HEMATOLOGY
Large artery
A Fantastic Voyage
Could tiny magnetic “ microwheels ” be the latest breakthrough in treating strokes ?
In more than a quarter of stroke patients , conventional treatment options are ineffective at breaking up blood clots . Keith Neeves , PhD , is working to change that through a potential new treatment dubbed “ microwheels .” These rotating clusters of magnetic beads that can be guided toward clots using magnetic fields have already produced impressive results in animal models : A clot that might have taken an hour to break up now takes about a minute .
In the 1965 film “ Fantastic Voyage ,” a group of scientists shrinks to microscopic size to navigate a tiny submarine through a defected soviet spy ’ s vasculature , saving him from a massive stroke by using lasers to break up a blood clot in his brain .
“ That ’ s the origin of this idea ,” says bioengineer Keith Neeves , PhD .
Inspired by the film , Neeves has spent the last eight years working with a cross-disciplinary team of mathematicians , biologists , clinicians , nurses , engineers , students and postdocs to find new approaches to treating strokes that occur in small blood vessels . Instead of a shrink ray and lasers though , Neeves employs tiny magnetic beads that , when exposed to a rotating magnetic field , form what he calls “ microwheels .”
Injection
Assembly
Neeves hopes that one day these magnetic beads — made of plastic and iron oxide and roughly the size of a blood cell — can be injected into a patient ’ s blood stream and directed toward blood clots . Once in their wheel configuration , the particles act as a swarm , and by altering the magnetic field , Neeves can control the swarm ’ s behavior .
“ Over the years , we ’ ve figured out ways to manipulate that magnetic field to make the wheels do all kinds of different things ,” Neeves explains . “ We can get them to roll in any direction and there ’ s some modes where they ’ re good at climbing walls . There are other modes where they ’ re good at penetrating into surfaces and there are modes where they roll really fast .”
The magnetic field is powered by copper wire repurposed from audio speakers , which is wrapped around cylinders that Neeves can control with a simple joystick . As he moves the field , the swarm of microwheels follows suit .
4 | CHILDREN ’ S HOSPITAL COLORADO