Medical implants from our own cells?
Ohio State University researcher: A biological solution to a biological problem.
When Loretta COLUMBUS —
Garside’s essential tremor kicks in, it sends the 59-yearold’s body bouncing uncontrollably around the room
— feet tap-dancing and limbs rattling.
And the tremor wracks her like a seizure until she falls asleep, she said.
“Except I don’t lose consciousness; I’m awake, and I’m aware,” said Garside, who lives in Sunbury, Pennsylvania. “It feels like somebody else steps into my body.”
Before Garside received a neurostimulator implant about 20 years ago, the fits left her in a wheelchair, too exhausted to dress herself. At times, she had no voice for weeks.
Her symptoms are more manageable with the electronic device, but it’s a shortterm solution and requires the constant replacement of batteries and wires.
Ohio State bioengineer Liang Guo thinks there’s a more natural remedy for patients such as Garside who are afflicted by Parkinson’s, Alzheimer’s, epilepsy, severe tremors or traumatic brain injuries.
“You should use a biological solution to solve a biological problem,” he said. “We should use cells designed by nature.”
In the summer, Guo received a $500,000 Department of Defense grant to study whether scientists could engineer living tissues into lab-grown, transplantable cellular circuits to be used in patients with nervous-system disorders.
“How can we use cells to build devices? We want to learn how nature engineers, and master that capability,” Guo said.
Current neural prosthetics involve implanting electrodes into the body that interact with the nervous system — including the brain and spinal cord — through electronic pulses transmitted by thin wires.
Because the devices are electronic, they don’t coexist peacefully with the body, Guo said. Over time, scar tissue wraps around the electronics. The body also can begin to reject the foreign object, or tissue around it can become inflamed. And the technology needs regular maintenance, he said.
Garside knows firsthand that deep-brain stimulation technology is not without defects.
Her early model would physically shock her body when she got too close to automatic doors at the grocery store or when a military aircraft whizzed over the house.
Violent tremors have cracked wires in her neck and chest, and body fluid has infiltrated the pack.
She also needs a week to recover from surgery when doctors swap out the device’s batteries every 18 months.
And Garside gets the sensation of having a stroke during her regular, twicea-year adjustments.
“It’s sort of traumatic,” she said. “But I couldn’t have a life without it.”
Guo is exploring whether a device made with a patient’s own cells and modeled on natural circuits could eliminate some of the drawbacks of current technology.
“You don’t need a battery. You don’t need to replace the components over time because they’re made with your body,” he said. “It will be a permanent cure to neurological diseases.”
Before they begin any engineering work, Guo and the researchers in his lab are harvesting neurons from the spinal cords of Aplysia sea slugs.
The neurons from the slug are relatively big, with a diameter of 100 micrometers or more, compared with 5 micrometers for mammals. After they’re harvested, the scientists then will use the dissembled neurons to reconstruct the original neural circuit, program its function and transplant it back into a recipient.
Guo said it could be a decade or more before scientists can engineer cellular brain implants to treat patients with a variety of neurological diseases.
“First, we need to learn from nature,” he said. “Then we ask, ‘Can we reverse-engineer these circuits?’”
Guo said his research group is one of only a few studying how tissue-based devices might replace electronic neural implants.
“There is no field for this type of work. This concept is too frontier,” he said. “Even I was skeptical at first.”
Elsewhere at Ohio State, another cutting-edge lab focuses on building unobtrusive devices that can unpack, monitor and stimulate brain signals.
Asimina Kiourti, an assistant professor in electrical and computer engineering, said her research team is developing wearable sensors and battery-free implants that can pick up signals from thousands of sites across the brain.
This week, she and Guo will co-host a lab tour and discussion of brain-implant technology.
“We’re trying to understand the brain better and improve its functionality,” Kiourti said, adding that researchers still know very little. “Right now we’re finally growing. We’re looking forward to seeing where all this research goes.”