Structure and Mechanisms of Micro-Nano Scale Microrobots

Micro-robots refer to mechanical devices designed to operate at the micro-scale, with dimensions smaller than one millimetre. Traditional MEMS-based designs encounter bottlenecks when scaled down to the micro- and nanoscale, experiencing power reduction alongside diminished reliability and lifespan. Advances in bioengineering and nanotechnology have overcome this impasse, giving rise to three core propulsion methods: chemically driven, externally physically field-driven, and bio-hybrid driven. These approaches lay the foundation for further micro-robot development, enabling micro and nanoscale devices to transition from conceptualisation to practical application.This paper focuses on the structure and mechanisms of micro-nano robots. By analysing structural types and outlining core design principles, it details the motion and control methods for various classes of microrobots through case studies. It explores practical applications to highlight potential and structural constraints, emphasising challenges such as biocompatibility, precise navigation control, and scalable production. This review aims to provide practitioners with a broad perspective and increase awareness within the field.