially against Escherichia coli). The prepared TNT + CA coating provides a novel strategy for enhancing bone affinity, improving osteoblast behaviors, and antibacterial properties of titanium-based biomaterials.

Thermo-responsive/anti-biofouling chitosan hydrogel beads in situ decorated with silver nanoparticles for water disinfection

The development of a sustainable and eco-friendly silver-based hybrid nanocomposite for safe and efficient point-of-use (POU) water disinfection remains a challenge. Herein, a simple and facile approach was proposed for the in situ immobilization of silver nanoparticles (AgNPs) on chitosan-g-poly (sulfobetaine methacrylate) (CS-g-PSBMA) hydrogel beads, which have been achieved via graft copolymerization of sulfobetaine methacrylate along the chitosan chains followed by a drop method. The AgNPs-decorated CS-g-PSBMA hydrogel beads were characterized and their bactericidal efficacy towards Escherichia coli was evaluated concurrently with their anti-biofouling behaviors. The results indicated that the grafted PSBMA hydrogels on CS would not only enhance the immobilization of more AgNPs (122.63 mg/g material), but also restricted the silver release (only 0.015 % after the 14th day of incubation), which surpassed numerous other AgNPs-based nanocomposites for water disinfection. Moreover, the release of silver can be modulated by altering the temperature due to the thermosensitivity of PSBMA, and the maximum concentration of silver leaching in the effluent was 33.1-52.3 μg/L at 25-60 °C. Importantly, the synthesized AgNPs-based CS-g-PSBMA can exert both exceptional bactericidal and superior anti-biofouling capabilities as well as reusability features, indicating sustained antibacterial effectiveness and significant potential for practical applications in water disinfection.

Eutectic Solvents Based on Matrine and Fatty Acids as Solubility and Stability Enhancers of Curcumin

Eutectic solvents (ESs) have shown great efficiency on increasing the solubility, stability, and bioactivity of active pharmaceutical ingredients (APIs) in recent research studies. Curcumin is an important API driven from natural plants, which displayed a series of biofunctions like antibacterials, anti-inflammatory, and anticancer activities etc. However, its poor water solubility and stability hindered its further clinic application. Herein, a series of novel ESs based on matrine and fatty acids (i.e., octanoic acid, decanoic acid, and lauric acid) were developed. The phase behavior and cytotoxicity of these ESs were investigated. Moreover, the prepared ESs displayed excellent ability on enhancing the solubility of curcumin with the highest solubility being 28 mg/mL at 298 K, which was nearly 50000-fold than that in water. The curcumin showed high stability in ESs, where only 10% of curcumin decomposed under light irradiation for 6 h. Furthermore, biofilms based on these ES solutions of curcumin have been prepared and displayed high antioxidant and antibacterial activities. To summarize, the prepared eutectic systems provide a new strategy for further application of curcumin.

Exploring the Potential of Chitosan-Phytochemical Composites in Preventing the Contamination of Antibiotic-Resistant Bacteria on Food Surfaces: A Review

The escalating presence of antibiotic-resistant bacteria (ARB) in food systems presents a pressing challenge, particularly in preventing contamination and ensuring food safety. Traditional sanitation methods, such as cooking and chemical disinfectants, provide effective means to reduce ARB, yet there is a growing need for additional preventive measures directly on food surfaces. This review explores the potential of chitosan-phytochemical composites (CPCs) as surface coatings to prevent the initial contamination of food by ARB, thereby offering a novel complementary approach to conventional food safety practices. Chitosan, combined with active plant-derived metabolites (phytochemicals), forms composites with notable antibacterial and antioxidant properties that enhance its protective effects. We examine CPC synthesis methodologies, including chemical modifications, free radical-induced grafting, and enzyme-mediated techniques, which enhance the stability and activity of CPCs against ARB. Highlighting recent findings on CPCs' antibacterial efficacy through minimum inhibitory concentrations (MIC) and zones of inhibition, this review underscores its potential to reduce ARB contamination risks on food surfaces, particularly in seafood, meat, and postharvest products. The insights provided here aim to encourage future strategies leveraging CPCs as a preventative surface treatment to mitigate ARB in food production and processing environments.

Chitosan and Its Nanoparticles: A Multifaceted Approach to Antibacterial Applications

Chitosan, a multifaceted amino polysaccharide biopolymer derived from chitin, has extensive antibacterial efficacy against diverse pathogenic microorganisms, including both Gram-negative and Gram-positive bacteria, in addition to fungi. Over the course of the last several decades, chitosan nanoparticles (NPs), which are polymeric and bio-based, have garnered a great deal of interest as efficient antibacterial agents. This is mostly due to the fact that they are used in a wide variety of applications, including medical treatments, food, chemicals, and agricultural products. Within the context of the antibacterial mechanism of chitosan and chitosan NPs, we present a review that provides an overview of the synthesis methods, including novel procedures, and compiles the applications that have been developed in the field of biomedicine. These applications include wound healing, drug delivery, dental treatment, water purification, agriculture, and food preservation. In addition to this, we focus on the mechanisms of action and the factors that determine the antibacterial activity of chitosan and its derivatives. In conjunction with this line of inquiry, researchers are strongly urged to concentrate their efforts on developing novel and ground-breaking applications of chitosan NPs.

Chitosan-Based Schiff Bases (CSBs) and Their Metal Complexes: Promising Antimicrobial Agents

The scientific interest in the chemical modification of chitosan to increase its solubility and application has led to its conjugation with Schiff bases, which are interesting scaffolds endowed with diverse biological properties. The resultant chitosan-based Schiff bases (CSBs) are widely studied in scientific literature due to the myriad of activities exerted, both catalytic and biological, including anticancer, anti-inflammatory, antioxidant, and especially antimicrobial ones. Antimicrobial resistance (AMR) is one of the major public health challenges of the twenty-first century because it represents a threat to the prevention and treatment of a growing number of bacterial, parasitic, viral, and fungal infections that are no longer treatable with the available drugs. Thus, in this review, we present a brief outline of the biological activities of CSBs as well as their complexes with metals, with a particular focus on the recent literature regarding the antimicrobial effect of these captivating derivatives.

Can polymeric nanofibers effectively preserve and deliver live therapeutic bacteria?

Probiotics and live therapeutic bacteria (LTB), their strictly regulated therapeutic counterpart, are increasingly important in treating and preventing biofilm-related diseases. This necessitates new approaches to (i) preserve bacterial viability during manufacturing and storage and (ii) incorporate LTB into delivery systems for enhanced therapeutic efficacy. This review explores advances in probiotic and LTB product development, focusing on preservation, protection, and improved delivery. Preservation of bacteria can be achieved by drying methods that decelerate metabolism. These methods introduce stresses affecting viability which can be mitigated with suitable excipients like polymeric or low molecular weight stabilizers. The review emphasizes the incorporation of LTB into polymer-based nanofibers via electrospinning, enabling simultaneous drying, encapsulation, and delivery system production. Optimization of bacterial survival during electrospinning and storage is discussed, as well as controlled LTB release achievable through formulation design using gel-forming, gastroprotective, mucoadhesive, and pH-responsive polymers. Evaluation of the presence of the actual therapeutic strains, bacterial viability and activity by CFU enumeration or alternative analytical techniques is presented as a key aspect of developing effective and safe formulations with LTB. This review offers insights into designing delivery systems, especially polymeric nanofibers, for preservation and delivery of LTB, guiding readers in developing innovative biotherapeutic delivery systems.

Synergistic effects of incorporated additives in multifunctional dressings for chronic wound healing: An updated comprehensive review

Detailed reviewing of the complicated process of wound healing reveals that it resembles an orchestrated symphony via a precise and calculated collaboration of relevant cells at the wound site. The domino-like function of various cytokines, chemokines, growth factors and small biological molecules such as antibacterial peptides all come together to successfully execute the wound healing process. Therefore, it appears that the use of a wound dressing containing only a single additive with specific properties and capabilities may not be particularly effective in treating the complex conditions that are usual in the environment of chronic wounds. The use of multifunctional dressings incorporating various additives has shown promising results in enhancing wound healing processes. This comprehensive review article explores the synergistic effects of integrated additives in such dressings, aiming to provide an updated understanding of their combined therapeutic potential. By analysing recent advancements and research findings, this review sheds light on the intricate interactions between different additives, their mechanisms of action and their cumulative impact on wound healing outcomes. Moreover, the review discusses the importance of utilising combined therapies in wound care and highlights the potential future directions and implications for research and clinical practice in the field of wound healing management.

Chitosan Poly(vinyl alcohol) Methacrylate Hydrogels for Tissue Engineering Scaffolds

A major challenge in tissue engineering scaffolds is controlling scaffold degradation rates during healing while maintaining mechanical properties to support tissue formation. Hydrogels are three-dimensional matrices that are widely applied as tissue scaffolds based on their unique properties that can mimic the extracellular matrix. In this study, we develop a hybrid natural/synthetic hydrogel platform to tune the properties for tissue engineering scaffold applications. We modified chitosan and poly(vinyl alcohol) (PVA) with photo-cross-linkable methacrylate functional groups and then synthesized a library of chitosan PVA methacrylate hydrogels (ChiPVAMA) with two different photoinitiators, Irgacure 2959 (I2959) and lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP). ChiPVAMA hydrogels showed tunability in degradation rates and mechanical properties based on both the polymer content and photoinitiator type. This tunability could enable their application in a range of tissue scaffold applications. In a 2D scratch wound healing assay, all hydrogel samples induced faster wound closure compared to a gauze clinical wound dressing control. NIH/3T3 cells encapsulated in hydrogels showed a high viability (∼92%) over 14 days, demonstrating the capacity of this system as a supportive cell scaffold. In addition, hydrogels containing a higher chitosan content demonstrated a high antibacterial capacity. Overall, ChiPVAMA hydrogels provide a potential tissue engineering scaffold that is tunable, degradable, and suitable for cell growth.

Antifungal Chitosan Nanocomposites-A New Perspective for Extending Food Storage

Chitosan, a biopolymer derived from chitin, exhibits significant antifungal properties, making it a valuable compound for various applications in agriculture food preservation, and biomedicine. The present study aimed to assess the antifungal properties of chitosan-modified films using sol-gel derivatives (CS:ZnO) or graphene-filled chitosan, (CS:GO and CS:rGO) against two strains of fungi that are the most common cause of food spoilage: Aspergillus flavus ATCC 9643 and Penicillium expansum DSM 1282. The results indicate important differences in the antifungal activity of native chitosan films and zinc oxide-modified chitosan films. CS:ZnO nanocomposites (2:1 and 5:1) completely inhibited spore germination of the two tested fungal strains. Furthermore, a decrease in spore viability was observed after exposure to CS:Zn films. Significant differences in the permeability of cell envelopes were observed in the A. flavus. Moreover, the genotoxicity of the materials against two cell lines, human BJ fibroblasts and human KERTr keratinocytes, was investigated. Our studies showed that the tested nanocomposites did not exhibit genotoxicity towards human skin fibroblasts, and significant damage in the DNA of keratinocytes treated with CS:ZnO composites. Nanocomposites based on chitosan may help reduce synthetic fungicides and contribute to sustainable food production and food preservation practices.

Biopolymeric Inhalable Dry Powders for Pulmonary Drug Delivery

Natural and synthetic biopolymers are gaining popularity in the development of inhaled drug formulations. Their highly tunable properties and ability to sustain drug release allow for the incorporation of attributes not achieved in dry powder inhaler formulations composed only of micronized drugs, standard excipients, and/or carriers. There are multiple physiological barriers to the penetration of inhaled drugs to the epithelial surface, such as the periciliary layer mucus mesh, pulmonary macrophages, and inflammation and mucus compositional changes resulting from respiratory diseases. Biopolymers may facilitate transport to the epithelial surface despite such barriers. A variety of categories of biopolymers have been assessed for their potential in inhaled drug formulations throughout the research literature, ranging from natural biopolymers (e.g., chitosan, alginate, hyaluronic acid) to those synthesized in a laboratory setting (e.g., polycaprolactone, poly(lactic-co-glycolic acid)) with varying structures and compositions. To date, no biopolymers have been approved as a commercial dry powder inhaler product. However, advances may be possible in the treatment of respiratory diseases and infections upon further investigation and evaluation. Herein, this review will provide a thorough foundation of reported research utilizing biopolymers in dry powder inhaler formulations. Furthermore, insight and considerations for the future development of dry powder formulations will be proposed.

Chitosan-gelatin composite hydrogel antibacterial film for food packaging

Antibacterial hydrogel film can serve as food packaging materials to prevent bacteria growth and spread, thereby extending shelf life and improve food safety. In this study, an efficient antibacterial hydrogel film (CLG) was prepared with chitosan, lysine, and gelatin. The light transmission of the CLG hydrogel film was over 80 % in the visible region, facilitating the observation of chicken breast storage conditions. Additionally, the swelling ratios of the hydrogel films decreased with increasing gelatin concentration, from 145.7 g/g (CLG1) to 92.6 g/g (CLG2) and 81.5 g/g (CLG3). This reduction was attributed to the denser network structure formed by the interaction between gelatin and the CL polymer. The Scanning Electron Microscopy (SEM) showed that the water-absorbed CLG hydrogel had a unique sponge shape. Moreover, the CLG hydrogel film exhibits high antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In a practical storage experiment, the CLG hydrogel film extended the shelf life of chicken breast by up to 4 days compared to untreated samples, while effectively reducing total volatile basic nitrogen (TVB-N) levels. This hydrogel film is expected to become a promising food packaging material.

Dynamic responses of the inter-microbial synergism and thermodynamic conditions attribute to the inhibition-and-relief effects of chitosan towards anaerobic digestion

Wide commercial applications of chitosan in food preservation and green packaging fields inevitably lead to the universal existence in food, as well as the food waste (FW) processing system. However, whether and how the chitosan, a class of biomacromolecule substances, lead to dysfunction of anaerobic digestion (AD) process of FW remains less understood. Herein, chitosan exhibited an inhibition-and-relief effect with the AD process proceeding, and 80 mg/g-FW of chitosan decreased the net methane yield of FW by 24.7 %. The dynamic effect was ascribed to the varied fates of chitosan and the coupling biotic/abiotic influencing on multi-steps. Chitosan enhanced substrate flocs agglomeration, restraining the release of organics to liquid phase and reducing the binding affinity to enzymes. Among the various microorganisms involved in different steps, chitosan severely inhibited aceticlastic and hydrogenotrophic methanogen at the levels of microbial abundance, activity and function. Genome-centric metagenomics analyses revealed that transient chitosan decreased the coenzyme-based synergism of various microbial taxa involved in acetic acid generation/consumption metabolisms, including syntrophic propionate-oxidizing bacteria, syntrophic butyrate-oxidizing bacteria and methanogen. With the elimination of chitosan, these inhibitions were relieved, and the accumulated acetic acid and the more favorable thermodynamic conditions finally attributed to the recovery of AD performance.

All-aqueous microfluidic fabrication of calcium alginate/alkylated chitosan core-shell microparticles with time-sequential functions for promoting whole-stage wound healing

Wound healing comprises a series of complex physiological processes, including hemostasis, inflammation, cell proliferation, and tissue remodeling. Designing new functional biomaterials by biological macromolecules with tailored therapeutic effects to precisely match the unique requirements of each stage is cherished but rarely discussed. Here, we employ all-aqueous microfluidics to fabricate multifunctional core-shell microparticles aimed at promoting whole-stage wound healing. These microparticles feature a core comprising calcium alginate, cellulose nanocrystals and epidermal growth factor, surrounded by a shell made of alkylated chitosan, alginate, and ciprofloxacin (EGF + CNC@Ca-ALG/CIP@ACS core-shell microparticles, D-CSMP). Response surface methodology (RSM) with a combination of central composite rotatable design (CCRD) is used to meticulously optimize the fabrication processes, endowing the resulting D-CSMP with superior capabilities for efficiently encapsulating and controlled releasing CIP and EGF tailored to each stage aligning the healing timeline. The developed D-CSMP demonstrate notable time-sequential functionalities, including promoting blood coagulation, enhancing hemostasis, and exerting antibacterial effects. Furthermore, in a skin injury model, D-CSMP significantly expedite and enhance the chronic wound healing process. In conclusion, our core-shell microparticles with notable time-sequential functions present a versatile and robust approach for wound treatment and related biomedical applications.

A Systematic Review and Meta-Analysis to Evaluate the Effects of Chitosan on Obesity Indicators

Chitosan, a commonly used dietary supplement, is believed to have the potential to decrease body weight by binding to dietary fats and decreasing their absorption. However, due to conflicting results from various studies, this review aimed to investigate the effects of chitosan supplementation on obesity indicators in adults. To find appropriate randomized clinical trials (RCTs), a thorough search was conducted across electronic databases like PubMed/Medline, Scopus, and ISI Web of Science. The random-effects method was employed to combine the data, and the outcomes were presented as the weighted mean difference (WMD) with 95% confidence intervals (CIs). In total, 19 RCTs with 21 effect sizes were included in the meta-analysis. The combined analysis showed that chitosan supplementation significantly reduced body weight (WMD = -0.79 kg; 95% CI, -1.30 to -0.29; p = 0.002) and body-fat percentage (BFP) (WMD = -0.41%; 95% CI, -0.50 to -0.32; p < 0.001). Additionally, there was a notable increase in fat-free mass (FFM) (WMD = 0.20 kg; 95% CI, 0.06-0.34; p = 0.005). However, no significant impact of chitosan on body mass index (BMI) (WMD = -0.35 kg/m2, 95% CI: -0.71, 0.00; p = 0.054) and waist circumference (WC) (WMD = -0.71 cm, 95% CI: -1.49, 0.05; p = 0.069) was observed. Overall, chitosan supplementation shows promise in improving obesity indicators by reducing BFP and increasing FFM. However, further well-designed studies with larger sample sizes are needed to confirm these findings.

Recent developments in the biomedical and anticancer applications of chitosan derivatives

Chitosan is a natural polymer derived from chitin. It has significant applications in various fields due to its unique physicochemical properties, biocompatibility, and biodegradability. These important properties of chitosan make it an attractive candidate for various anti-cancer activities and biomedical applications, including tissue engineering. This review emphasizes the latest literature on anticancer applications of chitosan derivatives and in-depth study of biomedical applications. This review highlights the importance of biomedical applications and anti-cancer activities like breast, liver, colon, gastric, melanoma, colorectal, cervical, oral, and lymphoma cancer. Currently, there is a notable absence of recent reviews that comprehensively address these aspects such as Alejandro Elizalde-Cárdenas, et al. 2024, focuses only on Biomedical applications of Cs and its derivatives (Elizalde-Cárdenas et al., 2024). Jingxian Ding, et al. 2022 discussed the applications of Cs in some Cancer treatments (Mabrouk et al., 2024). However, our article aims to provide a comprehensive overview of the latest advancements in Cs derivatives in both fields. This manuscript is designed with proper diagrams, flow sheets and summarized tables to enhance the understanding of the reader. It also highlights recent advancements in the development of various chitosan derivatives, offering a comprehensive perspective for researchers and practitioners to further progress in biomedical and anticancer technologies.

Green fabrication of modified lignin/zeolite/chitosan-based composite membranes for preservation of perishable foods

Chitosan, as a kind of naturally occurring green and degradable material for the preservation of perishable foods, was investigated in this study with the objective of enhancing its preservation performances. Herein, lignin was modified using the solvent fractionation method (modified lignin, ML, including ML1-ML3), while natural clinoptilolite zeolite was modified using the alkali modification method (modified clinoptilolite zeolite, MCZ, including MCZ1-MCZ5). After optimizing the conditions, it was discovered that incorporating both ML3 and MCZ3 into pure chitosan-based membranes might be conducive to fabricate chitosan-based composite membranes for the preservation of perishable foods. As-prepared composite membranes possessed better visible light transmittance, antioxidant activity, and carbon dioxide/oxygen selectivity, resulting in improved preservation effects on the model perishable foods such as bananas, cherry tomatoes, and cheeses. These findings might indicate promising applications for chitosan-based composite membranes with modified lignin and zeolite in the field of eco-friendly degradable materials for the preservation of perishable foods.

Bio-inspired aFGF modification functionalized piezoelectric chitosan films for promoting scald wound healing

The application of acidic fibroblast growth factor (aFGF) has shown great potential in the treatment of scald or burn wounds with high morbidity and mortality, especially in promoting the repair of deep partial-thickness wounds. However, its short half-life and instability in vivo do pose challenges for clinical application. Herein, two kinds of bio-inspired modified piezoelectric chitosan (CS) films, namely heparin-coated CS film (HCS) and polydopamine-coated CS film (DCS), are facially fabricated and adopted as controlled-release platforms for local delivery of aFGF. Polydopamine or heparin layers serve as a bridge grafting on chitosan films, facilitating the loading of aFGF and enabling controlled release of aFGF from the piezoelectric film through intermolecular interactions. Additionally, these layers enhance the hydrophilicity and antibacterial properties of the bare CS film due to their inherent biological activities. Furthermore, the polydopamine coating imparts photothermal activity to the CS film. The in vivo experiments ascertain that the synergetic effect of the controlled-released aFGF and low temperature photothermal therapy collectively accelerate scald wound healing outcomes within 14 days by facilitating granulation formation, collagen deposition, re-epithelialization and angiogenesis. This study opens up new possibilities for the development of multifunctional chitosan-based wound dressings and the creation of innovative drug delivery platforms.

A Review of Chitosan-Based Materials for Biomedical, Food, and Water Treatment Applications

Chitosan, a natural biopolymer with excellent biocompatibility, biodegradability, and modifiable structure, has broad applications in regenerative medicine, tissue engineering, food packaging, and environmental technology. Its abundance, solubility in acidic solutions, and capacity for chemical modification make it highly adaptable for creating specialized derivatives with enhanced properties. Recent advances have demonstrated chitosan's efficacy in composite systems for tissue regeneration, drug delivery, and antimicrobial applications. This review examines chitosan's unique properties, with a focus on its antibacterial activity as influenced by factors like pH, concentration, molecular weight, and deacetylation degree. Additionally, chitosan's potential as a sustainable, non-toxic material for eco-friendly packaging and water treatment is explored, highlighting the growing interest in chitosan composites with other polymers and metallic nanoparticles for enhanced biomedical and environmental applications.

Thermosensitive hydrogel doped with osteoconductive fillers for the treatment of periodontitis periapicalis chronica: from synthesis to clinical trial

Herein, a chitosan-based thermosensitive hydrogel (CH) containing hydroxyapatite (HAp), poly(lactic acid) (PLDLLA) or their mixture is proposed as an innovative, biomimetic composition with antimicrobial and bone-forming properties for guided bone regeneration. The modified hydrogels were synthesized and characterized to verify their suitability for the treatment of periodontitis periapicalis chronica. Compared to the unmodified hydrogel, both CH_HAp and CH_PLDLLA revealed improved mechanical properties, as evidenced by rotational rheology. FTIR analysis proved that no chemical interplay existed between the components. All the tested samples displayed no cytotoxicity against osteoblast-like cell culture and confirmed antimicrobial features, both crucial from an application perspective. Radiation sterilization dosage was tailored for the tested samples to maintain sterility for a minimum of 8 weeks of storage and limit crosslinking of the samples. Finally, the hydrogel was used in a clinical trial to treat a patient with chronic inflammation of periapical tissues in teeth 26 and 27. The medical procedure proved the safety, nontoxicity, non-allergenicity, and, most importantly, bone-forming properties of the hydrogel formulation. The kinetics of new bone formation was analyzed in-depth using graphical cross-sections of anatomical structures obtained from pre- and post-operative CBCT scans.

Cotton-like antibacterial polyacrylonitrile nanofiber-reinforced chitosan scaffold: Physicochemical, mechanical, antibacterial, and MC3T3-E1 cell viability study

Bio-scaffolds, while mimicking the morphology of native tissue and demonstrating suitable mechanical strength, enhanced cell adhesion, proliferation, infiltration, and differentiation, are often prone to failure due to microbial infections. As a result, tissue engineers are seeking ideal scaffolds with antibacterial properties. In this study, silver nanoparticles (AgNPs) were integrated into cotton-like polyacrylonitrile nanofibers via a polydopamine (PDA) interlayer (Ag@p-PAN). These Ag@p-PAN nanofibers were then incorporated into the chitosan (CS) matrix, developing an antibacterial CS/Ag@p-PAN composite scaffold. The composite scaffold features an interconnected porous morphology with fiber-infused pore walls, improved water absorption and swelling properties, a controlled degradation profile, enhanced porosity, better mechanical strength, strong antibacterial properties, and excellent MC3T3-E1 cell viability, adhesion, proliferation, and infiltration. This study presents a novel method for reinforcing CS-based scaffolds by incorporating bioactive nanofibers, offering potential applications in tissue engineering and other biomedical fields.

Rational design of antibiotic-free antimicrobial contact lenses: Trade-offs between antimicrobial performance and biocompatibility

Microbial keratitis associated with contact lenses (CLs) wear remains a significant clinical concern. Antibiotic therapy is the current standard of care. However, the emergence of multidrug-resistant pathogens necessitates the investigation of alternative strategies. Antibiotic-free antimicrobial contact lenses (AFAMCLs) represent a promising approach in this regard. The effectiveness of CLs constructed with a variety of antibiotic-free antimicrobial strategies against microorganisms has been demonstrated. However, the impact of these antimicrobial strategies on CLs biocompatibility remains unclear. In the design and development of AFAMCLs, striking a balance between robust antimicrobial performance and optimal biocompatibility, including safety and wearing comfort, is a key issue. This review provides a comprehensive overview of recent advancements in AFAMCLs technology. The focus is on the antimicrobial efficacy and safety of various strategies employed in AFAMCLs construction. Furthermore, this review investigates the potential impact of these strategies on CLs parameters related to wearer comfort. This review aims to contribute to the continuous improvement of AFAMCLs and provide a reference for the trade-off between resistance to microorganisms and wearing comfort. In addition, it is hoped that this review can also provide a reference for the antimicrobial design of other medical devices.