A Convoy of Magnetic Millirobots Transports Endoscopic Instruments for Minimally-Invasive Surgery.

2024-07-01

Advancement of science

AI Summary

In minimally invasive surgery, microrobots suffer from insufficient traction on slippery, soft-tissue surfaces, hindering reliable transport of elongated instruments (e.g., endoscopes, catheters). To address this, we present TrainBot—a magnetically actuated millirobotic convoy system—where multiple millirobots cooperatively form a “train-like” configuration to enable stable, heavy-load instrument transport within narrow anatomical lumens (e.g., bile ducts, intestines). Key contributions include: (i) the first demonstration of millirobotic swarm-based cargo transport, achieving a twofold increase in output force; (ii) bioinspired, biocompatible microstructured feet that enhance individual propulsion force by threefold; and (iii) the world’s first millirobot-assisted electrodilatation procedure for biliary stricture relief. Integrated with wireless permanent-magnet actuation and multi-robot closed-loop control, TrainBot successfully validated biliary obstruction clearance, drainage tunnel creation, and targeted drug delivery in human-scale organ phantoms—significantly advancing precision instrument delivery in minimally invasive interventions.

Technology Category

• Intelligent Robots: Multi-Robot Systems
• Multiagent Systems: Teamwork
• Machine Learning: Adversarial Learning & Robustness

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• Web Mining and Content Analysis: Robustness and generalizability of Web mining methods

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, a team of millirobots (TrainBot) is reported to 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. The first electrocauterization performed by the TrainBot is demonstrated 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.

Problem

• Magnetic millirobots enhance force for medical tasks
• Overcoming locomotion on slippery biological surfaces
• Collaborative robots enable minimally-invasive surgical procedures

Innovation

• Magnetic millirobots convoy
• Enhanced propulsive force feet
• Wireless magnetic actuation control