Micro/nanomotors in targeted drug delivery: Advances, challenges, and future directions

The therapeutic efficacy of drugs is highly dependent on their successful delivery to the target site. However, achieving targeted drug delivery to diseased areas remains a significant challenge. Current drug delivery systems based on nanocarriers often suffer from inefficiencies due to their lack of intrinsic propulsion and active targeting capabilities. Micro/nanomotors (MNMs), which are miniature machines capable of converting chemical or external energy into mechanical energy, offer a promising solution. Unlike traditional nanoparticles (NPs) that rely on passive diffusion through blood circulation, MNMs exhibit active locomotion, providing a significant advantage in future drug delivery applications. This review primarily focuses on the progress in research of MNMs in the realm of drug delivery. We present a succinct overview of MNMs and subsequently classify them based on their modes of mobility. Then we comprehensively summarize the applications of micro/nanomotor-based drug delivery systems in the treatment of various diseases, including cancer, bacterial infections, cardiovascular diseases, and others. Based on the current research status, we summarize the potential challenges, possible solutions, and prospect several key directions for future studies in active-targeted drug delivery using MNMs. Future research should focus on improving motor delivery efficiency, biosafety measures, productivity, and maneuverability.