Scientists develop a millirobot out of soft and biodegradable materials that dissolve after its intended use. They also design it in a way that it can grab, roll and climb. The study was published in the ACS Applied Polymer Materials.
Soft Millirobots Limitations
The biomedical industry has created soft, magnetic-field-powered millirobots. These robots' distinctive shapes enable them to roll or inch their way through the wavy tissues of our digestive tract. The drawback of these millirobots is that they are constructed from non-biodegradable materials like silicone. Surgery is required to remove it from inside the body as a result. The materials' lack of flexibility and inability to be precisely tailored are further drawbacks.
Better Materials for Soft Millirobots
In the most recent development, the researchers created the millirobot using a gelatin solution combined with iron oxide microparticles. According to Wikipedia, iron oxides are common in nature and are essential to numerous geological and biological processes. They are found in hemoglobin and are employed as iron ores, pigments, catalysts, and thermite.
The solution's microparticles pushed the gel outward as they positioned the item above a permanent magnet. It thus developed legs resembling an insect along the magnetic field's lines. The hydrogel was then exposed to cold to solidify it. The final step was soaking the material in ammonium sulfate to strengthen the hydrogel by causing cross-linking.
The flexibility of this substance is a plus. For instance, the researchers could fine-tune their results by altering the ammonium sulfate solution's composition, the gel's thickness, or the magnetic field's strength.
A distinct outcome may also result from where the hydrogel is placed. As it got further away from the magnet, there were fewer but longer legs. When a magnet is moved close to the hydrogel, the iron oxide microparticles in the gel generate magnetic chains that cause the legs of the magnet to flex and produce a gripping motion.
Soft Millirobots Mechanism
The experiment showed that a 3D-printed cylinder and a rubber band might be gripped and moved to different areas. The millirobot was also tested to dispense medication by covering it in a dye solution and rolling it through a model stomach. The robot strategically used magnets to unfold and release the color when it reached its location. Because it's made using water-soluble gelatin, the millirobot easily decomposes in water in two days, leaving only the minute magnetic particles.
Stanford University Develops a Millirobot that Swims
A mechanical engineer at Stanford University created one of the millirobot prototypes and included a magnetic crawling robot that was worming its way through a stomach. The specifics of this work were published in Nature Communications.
According to the description, the robot can negotiate barriers inside the body and self-select different locomotive states because magnetic fields drive it. This permits continuous motion and can be used right away to generate torque.
It is a versatile device that can electronically drive itself while transferring liquid medications, quickly move across an organ's rough, slick surfaces, and swim through bodily fluids. This robot holds back medication until it approaches the target and then delivers a high-concentration medicine.
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