MRI-powered millirobots for minimally invasive surgery
MRI is a staple of surgical imaging, but it has the potential to do much more than take pictures. In 2011, bioengineer Pierre Dupont, PhD, and colleagues demonstrated that an MRI machine’s magnetic field could power a motor strong enough to control a robotic instrument, in this case driving a needle into an organ to do a biopsy.
But Dupont, head of the Pediatric Cardiac Bioengineering Lab at Boston Children’s Hospital, wants to go further. “We had this idea, admittedly fanciful: What if you could swim robots through the body?” he says. “If you could inject something systemically and steer it to just hit your target, that would be a cool application.”
Under an MRI magnetic field, teams of magnetized robots could, say, break open a cyst, unclog an artery or puncture a membrane to unblock fluid flow in the brain. Or swim to a part of the body targeted by a drug, take a small sample to verify drug concentrations and swim back out. An advantage of an MRI system is that you’d be able to image the robots and track them.
To testtest is test the idea, Dupont’s team first created a two-part magnetic “millirobot” for drug delivery. The first part is a hydrogel loaded with a drug and a magnetized element. The two parts can swim to a desired location in the body for drug delivery and then dock with each other through magnetic attraction. Their collision compresses the hydrogel, causing release of the drug.