Researchers at the University of Colorado Boulder have developed a new category of miniature, self-propelled robots that can swiftly navigate through liquids. These tiny robots hold the potential to deliver prescription drugs to inaccessible areas within the human body. The study detailing these advancements was published in the journal Small.
Lead author Jin Lee, a postdoctoral researcher in the Department of Chemical and Biological Engineering, envisions a future where microrobots can undertake non-invasive surgical tasks within the body. Instead of invasive procedures, the robots could be introduced via pills or injections to perform the required procedures autonomously.
Although the researchers are not yet at that stage, their recent findings mark a significant leap forward in the development of small-scale robots. Measuring a mere 20 micrometers in width, several times smaller than a human hair, these microrobots are incredibly fast, capable of traveling at speeds of approximately 3 millimeters per second or 9,000 times their own length per minute—an impressive feat even when compared to the relative speed of a cheetah.
The potential applications for these microrobots are vast. In the conducted study, fleets of these robots were employed to transport doses of dexamethasone, a common steroid medication, to the bladders of laboratory mice. The results suggest that microrobots could prove to be a valuable tool in the treatment of bladder diseases and other ailments in humans.
C. Wyatt Shields, an assistant professor of chemical and biological engineering and co-author of the study, emphasizes the allure of microscale robots lies in their ability to perform practical tasks within the body. He compares the concept to the movie Fantastic Voyage, released in 1966, where a submarine is miniaturized and traverses the body of a comatose man. Shields envisions microrobots navigating through a person's bloodstream, targeting specific areas for treatment.
The microrobots are constructed using biocompatible polymers through a technology akin to 3D printing. Resembling small rockets with three fins, they possess an additional feature—an enclosed air bubble, akin to the air bubble created when submerging an inverted glass in water. When subjected to an acoustic field, similar to ultrasound, the bubbles vibrate vigorously, propelling the robots forward by expelling water.
Other co-authors from the University of Colorado Boulder include Nick Bottenus, an assistant professor of mechanical engineering, Ankur Gupta, an assistant professor of chemical and biological engineering, as well as engineering graduate students Ritu Raj, Cooper Thome, Nicole Day, and Payton Martinez.
To assess the capabilities of their microrobots, the researchers focused on addressing a common human ailment—bladder disease. Interstitial cystitis, also known as painful bladder syndrome, afflicts numerous Americans, causing severe pelvic pain. Treatment often involves patients visiting a clinic multiple times over several weeks, where doctors inject a potent dexamethasone solution into the bladder via a catheter.
Lee believes that microrobots can potentially offer relief. In laboratory experiments, the team fabricated groups of microrobots encapsulating high concentrations of dexamethasone. They then introduced thousands of these bots into the bladders of lab mice. The microrobots dispersed throughout the organs, eventually adhering to the bladder walls, which could make them challenging to eliminate through urine.
Once attached, the microrobots gradually released dexamethasone over approximately two days. This controlled release could enable patients to receive a steady flow of medication over an extended period, leading to improved treatment outcomes.
Lee acknowledges that there is still substantial work to be done before microrobots can navigate through real human bodies. One of the primary goals is to make the robots entirely biodegradable, allowing them to dissolve
