Annan Liu,Jianwen Li,Wenrui Qu,Boyu Yang,Xingchen Li,Lei Li,Hao Liang,Andrew K. Whittaker,Kexin Wang,Ze Wang,Wenlai Guo,Quan Lin
Bacterial infection and excessive inflammation are key factors contributing to the difficulty of healing diabetic wounds. Therefore, the development of a wound dressing that effectively fights bacterial infections, and addresses the challenges of long-term inflammation and repair difficulties is essential in clinical practice. Herein, a multifunctional ZnAuNDs@hydrogel (ZAN@HG) nanocomposite wound dressing capable of releasing zinc ions, and enhanced fluorescent and photothermal performance was developed to promote methicillin-resistant Staphylococcus aureus (MRSA)-infected diabetic wounds healing. The nanocomposite hydrogel also indicates in real-time with dressing replacement is required. The synergistic mechanism of enhanced-photothermal therapy (PTT) and zinc supplementation of ZAN@HG nanocomposite, can efficiently accelerate wound healing. Its excellent antibacterial and anti-inflammatory properties, along with the ability to regulate cell migration, promote collagen deposition, and enhance angiogenesis, make it an ideal adjunct for diabetic wound treatment. Moreover, the fluorescent nanocomposite can serve as a “dashboard” for intelligent self-monitoring, indicating the residual level of therapeutic agents in the dressing. The variation in fluorescence intensity is visually discernible, providing medical staff with a clear visual cue of the need for dressing replacement, thus effectively mitigating secondary wound damage. This work provides a promising strategy for the treatment of clinical diabetic wounds, and the intelligent self-monitoring of residual drug in the dressing.
The highly effective detection of pathogens in complex biological samples is an attractive and critical topic of study. Bacitracin is a novel broad-spectrum antimicrobial peptide to enrich bacteria via interactions with the membrane surface of the different bacterial cells. In this study, for the first time, bacitracin was immobilized on the surface of Fe3O4@PDA magnetic nanoparticles for the enrichment of Staphylococcus aureus (G+) and Klebsiella pneumoniae (G−). Combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry, a rapid and sensitive detection method for these two bacteria was developed. In this method, the detectable concentration of bacteria was decreased by 2–3 orders of magnitude in unenriched samples. The enrichment and identification can be completed in one hour. All these results demonstrated that the bacitracin-functionalized magnetic composite has potential for use in the large-scale enrichment and isolation of target pathogens from complex biological samples, opening a new avenue for the rapid and sensitive detection of pathogens.
In this study, pullulan was oxidized by NaIO 4 into low, medium and high oxidation degrees (OPL1,OPL2,OPL3) and used as a crosslinker to enhance physicochemical and biological properties of the wound dressings based on polyvinyl alcohol(PVA)/chitosan/collagen (FPL,FOPL1,FOPL2,FOPL3). Physicochemical, mechanical and biological properties of OPL samples as well as crosslinked films were characterized. The results showed that OPL not only increased the cell viability of human skin fibroblasts but also promoted antibacterial activity. Fourier transform infrared spectroscopy, rheological and gel content results proved the crosslinking effect of OPL. Mechanical properties of FOPL2 and FOPL3 films was >2 times higher than FPL film. The viability of human skin fibroblast cells was higher than the control for all films, and antibacterial activity of the film FOPL3 was significantly higher compared to other films. Wound healing effect of FOPL3 film was evaluated in a methicillin-resistant staphylococcus aureus (MRSA) infected full-thickness skin defect model in mice. The results showed a significantly lower wound area after 7,10,14 days of treatment compared to the control group treated by normal saline. The findings of this research enlighten wound healing potentials of oxidized pullulan to be used as a multifunctional ingredient for the development of future skin care biomaterials.
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