Stimuli-triggered pollen-inspired micro/nanorobots for advanced therapeutics

Stimuli-responsive micro/nanorobots have revolutionized biomedical research by overcoming the therapeutic limitations that require critical medical interventions. These micro/nanorobots are designed to move through the body's circulatory system and hold promise for advanced micro/nano surgery, targeted drug delivery, immunotherapy, and combating bacterial infections. The efficacy of these bots largely relies on specific physicochemical attributes (such as high biocompatibility, in vivo site-specific adhesion properties, high surface area at the nanoscale, ability to combat immune rejection and controlled actuation). Biomimetic pollen-like micro/nanorobots (P-M/N-bots), inspired by pollen, have emerged as suitable structures for in vivo applications. These structures are meticulously fabricated through the chemical modification of materials such as silica and zinc oxide. After fabrication, the micro/nanorobots′ movement can be precisely controlled by different stimuli (such as near-infrared radiation (NIR), magnetic fields, and temperature variations, among others). Despite the growing scientific outcomes, we are yet to conduct a concise review of the development and progress of on-the-rise P-M/N-bots. Therefore, it is necessary to provide an overview of the current developments in intelligent P-M/N-bots to encourage future developments in this field. Hence, in this review, we discuss the synthesis methods for P-M/N-bots and feasible actuation methods, including NIR, magnetic field, pH, and temperature. We emphasize the various therapeutic applications of the P-M/N-bots in biomedical applications, focusing on anti-cancer therapies, targeted drug delivery, anti-bacterial effects, and curing inflammatory conditions. Furthermore, we discuss potential challenges in the clinical application of P-M/N-bots. Anticipating the future of this field, we believe that this review will serve as a valuable guide for the development of promising P-M/N-bots with enhanced therapeutic outcomes.