Micro- and Nanomotors: Engineered Tools for Targeted and Efficient Biomedicine

Over the past two decades, nanotechnology has made significant progress toward the development and applications of micromotors (MMs) and nanomotors (NMs). Characterized by their capability to self-propel and swim in fluids, they have emerged as promising tools in various fields, particularly in biomedicine. This Review presents an overview of the current state of MMs and NMs, their motion in viscous media and complex environments, their interaction with biological barriers, and potential therapeutical applications. We identify the choice of appropriate administration routes to reach their target location as a key aspect of the success of MMs and NMs in biomedical applications. Looking ahead, we envision NMs playing a key role in treating diverse medical disorders, as recent proof-of-concept in vivo studies demonstrate their distinct capabilities and versatility. However, addressing regulatory, scalability, biocompatibility, and safety concerns remains imperative for the successful translation of NMs into clinical trials and industrial-scale production. This work provides a guideline for researchers, guiding them through the current landscape, challenges, and prospects of using MMs and NMs in biomedicine, thereby encouraging their responsible development and positioning in the future of nanomedicine. Furthermore, we outline critical areas for further research, including studies on biocompatibility, safety, and methods to overcome physical obstacles.