Tiny Fish-Inspired Robots Navigate Through Body to Deliver Targeted Drug Therapy

Miniature robots small enough to travel inside the human body have long been viewed as a future cornerstone of precision medicine. However, most existing soft robots operate alone, limiting how well they can navigate complex anatomy or deliver drugs effectively. Now, new research has demonstrated how coordinated robotic swarms can overcome these challenges to deliver highly targeted therapy.

In a major advance, researchers at Harbin Institute of Technology (Harbin, China) have developed fish-like soft robots that work together as intelligent swarms capable of navigating tight spaces, locating diseased tissue, and reshaping themselves for precise drug delivery. Inspired by the coordinated migration patterns of fish, the team designed 2-millimeter miniature robots that can self-organize into swarms, disperse when needed, and reunite at target sites deep within the body.

The robots’ movements are powered and controlled by external magnetic fields, enabling noninvasive guidance through complex biological environments. To achieve true swarm behavior, the researchers tuned the robots’ response to magnetic fields so that, near each robot’s natural resonance frequency, their swimming direction becomes governed by a single constant magnetic component. This allows different robots to move in different directions simultaneously under one global control field, enabling coordinated navigation across large areas.

Each robot is capable of six degrees of freedom — pitching, yawing, rolling, and translating vertically, horizontally, and forward — with swimming speeds similar to those of natural fish. When dispersed, the swarm can slip through narrow bodily passages, then reassemble and adapt its collective shape to match the contours of lesions or tumors for optimized drug delivery.

Laboratory and ex vivo experiments showed how the swarm could navigate to a simulated gastric lesion, aggregate precisely at the site, and conform to its boundaries to improve contact-based therapeutic delivery. The research, published in National Science Review, reveals how swarm robotics could one day enhance the treatment of hard-to-reach diseases with minimal invasiveness.

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Harbin Institute of Technology