Medical Device Link.

SPECIAL REPORT

A Canadian start-up company is developing a self-sustaining fuel cell to power implantable devices. Potential applications range from drug-delivery devices to neurotransmitters. “Our technology is, as far as I know, the only silicon-based fuel cell that generates electricity from the glucose in the bloodstream,” says Thomas (Yong-il) Ahn, CEO of Sweet Power (Victoria, BC, Canada). “Most companies that are developing alternative energy sources for implantable medical devices are using enzymes to generate electricity,” he says. “Those systems generally can produce power for only a few days.”

The company’s patent-pending fuel cell technology, in addition to having a potentially unlimited life span, has a number of advantages over other power sources for implantable devices. For instance, lithium and other types of batteries, which have a life span of a few years, contain toxic materials and are often bulky. Conversely, the company’s fuel cell is inherently biocompatible and nontoxic. “And the inputs for our fuel cell are oxygen and glucose and the outputs are water and carbon dioxide,” Ahn explains. The company’s most recent prototype measures 1 × 1 cm. Because the fuel cell is based on silicon-chip technology, it can be scaled down to nanoscale dimensions. Last year, the fuel cell won the Nano Science and Technology Institute’s Nanotech Ventures Award in the health and medical category at a ceremony in Santa Clara, CA, USA.

Unlike conventional batteries, the fuel cells are compatible with MEMS (microelectromechanical systems) technology, which is being used for a growing number of medical applications. “Because MEMS are, by definition, very small, they are difficult to attach to other power supplies,” Ahn explains. Conversely, the firm’s power supplies can be integrated on the same wafer as MEMS–based medical devices during production. “Not only will this ensure a high yield of functioning devices, it will reduce or eliminate the need for manual assembly,” Ahn says.

The company has built prototypes that can generate electricity from sugar water. The chief technical officer of the company, Mu Chiao, is fixing leading research to develop a model that can generate electricity from the glucose in blood plasma. “The challenge that we have now is that there are a lot of proteins in the blood that clog up the fuel cell,” Chiao explains. The inventor of the microfabricated microbial fuel cell, Chiao is also a professor of mechanical engineering at the University of British Colombia (Vancouver, BC, Canada). Ahn expects that it will take 12 to 18 months to develop a prototype that is ready for animal testing and that human testing will follow about five years after that.