Kenichi Takahata may not be a physician, but he knows medicine from the inside out. An assistant professor in the Department of Electrical and Computer Engineering at the University of British Columbia, Dr. Takahata builds miniature devices that integrate electronics and mechanics. He spends much of his time researching biomedical applications, with an emphasis on implants.
Along with two vascular surgeons from Vancouver General Hospital, Dr. Takahata and four other UBC faculty members have developed a "smart" version of the cardiac stent, a tube that physicians implant to expand clogged coronary arteries. Their stainless-steel prototype contains micro-sensors that wirelessly monitor conditions inside the arteries and warn if the stent is failing.
Dr. Takahata is also working on a wireless implantable drug-delivery device. Controlled by radio-frequency power, the micro-electro-mechanical systems (MEMS) implant is just 1 centimetre wide by 1 millimetre thick. By turning on its micro-nozzles, a clinician can dispense a drug at a targeted location inside the body. Dr. Takahata and his colleagues have fashioned the device from a biocompatible polymer so its presence doesn't harm the patient.
This biomedical implant may lend itself to cancer treatment, Dr. Takahata explains. Because it pinpoints disease sites and delivers drugs in such precise doses, it could dramatically improve chemotherapy – with far milder side effects than traditional methods.
"Another application we're looking at is pain control," says Dr. Takahata, a Canada Research Chair in Advanced Micro/Nanofabrication and MEMS. "That is also related to cancer therapy, because pain management is really important in the field."
Powered by advances in biomaterials and microelectronics, biomedical implants have the potential to transform everything from drug delivery to orthopedics and neurology. They're crucial to new treatments that will help meet the challenges posed by an aging population – and transform the practice of medicine.
There's a strong business case for developing biomedical implants, notes Paul Santerre, director of the University of Toronto's Institute of Biomaterials and Biomechanical Engineering (IBBME). Through 2014, the American market for implantable medical devices will grow more than 8 per cent annually to $49-billion (U.S.), according to Cleveland-based market research firm the Freedonia Group.
Globally, researchers are zooming in on several key areas, says Prof. Santerre, who oversees Canada's largest biomedical program. They're developing devices for aging patients, especially stents and other cardiac implants.
Another burgeoning field is orthobiologics, Prof. Santerre explains. Its applications include the use of anti-microbial agents with orthopedic implants to treat degradation of bone structure around the healing area, he says.
Dr. Santerre is also excited about real-time diagnostics, combination drug-delivery devices that use biomaterials and neural implants and therapies. "The whole area is getting ready to explode as a result of an aging society and Alzheimer's and other kinds of dementia and diseases that begin to show an onset as we roll into our 80s," he says.
At IBBME, which has 36 core and 55 cross-appointed faculty affiliated with 10 teaching hospitals, many scientists do research connected to biomedical implants. For example, rehabilitation technology sciences team leader Milos Popovic has helped quadriplegic patients regain upper-body movement by administering regular electrical stimulation to their tissues.
"We're conceiving systems that would be implanted for anywhere between a week and four months, depending on what we're trying to achieve," Prof. Santerre says.
Looking ahead, Prof. Santerre sees great promise for tissue engineering, another implant-related IBBME research area.
He believes that by 2020, it will be possible to implant a new coronary artery built by your own cells. "[For]more complex organs, it's going to take a bit longer, but we're getting there."
At Duke University in North Carolina, biomedical engineering professor Warren Grill studies deep-brain stimulation with a biomedical implant that he calls a pacemaker for the nervous system. Clinicians have used deep-brain stimulation to treat about 80,000 people for movement disorders including Parkinson's disease and essential tremor, Dr. Grill says.
Technologically similar to a cardiac pacemaker, the deep-brain stimulation device consists of a programmable, battery-powered stimulator connected to an electrode. The stimulator, which is somewhat smaller than a hockey puck, gets permanently implanted in the patient's chest.
To treat motor disorders, the electrode runs under the skin to behind the ear, then through a hole in the skull to the appropriate part of the brain.
No one fully understands how deep-brain stimulation works, Dr. Grill says. Besides investigating that mystery, he and his team are fine-tuning the implant to give the right dose of stimulation for different patients and circumstances. "We've been working on a smart programming system to try to assist the clinician to get to the optimal parameters quickly," he says.
Next, Dr. Grill wants to give the device closed-loop control so it automatically adjusts its stimulation level to the needs of the patient.
Thanks to this biomedical implant, he says, neurology is on the cusp of a transformation like the one that swept cardiology during the early 1960s. Where they once only diagnosed patients and prescribed drugs, cardiologists began installing stents, pacemakers and defibrillators, Dr. Grill says.
"The idea is to develop technology to empower the neurologist to treat patients in the same way that the cardiologist was empowered 50 years ago."
From a commercial success to a trial balloon, these three products show how biomedical implants can dramatically improve people's lives.
Cochlear implants: Designed for the deaf and the severely hearing-impaired, these small devices let the user experience sound by directly stimulating the auditory nerve. As of last year, almost 220,000 people worldwide had cochlear implants, the U.S. Food and Drug Administration reports.
Wireless heart monitor: Atlanta-based CardioMEMS Inc. sells a wireless cardiac implant that it developed using MEMS (micro-electro-mechanical systems) technology. The surgically installed miniature sensor can help physicians manage cardiovascular illness by transmitting a patient's blood pressure, heart rate and other information.
Neurostimulator for epilepsy: When it detects an oncoming epileptic seizure, NeuroPace Inc.'s implantable neurostimulator returns brain activity to normal by delivering electrical stimulation.