MRI-powered millirobots hopes to heal in non-invasive way
UH roboticists are developing a new form of non-invasive interference and drug delivery, using MRI-powered millirobots injected into the body, allowing patients to heal from the inside.
The most common brain surgery to cure such blockages like Hydrocephalus— or excess water (cerebrospinal fluid) that accumulates within the ventricles of the brain— requires cutting a hole into the scalp leaving a small scar behind for many patients. The roboticists hope to change this with their millirobots in a non-invasive procedure.
The Cullen College of Engineering’s electrical and computer engineering professor Aaron T. Becker, along two researchers at Harvard Medical School, developed a self-assembled Gauss gun, which injects these millirobots through the spinal canal, moving up “like ship channels throughout the body (floating in CSF),” magnetized and manipulated by the MRI scanner.
“The cardinal rule for MRIs is (to) never take anything magnetic inside,” Becker said.
Because MRI scanners have strong magnetic fields, deaths have been reported when patients with undetected metal in their body enter an MRI scanner— making this a risky task.
“What we decided to do, as roboticists, was to purposely introduce small pieces of metal inside the MRI and then use the MRI to both see those pieces of metal and apply forces to steer them around inside somebody’s body,” Becker said.
The researchers initially struggled, finding that the MRI wasn’t powerful enough to penetrate the millirobots into the tissues on its own. The MRI magnets can only pull 40 percent of the power of gravity, Becker said, giving it a bit of weight, but not enough to pierce the tissue.
“I searched online, and found this thing called a Gauss gun,” he said. “They call it a magnetic canon, I call it a Gauss gun, because it was the name I first discovered.”
The magnetic accelerator, very much like a sugared-up Newton’s cradle, has three high-powered magnets that separate a row of lined steel balls — filled with potential energy — which amplify the force when the first steel bar-bearings gently hits the next ball and sets off a chain reaction, gaining momentum.
The last steel ball flew right into the standing three pins, which Becker printed from his 3D printer, and into his laptop with surprising speed.
“I should have probably moved this,” Becker said.
The self-assembled Gauss gun is designed with three 3D-printed plastic components—the trigger (that fires), barrel, and delivery (with the puncture and drugs) containing titanium rod spacers that splits up two steel balls.
“We’d like to bring tiny robots to the goal location, and then self-assemble them into a tool that we can use to treat diseases,” he said. “That tool that we’d like to make it one that can puncture kind of like an auto-injector (diabetic injection).”
Mathematical biology senior Laura Ramirez found this new procedure to be beneficiary, seeing how it could barely leave a scar, and how exciting it sounds.
“It sounds very much like a science fiction procedure having tiny robots navigating through your body to cure you,” Ramirez said. “The medical field could really change with this.”
It’s estimated that more than a million people in America suffer from Hydrocephalus, including one to two out of every 1,000 babies born according to the Hydrocephalus Association. The project, if successful, can operate on spinal cord blockages, brain injuries and even cancerous cells.
Doctoral candidate in Controls at the ECE Department, Shiva Shahrokhi has worked with Becker for a year and finds that if they can control thousands of robots simultaneously, they can achieve a medical impact.
“We could have millions of surgeons in our bodies that can potentially cure cancer in a short period of time,” Shahrokhi said. “You can put some micro robots into the blood and navigate them to the cancer cells and they can kill them without damaging their healthy cells and get them out. Our goal is to get to that stage.”
She laid down a couple of kilobots on a white board and illustrated how the tiny robots, which have two motors (such as vibrators in iPhones) navigated by the light to go either left, right or straight, each movement lights up by a color — red, blue or green.
“The same way the kilobots are navigated by light, the millirobots would be navigated by the MRI,” Shahrokhi said.
Commanding each robot simultaneously through global inputs is still a challenge that both Becker and Shahrokhi are working to strengthen.
“My lab’s goal is to work with smaller and smaller robots into this nanoscale and eventually control trillions of robots,” Becker said.
The next goal for Becker is to get animal testing started and finding further funding options; negotiations are currently under talks with MRIs in Houston, among other partnerships. Currently, Becker’s team is looking at how they can deliver pain blockers directly to individual nerves to temporarily block individual pain receptors.
“Having a tiny delivery vehicle that we can control opens a world of possibilities,” he said.