External Power-Driven Microrobotic Swarm: From Fundamental Understanding to Imaging-Guided Delivery

Abstract

Untethered micro/nanorobots have been widely investigated owing to their potential in performing various tasks in different environments. The significant progress in this emerging interdisciplinary field has benefited from the distinctive features of those tiny active agents, such as wireless actuation, navigation under feedback control, and targeted delivery of small-scale objects. In recent studies, collective behaviors of these tiny machines have received tremendous attention because swarming agents can enhance the delivery capability and adaptability in complex environments and the contrast of medical imaging, thus benefiting the imaging-guided navigation and delivery. In this review, we summarize the recent research efforts on investigating collective behaviors of external power-driven micro/nanorobots, including the fundamental understanding of swarm formation, navigation, and pattern transformation. The fundamental understanding of swarming tiny machines provides the foundation for targeted delivery. We also summarize the swarm localization using different imaging techniques, including the imaging-guided delivery in biological environments. By highlighting the critical steps from understanding the fundamental interactions during swarm control to swarm localization and imaging-guided delivery applications, we envision that the microrobotic swarm provides a promising tool for delivering agents in an active, controlled manner.

Cooperative transport by flocking phototactic micromotors

“…Inspired by the ant army carrying food cooperatively, the driving force would be much enhanced by socializing the motors. [28][29][30][31][32] Therefore, growing endeavors have been made to construct intelligent micro/nanorobot swarms to cooperatively transport large cargoes. 33 The key to achieving cooperative transport is to align the forces of active individuals in the swarms in the same direction.…”

Tethered and Untethered 3D Microactuators Fabricated by Two-Photon Polymerization: A Review

“…In order to adapt to more complex environments for practical application, microactuators that are responsive to dual stimuli and able to be controlled by multiple external powers were developed [44,189]. Correspondingly, this compound driving method can be named as multi-field-coupling manipulation.…”

“…Considering the above advantages, 3D laser printing is considered as a very promising technology for the manufacturing of 3D microactuators, and a large amount of interesting work has been done [41]. Although many inspiring reviews about 3D microrobotics have been made by researchers [42][43][44][45][46][47][48][49], few articles focused on 3D microactuators made with 3D laser printing based on TPP. The employment of 3D laser printing for 3D microactuators not only provides a flexible and powerful tool to fabricate new stimulus-responsive devices, but also paves a new path for the design of the operation mechanisms of 3D microactuators.…”

A Review of Microrobot’s System: Towards System Integration for Autonomous Actuation In Vivo

“…Thirdly, hybrid actuation can carry out long-distance and fine actuation to achieve whole-body work [ 1 ]. Lastly, actuation and control of microrobot populations are urgently needed to conquer the limitations of the single microrobot in the body [ 126 ].…”