Micro/nanomotors from single modal to multimodal propulsion

The realm of micro/nanomotors (MNMs) is continuously witnessing significant advancements, with multimodal propulsion emerging as a potential strategy to address the limitations of single-mode propulsion systems, such as low propulsion efficiency and limited versatility. The multimodal propulsion MNMs hold great promise in addressing challenges of MNM performing tasks in complex environments, offering enhanced adaptability and performance. We comprehensively review the core mechanisms of multimodal propulsion, driven by the combination of chemical, physical, and biological stimuli, and their synergistic effects in driving the movement of these MNMs. Furthermore, we delve into material design innovations in multimodal MNMs, highlighting the importance of metal-based materials, semiconductor-based materials, and polymer-based materials in enhancing their performance and responsiveness. In terms of fabrication techniques, we examine the role of template-assisted synthesis, layer-by-layer assembly, and self-assembly methods in creating complex and precise MNM structures. We specify emerging applications of multimodal MNMs, highlighting their efficacy in precise diagnosis and therapy, environmental remediation, as well as micromanipulation and assembly. Future research directions and perspectives, emphasizing the need for continuous innovation to fully harness the capabilities of these MNMs, are also elaborated. This review aims to provide a comprehensive understanding of the propulsion mechanisms, fabrication techniques, and applications of the multimodal MNMs, thereby serving as a springboard for further advancements in the field of MNMs.