Soft Robot Biodegrades Inside Body

Researchers at the City University of Hong Kong have developed a magnetic soft millirobot that can grab and release objects, and move around by rolling. The device can be controlled using magnetic fields, and consists of a biodegradable gelatin and iron oxide microparticles.

The technology has significant potential as a minimally invasive drug delivery system, perhaps in the gastrointestinal tract, and may even lead to soft robots that can carry out surgical procedures within the body. One of the nicest features of the device is its rapid biodegradation over the space of a couple of days, which means that it may not have to be retrieved after serving its function in the body, instead breaking down into harmless constituents.    

Soft robots are the icky and ever so slightly disturbing cousins of their more traditional rigid counterparts. While they may appear to resemble a sea creature from the darkest depths of an ocean trench, they have enormous potential as a medical technology, with the ability to interact with our soft tissues without causing damage. In the fields of drug delivery and minimally invasive surgery, these robots could provide a sophisticated means to access and treat areas of the body that would otherwise be tricky to target.  

This latest offering is an early iteration of such technologies. The new millirobots are approximately as wide as a finger, and bear an uncanny resemblance to the aforementioned sea creature. They include an insect-like claw that can grab and transport objects. The robots can move by rolling and folding, and can navigate their way through body cavities, such as the gastrointestinal tract.      

Consisting of a natural material, gelatin, the millirobots can biodegrade in as little as two days in water, paving the way for medical procedures that do not require a follow-up surgical procedure to remove the millirobot afterwards.

Iron oxide microparticles within the gelatin structure make the robot highly responsive to magnetic fields, allowing it to be manipulated. The magnetic fields cause the microparticles to pull and distend the gelatin structure, resulting in ‘legs’ that can bend and move.  

So far, the Hong Kong researchers tested the technology as a drug delivery device, coating it in a drug solution and then using magnetic fields to move it through a model of the gastrointestinal system. When the robot reached the target region of the ‘gut’ it unfurled, releasing the drug.

See a video about the system below.

Study in ACS Applied Polymer Materials: Soft Tunable Gelatin Robot with Insect-like Claw for Grasping, Transportation, and Delivery

Via: American Chemical Society

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