Effective Antibacterial Activity of Degradable Copper-Doped Phosphate-Based Glass Nanozymes

Manganese dioxide nanozyme for reactive oxygen therapy of bacterial infection and wound healing

Reactive oxygen species (ROS) are the weapons of neutrophiles against bacterial pathogens, and also the central effectors in reactive oxygen therapy for skin and soft tissue infection. Nanozymes that spontaneously generate ROS under physiological conditions are new antibacterials that hold promise towards multidrug resistant pathogens. The clinical use of the nanozymes is however limited by their low biocompatibility and toxicity in vivo. Here, we develop an oleic acid (OA) nanoemulsion template method for the one-pot synthesis of OA-manganese dioxide (MnO₂) nanozyme. The OA-MnO₂ nanozyme showed high stability and biocompatibility under physiological conditions with marked oxidase-like activity. The ROS generated by the OA-MnO₂ nanozyme effectively kill the Gram-positive Staphylococcus aureus and the Gram-negative Escherichia coli strains. Moreover, the OA-MnO₂ nanozyme shows promising abilities to prevent and destruct biofilm formation by Staphylococcus aureus, and result in superior in vivo antibacterial performance as compared to vancomycin. The reactive oxygen therapy based on OA-MnO₂ nanozyme cures the infected skin and promotes wound healing in mice, manifesting its potential use in skin and soft tissue infection.

The Effects of Natural Products and Environmental Conditions on Antimicrobial Resistance

Due to the extensive application of antibiotics in medical and farming practices, the continued diversification and development of antimicrobial resistance (AMR) has attracted serious public concern. With the emergence of AMR and the failure to treat bacterial infections, it has led to an increased interest in searching for novel antibacterial substances such as natural antimicrobial substances, including microbial volatile compounds (MVCs), plant-derived compounds, and antimicrobial peptides. However, increasing observations have revealed that AMR is associated not only with the use of antibacterial substances but also with tolerance to heavy metals existing in nature and being used in agriculture practice. Additionally, bacteria respond to environmental stresses, e.g., nutrients, oxidative stress, envelope stress, by employing various adaptive strategies that contribute to the development of AMR and the survival of bacteria. Therefore, we need to elucidate thoroughly the factors and conditions affecting AMR to take comprehensive measures to control the development of AMR.