October 6, 2003

New engineering center focuses on implantable prosthetics

Devices for overcoming blindness, paralysis, and stroke damage are the focus of a new center

By Tim Stephens

Implantable microelectronic devices for overcoming blindness, paralysis, and stroke damage are the focus of a new center in which engineers from UCSC are collaborating with scientists at the University of Southern California and the California Insitute of Technology.

Developing prosthetic devices that interact with the nervous system requires a better understanding of astrocytes (shown here in green), the "helper cells" that play a critical role in development and maintenance of the nervous system. Red arrows at left point to astrocytes surrounding a blood vessel in a rat brain. Photo: M. Isaacson

In the retinal prosthesis, a chip implanted in the eye receives image data transmitted over a wireless connection from the high-tech glasses. Image courtesy of USC

The National Science Foundation (NSF) is providing $17 million over five years to fund the Center for Biomimetic MicroElectronic Systems (BMES), a national Engineering Research Center based at USC.

Biomimetics refers to the use of technology to mimic biological systems. BMES researchers are developing prosthetic devices to restore abilities that have been lost due to injury or disease.

The center will focus on three "testbed" projects: a cortical prosthesis for implanting in the brain to restore cognitive functions lost due to stroke or other causes; a neuromuscular prosthesis to restore movement to a paralyzed limb; and a retinal prosthesis to provide artificial vision to people who have lost their sight due to diseases affecting the retina, such as retinitis pigmentosa and macular degeneration.

"This is a most visionary engineering research center, where our faculty members and students will be working hand in hand with faculty at USC and Caltech on exciting, innovative, and critical research. It will lead to wonderful new technology that will be truly beneficial to mankind," said Steve Kang, dean of UCSC's Baskin School of Engineering.

Kang noted that the work of the new center is at the core intersection of the three broad areas in which UCSC's engineering school is focusing its expertise: information technology, biotechnology, and nanotechnology. The campus will receive about $2.7 million in funding from the center over the first five years. The center may receive NSF support for as long as 10 years, after which it is expected to become self-sufficient.

Wentai Liu, professor of electrical engineering, directs UCSC's participation in the new engineering research center. Photo by T. Stephens

All three of the center's testbed projects share common technological challenges, said Wentai Liu, a professor of electrical engineering and director of the center's activities at UCSC.

"The basic problems involve power and data management, miniaturization of the microelectronic systems, and the interface technology that allows the microelectronics to interact with living tissue," Liu said.

Liu has been working for more than a decade on the retinal prosthesis in collaboration with researchers at USC and other institutions. A prototype system has been tested in a small number of patients with promising results. It involves an internal unit that is implanted in the eye and stimulates inner-layer neurons of the retina, and a pair of high-tech glasses that acquire, code, and transmit images over a wireless connection to the implant. Electrical power is also transmitted wirelessly to the electronics in the eye.

The Engineering Research Center (ERC) provides stable, long-term funding for all three testbed projects and for addressing the basic technological challenges they all share, Liu said.

"The ERC enables us to plan long-term research and pursue a coherent interdisciplinary approach to difficult problems," he said.

Michael Isaacson, the Kapany Professor of Optoelectronics at UCSC and another key participant in the center, noted that the center is tackling problems that require collaboration between researchers in a wide variety of disciplines.

"All the exciting stuff is happening at the interface between engineering, biology, and the physical sciences," Isaacson said.

Isaacson has considerable experience doing research at this interface, using technology developed by the semiconductor industry to study biological systems and develop biomedical devices. His work involves developing nanofabrication techniques and imaging tools for making and visualizing devices and structures on the nanoscale (a nanometer is one billionth of a meter).

A major thrust of Isaacson's research has involved making connections between microelectronic devices and the nervous system. For example, he has developed devices that can be implanted into insect brains to record signals from the brain's neural circuits. Information about how the neural circuits work can then be used to develop improved microelectronic devices. This kind of feedback drives what Isaacson calls the nanobiotechnology cycle.

"It goes full circle. We use technology from the semiconductor industry to build a device to learn about a biological system, and then we take what we learn about the biology and apply it to develop a new device," he said.

Being part of this national Engineering Research Center is a significant achievement for the young Baskin School of Engineering, established at UCSC in 1997.

"This represents a quantum jump for the UCSC engineering program," Liu said.

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