Improving on Implants

Dr. Kenichi Takahata and his multi-disciplinary collaborators from engineering and medicine are exploring revolutionary techniques to assess and control the operation of medical implants.

Takahata is an Assistant Professor of Electrical and Computer Engineering at the University of British Columbia and holds a Canada Research Chair in Advanced Micro/ Nanofabrication and MEMS. Through exploiting MEMS technologies, he’s developing life-saving therapies for difficult to treat conditions. “It’s important to monitor medical devices after implantation, but there’s currently no good way to continuously monitor how they perform.” he says.

A key example is the stent, a tiny tube-shaped wire cage that is inserted into a blood vessel whose inner walls have become so thick with fatty deposits that they could cause a catastrophic circulation stoppage. Once the stent is in place, it expands to restore the blood flow. Tracking the ongoing performance of this solution has remained difficult; patients must usually undergo an expensive, invasive procedure, which includes the injection of a dye into their bloodstream so X-ray imagery can reveal how the stent is performing. Takahata is proposing a more efficient alternative, which he calls the “smart” stent. The device is outfitted with a MEMS microsensor to measure movement and pressure and data is continuously transmitted wirelessly by using the stent structure itself as an antenna, or a “stentenna”.

His team has pioneered groundbreaking research into brain aneurysm sensors that could enhance metallic embolization coil treatments. An aneurysm occurs when blood vessels bulge; ruptures are potentially life threatening. A wireless sensor could detect the re-entry of blood into an aneurysm, signaling the failure of the embolization treatment. The research is iterative and the team is working towards a prototype.

“These kinds of technology advancements could provide a huge benefit to the patient and the physician, permitting them to accurately determine the real-time status of the stent or aneurysm embolization and take necessary action.” he explains.

The research activity of the Takahata Laboratory also includes extensive work into micro-actuators that are crucial to the operation of another type of implant, one which would provide drugs with doses and timings tailored to a patient. Such implants could make life much easier and safer for patients undergoing chemotherapy for cancer and its pain management, adding a new degree of control to the timing and size of their dosage. “Potentially we can achieve very accurate drug delivery control and more effective therapy,” he says. “We have developed a new way to manipulate the micro-scale actuators for pumping and valving wirelessly, using radio waves.”

Since working test models of MEMS devices can be time-consuming and difficult to build, much of their design and calibration has been completed virtually, using a piece of simulation software called COMSOL. CMC Microsystems’ support has provided the members of Takahata’s team with access to this vital tool, which conducts finite element analysis to yield accurate predictions of how a complex system will perform. Also, using the microfabrication assistance, CMC has played a prominent part in the development of Takahata’s ideas through supporting the fabrication of the crucial sensors and drug-delivery devices that characterize these innovations.

Takahata and his colleagues are investigating micro-plasma fabrication techniques to use with carbon nanotubes and are also incorporating magnetic fluid into MEMS devices for enabling high-performance actuators and sensors in microfluidic applications. The group can envision tremendous applications for core technologies and continue to investigate broader uses, bringing forward advances in diagnostic and therapeutic medical technologies to improve the quality of human life and taking steps for eventual transfer of technology to industry.