Microbot

Microbot, short for micro-robot, refers to a robot whose size is on the order of micrometers to millimeters, designed to operate in micro-scale environments such as microfluidic channels or within biological tissue. The term is commonly applied to devices capable of moving, sensing, or performing tasks under external control or autonomous operation. Microbots are distinguished from larger robots by their miniaturized actuation, sensing, and power systems, and in many designs by their use of external fields to enable propulsion.

Design and operation: Microbots often rely on microfabrication techniques or bottom-up assembly. Actuation methods include magnetic propulsion driven by external fields, electrostatic or electrothermal effects, piezoelectric propulsion, acoustic waves, and light-driven mechanisms. Some devices are powered wirelessly or harvest energy from the environment. Payloads may include drugs, contrast agents, or sensing reagents. Sensing capabilities can cover temperature, chemical composition, pH, or magnetic fields. Communication with controllers can use radio frequency, optical signals, magnetic induction, or passive backscatter.

Fabrication and materials: Common materials include silicon, polymers, ceramics, and magnetic alloys. Techniques encompass MEMS, LIGA, two-photon polymerization, electroplating, and micro-3D printing.

Applications: In medicine, microbots aim at targeted drug delivery, biopsy, or intracellular sensing, often with external guidance. In environmental monitoring, they can detect pollutants or perform micro-scale remediation. In research, they enable studies of transport at small scales and lab-on-a-chip systems.

Challenges and outlook: Key hurdles include precise control and navigation in viscous fluids, overcoming Brownian motion, manufacturing scalability, biocompatibility, and safety considerations. Ongoing research explores swarm approaches and hybrid propulsion to broaden capabilities while addressing regulatory and ethical aspects.