Responsive metal-organic framework nanocarrier delivery system: An effective solution against bacterial infection

Bacterial infection is a serious threat to human health and is one of the main causes of death worldwide. The discovery of antibiotics is considered a great milestone in the history of medicine; however, the excessive utilization of antibiotics engenders the emergence of multi-drug-resistant microorganisms, commonly referred to as 'superbugs'. Nano delivery systems have the potential to enhance therapeutic effectiveness and mitigate adverse effects in antimicrobial applications by facilitating targeted drug release at the specific site of bacterial infection. Metal-organic frameworks (MOFs), being a novel porous material, have gained significant attention in the field of biomedical applications, particularly in the development of drug delivery systems (DDSs), owing to their distinctive attributes encompassing facile functionalization, exceptional biocompatibility, biodegradability, crystallinity, porosity, and large internal surface area. However, the drug-release mechanisms of MOF-based, stimulus-responsive DDSs for the treatment of bacterial infections have rarely been comprehensively summarized. Here, we have discussed various antibacterial drug-release mechanisms based on specific stimuli, endogenous (such as pH, ROS, enzymatic, etc.), exogenous (such as light, temperature, ultrasound, or magnetic field), or multiple stimuli (light and pH, light and temperature, etc.). This review provides a comprehensive overview of the correlation between the characteristics and attributes of MOFs, and it also discusses the challenges and future directions of MOF-based, stimulus-responsive DDSs. It will provide us with a better under-standing of how to design more efficient MOF-based DDSs for the treatment of bacterial infections.