A novel antibacterial agent based on AgNPs and Fe(3)O(4) loaded chitin microspheres with peroxidase-like activity for synergistic antibacterial activity and wound-healing.

In this study, a novel antibacterial agent was developed based on chitin nanofibrous microspheres loaded with AgNPs and Fe3O4 nanoparticles (Ag-Fe3O4-NMs) for synergistic antibacterial activity and wound healing. Ag-Fe3O4-NMs was prepared via an in situ synthetic method which showed an excellent porosity and wettability. Moreover, Ag-Fe3O4-NMs were capable of sustained release of Ag+ and catalysed the decomposition of low H2O2 concentrations to generate hydroxyl radical (OH). The OH and Ag+ showed higher antibacterial activity and inhibited the toxicity with high dose of AgNPs and H2O2. In vitro biocompatibility results suggested that Ag-Fe3O4-NMs have low toxicity and low hemolysis. Thus, a novel antibacterial agent with enhanced synergistic antibacterial activity was obtained by combination of Ag-Fe3O4-NMs and H2O2 at a low and biologlically safe dosage, which could facilitate fibroblast growth, accelerate epithelialization, and promote the healing rate of infected wounds.

Yu N ，Cai T ，Sun Y ，Jiang C ，Xiong H ，Li Y ，Peng H ... -  《-》

A novel antibacterial acellular porcine dermal matrix cross-linked with oxidized chitosan oligosaccharide and modified by in situ synthesis of silver nanoparticles for wound healing applications.

Not only are the physicochemical properties and biocompatibility of biomaterials important considerations, but also their antibacterial properties. In this study, a novel chemically-cross-linked antibacterial porcine acellular dermal matrix (pADM) scaffold was fabricated according to a two-step method. A naturally-derived oxidized chitosan oligosaccharide (OCOS) was used to cross-linked pADM (termed OCOS-pADM) to improve its physicochemical properties. Residual aldehyde groups within the OCOS-pADM were used in a redox reaction with Ag ions to produce Ag nanoparticles (AgNPs) in situ. As the AgNPs were tightly adhered onto the scaffold fibrils (termed OCOS-AgNPs-pADM), this effectively functionalized scaffold with antibacterial properties. The generated AgNPs were characterized by UV-Vis diffuse reflectance spectroscopy, XPS and SEM. The results of DSC, TG and enzymatic degradation demonstrated that OCOS-AgNPs-pADM possessed improved thermal stability and resistance to enzymatic degradation compared with pADM scaffolds. The kinetic experiment of the release of silver showed that silver was released in a controllable way. After introducing AgNPs into scaffolds, the OCOS-AgNPs-pADM possessed wide-spectrum antibacterial activity against Escherichia coli and Staphylococcus aureus. Furthermore, MTT assay and CLSM showed that the scaffolds had good biocompatibility. Pieces of OCOS-AgNPs-pADM were implanted into Sprague-Dawley rats to characterize their ability to repair full-thickness skin wounds. And results showed that the OCOS-AgNPs-pADM could accelerate the wound healing process. Overall, this work contributes new insight into the chemical cross-linking and functionalization of pADM scaffolds. In addition, as novel antibacterial scaffolds, OCOS-AgNPs-pADMs have the potential for development as wound dressing materials.

Chen Y ，Dan N ，Dan W ，Liu X ，Cong L ... -  《-》

Synthesis of silver/Fe(3)O(4)@chitosan@polyvinyl alcohol magnetic nanoparticles as an antibacterial agent for accelerating wound healing.

Bacterial infection causes wound inflammation and slows wound healing, posing a great threat to human health, which needs to explore more antibacterial nanobiomaterials to promote wound healing. Therefore, this study was conducted to develop low-cost silver/Fe3O4@Chitosan@polyvinyl alcohol (Ag/Fe3O4@CS@PVA) via a one-pot method to promote healing in bacteria-infected wounds. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM) confirmed that Ag/Fe3O4@CS@PVA was successfully prepared. In vitro antibacterial experiments demonstrated strong antibacterial activity of Ag/Fe3O4@CS@PVA against Escherichia coli and Staphylococcus aureus. The Ag/Fe3O4@CS@PVA destroyed the bacterial cell membrane or internal structure, thus resulting in cell death for antibacterial effects. Cytotoxicity and hemolysis rate tests showed that Ag/Fe3O4@CS@PVA posed fine biocompatibility. In addition, in vivo assays confirmed that Ag/Fe3O4@CS@PVA not only promoted the healing of wound infection caused by bacteria, but also had no toxic effect on mouse organs. Therefore, the low-cost Ag/Fe3O4@CS@PVA nanocomposites have great potential in controlling 'bacterial' pathogen.

Qi J ，Zhang J ，Jia H ，Guo X ，Yue Y ，Yuan Y ，Yue T ... -  《-》

Synergistic and On-Demand Release of Ag-AMPs Loaded on Porous Silicon Nanocarriers for Antibacteria and Wound Healing.

Jin Y ，Yang Y ，Duan W ，Qu X ，Wu J ... -  《-》

Nano-silver-decorated microfibrous eggshell membrane: processing, cytotoxicity assessment and optimization, antibacterial activity and wound healing.

Liu M ，Luo G ，Wang Y ，Xu R ，Wang Y ，He W ，Tan J ，Xing M ，Wu J ... -  《Scientific Reports》