Micro/Nanorobotic Swarms: From Fundamentals to Functionalities

Abstract

Swarms, which stem from collective behaviors among individual elements, are commonly seen in nature. Since two decades ago, scientists have been attempting to understand the principles of natural swarms and leverage them for creating artificial swarms. To date, the underlying physics; techniques for actuation, navigation, and control; fieldgeneration systems; and a research community are now in place. This Review reviews the fundamental principles and applications of micro/ nanorobotic swarms. The generation mechanisms of the emergent collective behaviors among the micro/nanoagents identified over the past two decades are elucidated. The advantages and drawbacks of different techniques, existing control systems, major challenges, and potential prospects of micro/nanorobotic swarms are discussed.

Open Questions of Chemically Powered Nano- and Micromotors

“…In the lab or our bodies, a micromotor is often surrounded by either its peers or foreigners in the environment, such as cells, microorganisms, debris, etc. The inevitable interaction of a micromotor with its neighbors , could give rise to a rich variety of collective behaviors including schooling, swarming, dynamic clustering, and even predator–prey interactions (see refs − and references therein). Understanding how these interactions arise is therefore important for fundamental and applied reasons.…”

Colloidal Self‐Assembly: From Passive to Active Systems

“…Electric fields represent another popular method to power the propulsion of colloids and regulate their dynamic assemblies, where the colloids are driven either by AC electric fields via induced charge electrophoresis (ICEP) mechanisms, [72] or by high strength DC electric fields as Quincke roller that can run and tumble freely on a flat plate due to the torque generated by a uniform DC electric field applied perpendicular to the plate in conducting fluids [73] . As the crowded suspension of colloidal particles interacts with each other through dipole‐dipole and hydrodynamic interactions, intricate dynamic structures and assembled clusters may be formed [74] . By altering parameters like the field strength, frequency, and direction of the electric field, a high degree of control over the assembly process and the resulting structures can be achieved.…”

“…[73] As the crowded suspension of colloidal particles interacts with each other through dipole-dipole and hydrodynamic interactions, intricate dynamic structures and assembled clusters may be formed. [74] By altering parameters like the field strength, frequency, and direction of the electric field, a high degree of control over the assembly process and the resulting structures can be achieved.…”

Magnetic Microrobot Swarms with Polymeric Hands Catching Bacteria and Microplastics in Water

“…Micro/nanorobots are artificial machines characterized by motion abilities, usually powered by nearby chemicals (e.g., H 2 O 2 , enzymes), external energy fields (light, magnetic, acoustic, and electric), or inherent self-propulsion mechanisms. − Endowed by programmable functionalities or collective behaviors, micro/nanorobots strongly improve the performance of nonmotile systems. − Among them, magnetically driven micro/nanorobots with swarming behavior hold immense promise for achieving more intricate functionalities. Microrobot swarms can be likened to singular robotic entities working collaboratively, emulating the collective behaviors observed in natural swarms. − Microrobot collectives’ synchronized and controlled actions can further amplify functional efficiency as compared to individual units’ capacities and enable them to collaborate and generate higher-order functionalities. ,− …”

“… 35 − 39 Microrobot collectives’ synchronized and controlled actions can further amplify functional efficiency as compared to individual units’ capacities and enable them to collaborate and generate higher-order functionalities. 37 , 40 − 46 …”