PEGylated curcumin-loaded poly(vinyl alcohol)/Zwitterionic poly(sulfobetaine vinylimidazole)-grafted chitosan nanofiber as a second-degree burn wound dressing

Evaluating the antibacterial and antibiofilm activities of chitosan derivatives containing six-membered heterocyclics against E. coli and S. aureus

Chitosan exhibits good biocompatibility and some antibacterial activity, making it a popular choice in biomedicine, personal care products, and food packaging. Despite its advantages, the limited antibacterial effectiveness of chitosan hinders its widespread use. Introducing a six-membered heterocyclic structure through chemical modification can significantly enhance its antimicrobial properties and broaden its potential applications. In order to explore the effect of six-membered heterocyclic structure on the antibacterial and antibiofilm activities of chitosan. In this study, seven chitosan derivatives containing six-membered heterocyclics were prepared. They were characterized using Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis. Cell viability assay showed that they were non-toxic. The antibacterial and antibiofilm activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were evaluated. Our research findings demonstrate that increasing the hydrophobicity, alkalinity and charge density of the substitute groups improved the antibacterial and antibiofilm activities of chitosan. This study also offers valuable insights into the quantitative structure-activity relationships of chitosan derivatives in terms of antibacterial and antibiofilm activities.

CDI crosslinked chitosan/poly (vinyl alcohol) electrospun nanofibers loaded with Achillea millefolium and Viola extract: A promising wound dressing

Biopolymer-based electrospun mats, mimicking the extracellular matrix, have been extensively explored in biomedical applications. This study compares Achillea millefolium (AM) and Viola (V) extracts for developing a biocompatible wound dressing. The extracts were incorporated into a Chitosan/polyvinyl alcohol (CS/PVA) matrix via electrospinning. Crosslinking with Carbonyldiimidazole (CDI) improved chemical stability, water resistance, and biodegradability. The resulting mats exhibited flawless interconnected nanofibers, confirming the presence of AM and Viola extracts as analyzed via FTIR. Significant differences were observed between these two herbal extracts, particularly in mechanical properties, with tensile strengths of 6.9 MPa for AM and 17.2 MPa for Viola. Viola extract demonstrated robust antibacterial properties, producing an 8.2 mm inhibition zone against Staphylococcus aureus, compared to AM's 30 %. The release of therapeutic agents indicated an initial rapid phase, followed by a controlled 72 h release at a consistent rate. Notably, Viola extract led to 80.9 % wound closure on the 10th day, surpassing AM extract at 63.7 %. In contrast, the control group achieved only 32.1 % closure. This comparative study underscores the distinct advantages of AM and Viola extracts in wound dressing applications. While AM presents specific strengths, Viola extract exhibits superior mechanical properties, antibacterial efficacy, and accelerated wound closure, suggesting its potential with significant clinical implications.

Nanosphere-reinforced polysaccharide self-healing hydrogels for infected wound healing

Bacterial infection remarkably impedes wound healing, with antibiotics traditionally serving as the primary therapeutic intervention. However, the escalating misuse of antibiotics and the emergence of bacterial resistance present substantial treatment challenges for infected wounds. Consequently, the development of antibiotic-free antimicrobial dressings holds pertinent research and clinical relevance. To this end, this study aimed to introduce an all-natural hydrogel dressing, amalgamating polyphenols and polysaccharides, exhibiting pronounced antibacterial and antioxidant properties without relying on antibiotics. First, we constructed curcumin-tannic acid‑zinc ion nanospheres (CTZN) through self-assembly. Our experimental results showed that the nanospheres had excellent biocompatibility, antioxidant, and antimicrobial abilities. Subsequently, we prepared carboxymethylated chitosan/oxidized sodium alginate hydrogels via Schiff base reactions. Incorporation of CTZN into the hydrogel system not only improves the inherent qualities of the hydrogel but also confers multifunctional properties, including antimicrobial, antioxidant, and anti-inflammatory abilities. In this study, we enhanced the physicochemical properties and biological activity of hydrogels by introducing natural material nanospheres, offering a novel approach that could pave the way for the development of purely natural biomaterial dressings.

Versatile Bioactive Glass/Zeolitic Imidazolate Framework-8-Based Skin Scaffolds toward High-Performance Wound Healing

Designing a novel biomaterial for wound healing is based on biocompatibility and excellent mechanical strength. In this study, bioactive glass (BG) and zeolitic imidazolate framework-8 (ZIF-8) have been incorporated into poly(ε-caprolactone)/poly(vinyl alcohol) (PCL/PVA) composite skin scaffolds via microfluidic electrospinning. Interestingly, the addition of ZIF-8 further strengthens the BG stability and demonstrates better antibacterial effects. Utilizing the slow release of Zn, Ca, and Si ions, it also significantly promotes growth factor expression and skin regeneration. In addition, it is further demonstrated by in vitro and in vivo studies that the prepared composite skin scaffolds possess excellent biocompatibility, antibacterial capabilities, and mechanical properties. The prepared BG/ZIF-8-loaded scaffold possesses high tensile strength (26 MPa) and excellent antibacterial properties (achieves 89.64 and 78.8% inhibition of E. coli and S. aureus, respectively), and cell viability increased by 51.2%. More importantly, the wound shrinkage of the BG/ZIF-8-loaded scaffold is better than that of an unloaded scaffold, and the shrinkage rates of PCL/PVA@BG/ZIF-8(1 wt %) group is 95% with 2.2 mm granulation growth thickness within 12 days. Thus, the composite skin scaffold loaded with BG/ZIF-8 prepared by microfluidic electrospinning provides a new perspective for accelerating wound healing and is a potential novel therapeutic strategy for efficient wound healing.