Metal-based nanomaterials usually have broad-spectrum antibacterial properties, low biological toxicity and no drug resistance due to their intrinsic enzyme-like catalytic properties and external field (magnetic, thermal, acoustic, optical and electrical) responsiveness. Herein, iron oxide (Fe3O4) nanoparticles (IONPs) synthesized by us have good biosafety, excellent photothermal conversion ability and peroxidase-like catalytic activity, which can be used to construct a photothermal-enzymes combined antibacterial treatment platform. IONPs with peroxide-like catalytic activity can induce H2O2 to catalyze the production of •OH in a slightly acidic environment, thus achieving certain bactericidal effects and increasing the sensitivity of bacteria to heat. When stimulated by near-infrared light, the photothermal effect could destroy bacterial cell membranes, resulting in cleavage and inactivation of bacterial protein, DNA or RNA. Meanwhile, it can also improve the catalytic activity of peroxidase-like and promote IONPs to catalyze the production of more •OH for killing bacteria. After IONPs synergistic treatment, the antibacterial rate of Escherichia coli and Staphylococcus aureus reached nearly 100%. It also has an obvious killing effect on bacteria in infected wounds of mice and can effectively promote the healing of S. aureus-infected wounds, which has great application potential in clinical anti-infection treatment.
Because of their remarkable qualities including changeable chemical composition, good redox characteristics, and ease of manufacture, non-enzymatic glucose sensors based on metallic hydroxides have attracted much interest. However, enhancement of their peroxidase-like catalytic activity is challenging due to their poor substrate affinity and low electrical conductivity, affecting electron transfer. Herein, a three-dimensional hierarchical architecture of Ni/Co-decorated-Fe layered double hydroxide (NiCoFe-LDH) was straightforwardly constructed on Fe foam (FF) via a feasible corrosion strategy, and the non-enzymatic glucose sensing properties of the NiCoFe-LDH/FF electrode were investigated. In the linear detection range of 0.010–0.1 mM, the electrode exhibits an extreme sensitivity of 5717 μA mM−1 cm−2 with a low threshold for glucose determination of 2.61 μM (S/N = 3) and a short reaction time (∼2 s), which is ascribed to its specific intertwined nanosheet-like morphology with rich electron transfer passages that enhance conductivity and improve the accessibility to more active catalytic sites for glucose oxidation. Moreover, the electrode shows excellent selectivity, good stability, and promising practicality for glucose detection in actual serum samples. These results indicate that the feasible corrosion approach towards the simple synthesis of trimetallic layered double hydroxide electrodes results in improved affinity and stability, holding new prospects for achieving reliable, cost-efficient, and eco-friendly non-enzymatic glucose detection.
Bacterial infection has become a global health issue. The misuse of antibiotics has been resulting in increased drug resistance and bioaccumulation. Therefore, developing a highly safe antibacterial agent, with high antibacterial performance is demanding. Inspired by the natural motors performing automated tasks in complicated living environments, we demonstrate tadpole-like nanoparticles (TNPs) with several functions, including high photothermal conversion efficiency, peroxidase-like catalytic activity, glutathione peroxidase-like activity, and catalase-like activity. TNPs produce hydroxyl radical (•OH) at an extremely low concentration of hydrogen peroxide of 0.006%, which can damage bacterial cell membranes, proteins, and DNA. Moreover, the glutathione peroxidase-like activity disrupts the anti-oxidative mechanism of bacteria and improves the permeability of the cell membranes, consequently enhancing the killing effect of ROS. In addition, TNPs possess tadpole-like asymmetry to overcome Brownian motion, demonstrating strong directional motion propelled by O 2 . The in vivo experiments indicate that TNPs could also shorten the inflammatory period and promote angiogenesis, making them a very promising antibacterial agent.
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