Miniature Robot Swimmers Heal Themselves, May Help in Surgeries and Other Medical Applications

One of the organic capabilities that have been difficult to replicate in artificial systems is the ability to heal and regenerate itself - and now a new design for robot swimmers might be able to do just that.

Researchers from the University of California San Diego have reported the development of "2D self-healing small-scale swimmers" capable of moving by themselves and magnetically reattach broken parts on-the-fly. With this new technology, future robots can move and heal themselves could make for more durable robots for environmental or industrial applications.

Proponents of the study detail the development of these miniature swimmers in the latest ACS Nano Letters in a report titled "Swimmers Heal on the Move Following Catastrophic Damage."

Miniature Swimmers For A Variety of Applications

The UC San Diego researchers developed these small robots capable of swimming through fluids to carry out their tasks such as cleaning, picking up and delivering materials and drugs, and even performing surgery. While most of their development and testing has been conducted in the laboratory, these miniature swimmers that heal themselves will eventually be tested in real-world environments. The harsh environments are expected to damage these robots.

Existing robot swimmers are usually made from brittle polymers or soft hydrogels, with either material unfortunately prone to cracking or tearing. Joseph Wang, together with colleagues from UC San Diego, looked for design choices that could lead to design swimmers that can heal themselves on the fly without external triggers or manual inputs from human controllers.

Their resulting design led to swimmers that were only 2 centimeters long or almost the same as the average human finger width. These swimmers - designed in the shape of a fish - are equipped with a conductive bottom layer, a rigid and hydrophobic middle layer, and an upper layer containing aligned and strongly magnetic microparticles. An alloy of neodymium, iron, and boron was used in specially fabricated strips to allow the robots to heal themselves.

Additionally, researchers used platinum in the fishtail, which reacts with hydrogen peroxide used as the fuel, forming oxygen bubbles that propel the robot to move through the fluid where they are released.

Testing its Ability to Move and Heal Autonomously

Researchers placed sample robot swimmers in a petri dish to test its mobility, containing a weak hydrogen peroxide solution. They observed these miniature swimmers move around the sides of the dish. Next, researchers cut the swimmer using a blade. The tail kept moving on its own until it found its other half, reattaching it and returning to the original fish shape through a magnetic interaction between the separated parts.

Furthermore, researchers also tested whether the robot swimmers could heal themselves when cut into three pieces or changed the magnetic strips' configuration - they did. According to the researchers, the versatile, fast, and simple self-healing strategy they demonstrated with these small-scale swimmers could be an important step toward on-the-fly repair for swimmers and robots.

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