A convoy of magnetic millirobots transports endoscopic instruments for minimally-invasive surgery

TL;DR

This paper introduces a team of magnetically controlled millirobots that collaboratively transport medical instruments through biological lumens, demonstrating enhanced force and capabilities for minimally-invasive surgery.

Contribution

It presents the first convoy of millirobots with optimized feet and wireless control to carry heavy loads and perform electrocauterization in biological environments.

Findings

Convoy of millirobots doubles actuating force compared to single units.

Optimized feet increase propulsive force threefold on slippery surfaces.

Successful electrocauterization in biological lumens demonstrates practical surgical application.

Abstract

Small-scale robots offer significant potential in minimally-invasive medical procedures. Due to the nature of soft biological tissues, however, robots are exposed to complex environments with various challenges in locomotion, which is essential to overcome for useful medical tasks. A single mini-robot often provides insufficient force on slippery biological surfaces to carry medical instruments, such as a fluid catheter or an electrical wire. Here, for the first time, we report a team of millirobots (TrainBot) that can generate around two times higher actuating force than a TrainBot unit by forming a convoy to collaboratively carry long and heavy cargos. The feet of each unit are optimized to increase the propulsive force around three times so that it can effectively crawl on slippery biological surfaces. A human-scale permanent magnetic set-up is developed to wirelessly actuate and control the TrainBot to transport heavy and lengthy loads through narrow biological lumens, such as the intestine and the bile duct. We demonstrate the first electrocauterization performed by the TrainBot to relieve a biliary obstruction and open a tunnel for fluid drainage and drug delivery. The developed technology sheds light on the collaborative strategy of small-scale robots for future minimally-invasive surgical procedures.