Magnetic microbot somersaults through the colon to deliver drugs
Using tiny robots to deliver drugs is promising pathway when it comes to limiting side effects and increasing effectiveness, and some take a more theatrical approach than others. Scientists at Purdue University have come to the party with a back-flipping microbot that can tumble its way through the colon to release its payload when desired, all while being controlled externally by a magnetic field.
Minuscule robots that can be loaded up with therapeutics, sent to a precise location in the body and then release medication as needed could mean big things for the treatment of many diseases, and there’s no shortage of inventive solutions on the horizon. We’ve previously looked at corkscrew-inspired robots that skewer cancer cells to drop drugs inside, others that can crawl, roll and jump, and ones that creep along like a caterpillar.
Back in 2018, we looked at a magnetic microbot from Purdue University that moved via a tumbling motion, which enabled it to overcome uneven terrain and even take on steep inclines, demonstrated in dry air and silicone oil. The same research group has continued to improve the technology, and has now demonstrated its capabilities in biological tissue for the first time.
The researchers chose the colon for their first in vivo experiments, because of the easy access and also because its messy nature poses a unique challenge.
“Moving a robot around the colon is like using the people-walker at an airport to get to a terminal faster,” says study author Luis Solorio. “Not only is the floor moving, but also the people around you. In the colon, you have all these fluids and materials that are following along the path, but the robot is moving in the opposite direction. It’s just not an easy voyage.”
The team was able to demonstrate its robot in the colons of mice placed under anesthesia, with the tiny machine coated in mock drugs and inserted via the rectum inside a saline solution. The robot is made from polymer and metal and needs no battery or power source, instead being powered and controlled with magnetic fields from outside the body, with the scientists using ultrasound equipment to observe its movement. These results were also replicated in colons removed from pigs, which the team notes have similar characteristics to humans.
“We were able to get a nice, controlled release of the drug payload,” says Solorio. “This means that we could potentially steer the microrobot to a location in the body, leave it there, and then allow the drug to slowly come out. And because the microrobot has a polymer coating, the drug wouldn’t fall off before reaching a target location.”
In addition to delivering drugs, the researchers also believe the robot could one day be useful in diagnostic applications, by helping to collect tissue.
The video below provides an overview of the research, which was published in the journal Micromachines.
Source: Purdue University
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