Bienzymatic synergism of vanadium oxide nanodots to efficiently eradicate drug-resistant bacteria during wound healing in vivo.

Antibiotic resistance is a common phenomenon observed during treatment with antibacterials. Use of nanozymes, especially those with synergistic enzyme-like activities, as antibacterials could overcome this problem, but their synthesis is limited by their high cost and/or complex production process. Herein, vanadium oxide nanodots (VOxNDs) were prepared via a one-step bottom-up ethanol-thermal method using vanadium trichloride as the precursor. VOxNDs alone possess bienzyme mimics of peroxidase and oxidase. Accordingly, highly efficient antibacterials against drug-resistant bacteria can be obtained through synergistic catalysis; the oxidase-like activity decomposes O2 to generate superoxide anion radical (O2-) and hydroxyl radicals (OH), and the intrinsic peroxidase-like activity can further induce the production of OH from external H2O2. Consequently, H2O2 concentration could decrease up to four magnitude orders with VOxNDs to achieve an antibacterial efficacy similar to that of H2O2 alone. Wound healing in vivo further confirms the high antibacterial efficiency, good biocompatibility, and application potential of the synergistic antibacterial system due to the "nano" structure of VOxNDs. The method of synthesis of nanodot antibacterials described in this paper is inexpensive, and the results of this study reveal the multi-enzymatic synergism of nanozymes.

Ma W ，Zhang T ，Li R ，Niu Y ，Yang X ，Liu J ，Xu Y ，Li CM ... -  《-》

Bactericidal effects and accelerated wound healing using Tb(4)O(7) nanoparticles with intrinsic oxidase-like activity.

Li C ，Sun Y ，Li X ，Fan S ，Liu Y ，Jiang X ，Boudreau MD ，Pan Y ，Tian X ，Yin JJ ... -  《JOURNAL OF NANOBIOTECHNOLOGY》

Controlled-temperature photothermal and oxidative bacteria killing and acceleration of wound healing by polydopamine-assisted Au-hydroxyapatite nanorods.

Since skin wounds are subject to bacterial infection and tissue regeneration may be impeded, there is demand for biomaterials that possess rapid bactericidal and tissue repair capability. Herein we report in situ promotion of wound healing by a photothermal therapy (PTT) assisted nanocatalytic antibacterial system utilizing a polydopamine (PDA) coating on hydroxyapatite (HAp) incorporated with gold nanoparticles (Au-HAp). The PDA@Au-HAp NPs produce hydroxyl radicals (OH) via catalysis of a small concentration of H2O2 to render bacteria more vulnerable to the temperature change. The antibacterial efficacy against Escherichia coli and Staphylococcus aureus is 96.8% and 95.2%, respectively, at a controlled photo-induced temperature of 45 °C that causes no damage to normal tissues. By combining catalysis with near-infrared (NIR) photothermal therapy, the PDA@Au-HAp NPs provide safe, rapid, and effective antibacterial activity compared to OH or PTT alone. In addition, this system stimulates the tissue repairing-related gene expression to facilitate the formation of granulation tissues and collagen synthesis and thus accelerate wound healing. After the 10-day treatment of skin wounds in vivo, PDA@Au-HAp group exhibits quicker recovery than the control group and both sterilization and healing are completed after the 10-day treatment. This study presents in situ promotion of wound healing by a low-temperature photothermal therapy (PTT) assisted nanocatalytic antibacterial system utilizing a polydopamine (PDA) coating on hydroxyapatite (HAp) incorporated with gold nanoparticles (Au-HAp). The PDA@Au-HAp NPs produce hydroxyl radicals (OH) via catalysis of a small concentration of H2O2 to render bacteria more vulnerable to temperature change. After irradiation by 808 nm laser, the antibacterial efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) is 96.8% and 95.2%, respectively, at a low photo-induced temperature of 45 °C which causes no damage to normal tissues. In addition, this system stimulates the tissue repairing-related gene expression to facilitate the formation of granulation tissues and collagen synthesis and accelerate wound healing.

Xu X ，Liu X ，Tan L ，Cui Z ，Yang X ，Zhu S ，Li Z ，Yuan X ，Zheng Y ，Yeung KWK ，Chu PK ，Wu S ... -  《-》

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 ... -  《-》

Photosensitive properties, synergistic antibacterial abilities of intelligent response-type self-assembled nanoparticle TiO(2)@V(2)O(5).

Liu Y ，Liu J ，Guo X ，Lin A ，Wen Y ，Chen X ，Zhu X ，Liu J ，Luo Z ... -  《-》