Miracle Workers

ASEE Prism, Feb 2004 by McGraw, Dan

Bioengineers are developing microelectronic devices that could lead to amazing medical breakthroughs, including rudimentary sight recognition for the blind and, for the paralyzed, the ability to reach and grab.

WHEN C.L. MAX NIKIAS, dean of the University of Southern California (USC) college of engineering, speaks of the prospects of implantable microelectronic devices to help alleviate human suffering and treat incurable diseases, he sounds almost biblical. "Our very ambitious goal is to help the blind see, the paralyzed walk, and to restore the function of memory," Nikias says.

The technology behind these devices is still in its infancy. The steps being taken now are within the realm of preventing muscle atrophy through electrical stimulation, and regenerating tissue damaged by disease. And despite Nikias's hope, no one is predicting that paraplegics will have full use of their muscles any time soon.

But the prospect of great medical breakthroughs from this bioengineering research is more than just wishful thinking. So real are the prospects that the National Science Foundation recently awarded a five-year, $17 million grant to fund the new Biomimetic MicroElectronic Systems (BMES) Engineering Research Center at USC. The center will be a collaborative effort among USC, The California Institute of Technology, and the University of California-Santa Cruz (UCSC).

The desire to alleviate the worst in human suffering has always been of paramount importance to scientists in the engineering and medical community. Work in the past has been primarily auxiliary in nature-from high-tech wheelchairs and breathing aids for paraplegics to chirping traffic signals to help the blind cross the street safely. The BMES project will undertake research that might eventually lead to a better understanding of how the brain and physical tissue work together, and perhaps lead to cures for currently incurable maladies.

The BMES project is very much a collaborative effort, combining the skills of biomedical engineers, electrical engineers, and research physicians. For engineering students at the three schools, the prospect of hands-on biomedical engineering research in the groundbreaking project is exciting. "What we are going to have in the research project is the ability for students to come and see patients," says Mark Humayun, professor of ophthalmology, biomedical engineering, and cell and neurobiology at USC, and the director of BMES. "My focus in teaching in this field is to tell students, 'solve this human suffering.' We want students to see how blind people suffer and get through life; we want them to see the real consequences of a person confined to a wheelchair. This is a powerful motivator for students. That's what drives innovation. That's what drives medical breakthroughs." Researchers like Humayun, who has a background in medicine and engineering, are the backbone of BMES.

Though helping the blind see and the lame walk are long-term goals, the research during the next five years will concentrate on three "test-bed" projects: a retinal prosthesis that could reverse cell degeneration caused by eye diseases; an injectable microelectronic stimulator to aid stroke victims; and a cortical silicon chip prosthesis to take over the function of neurons lost to disease or injury.

Gerald Loeb, a professor of biomedical engineering at USC, has been working on a microelectronic device called a BION, short for bionic neuron. BIONs are tiny glass capsules about the size of a grain of rice, implantable within tissue with a 12-gauge needle, and activated by a radio signal through inductive coupling from a coil worn by the patient. BIONs produce an electrical stimulus that is capable of 3,000 different commands per second.

The initial research centers on using electrical stimulation from BIONs to rebuild the strength in the muscles of stroke victims. Eventually, researchers would like to use BIONs to help paraplegics walk. "About the last thing that will be done with this technology is the possibility of making paraplegics walk," says Loeb. "People in wheelchairs face many life-threatening complications, things like pressure sores, deep vein clots, pneumonia from not being able to cough properly, and bowel and bladder function."

Loeb believes the alleviation of these life-threatening symptoms through the electrical stimulation of the afflicted tissues is the best prospect for the first generation of BION research. Researchers hope that future generations of BIONs will restore function to paralyzed hands, arms, and legs.

USC biomedical engineer Rahman Davoodi is studying computer simulations of moving human limbs. The research might lead to an understanding of how much electrical stimulation of a muscle or a nerve is needed to make a hand grip or a leg stand.

Sight to the Blind

THE RESEARCH INTO a retinal prosthesis for people who have lost sight to disease involves an implantable microelectronic device that stimulates the inner-layer neurons of the retina. The patients wear a pair of high-tech glasses that receive, code, and transmit images over a wireless connection to the implant. Electrical power is also supplied to the microelectronic implant through this connection.