In Situ Fabrication of Silver Peroxide Hybrid Ultrathin Co-Based Metal-Organic Frameworks for Enhanced Chemodynamic Antibacterial Therapy.

Bacterial-induced infectious diseases have always caused an unavoidable problem and lead to an increasing threat to human health. Hence, there is an urgent need for effective antibacterial strategies to treat infectious diseases. Current methods are often ineffective and require large amounts of hydrogen peroxide (H2O2), with harmful effects on normal healthy tissue. Chemodynamic therapy (CDT) provides an ideal infection microenvironment (IME)-activated paradigm to tackle bacterial-related diseases. To take full advantage of the specificity of IME and enhanced CDT for wounds with bacterial infection, we have designed an intelligent antibacterial system that exploits nanocatalytic ZIF-67@Ag2O2 nanosheets. In this system, silver peroxide nanoparticles (Ag2O2 NPs) were grown on ultrathin zeolitic imidazolate framework-67 (ZIF-67) nanosheets by in situ oxidation, and then, ZIF-67@Ag2O2 nanosheets with the ability to self-generate H2O2 were triggered by the mildly acidic environment of IME. Lamellar ZIF-67 nanosheets were shown to rapidly degrade and release Co2+, allowing the conversion of less reactive H2O2 into the highly toxic reactive oxygen species hydroxyl radicals (•OH) for enhanced CDT antibacterial properties. In vivo results revealed that the ZIF-67@Ag2O2 nanosheet system exhibits excellent antibacterial performance against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The proposed hybrid strategy demonstrates a promising therapeutic strategy to enable antibacterial agents with IME-responsive nanocatalytic activity to circumvent antibiotic resistance against bacterial infections.

A multifunctional nanocatalytic system based on Chemodynamic-Starvation therapies with enhanced efficacy of cancer treatment.

A multi-functional nanocatalytic system based on combined therapies has attracted considerable research attention in recent years due to its potential in the treatment of cancer. Herein, ZnO2@Au@ZIF-67 nanoparticles (NPs) based on hydroxyl radical (•OH) mediated chemodynamic therapy (CDT) and glucose-exhausting starvation therapy (ST) were constructed. Specifically, in the acidic tumor microenvironment (TME), the pH responsive decomposition of the shell ZIF-67 triggered the release of the Fenton-like catalyst Co2+, after which the exposed zinc peroxide (ZnO2) reacted with H2O (H+) to generate O2 and hydrogen peroxide (H2O2). The generated O2 could alleviate hypoxia in the TEM and interact with ultra-small Au NPs originally coated on ZnO2 to catalyze intracellular glucose and to produce another source of H2O2. While the glucose consumption caused the starvation of tumor cells, the generated H2O2 from dual sources reacted with the catalyst Co2+ to generate highly toxic •OH for CDT. Systematic in vitro and in vivo experiments were carried out to evaluate this nanocatalytic system, and the results showed an enhanced efficacy of this cancer therapy.