Biosensor Could Help People with Parkinson's, Alzheimer's Disease
University of Arkansas release
December 1, 2005
FAYETTEVILLE, Ark. - An engineering researcher at the University of Arkansas has developed a wireless, implantable biosensor that may one day help physicians treat patients with neurological brain disorders such as Parkinson's Disease, Alzheimer's Disease and epilepsy. Made of carbon nanotubes, the sensor monitors and controls chemicals in the brain and communicates with other sensors to control tremors or direct the movement of prosthetic limbs.
Varadan recently came to the university from Penn State University because of UA's center of excellence in nanotechnology and funding from the Walton Family Charitable Support Foundation for establishing a laboratory for large-scale fabrication of carbon nanotubes and nanowires.
Varadan's carbon nanotubes and nanowires are hollow, light-weight, chemically inert and have great mechanical strength. They are grown and organized into arrays that are combined to make chips not unlike those found in computers and other electronic devices. Varadan's carbon chips are bio-compatible; the human body will not reject them as a foreign object. Several research projects have demonstrated that carbon fibers integrate into human tissue without causing significant foreign-body reaction.
Once inside the body, the chips perform several functions. They sense and monitor the release of essential chemicals produced by the brain, including dopamine. Otherwise known as a neurotransmitter, dopamine is a chemical that facilitates communication between neurons in the brain. A specialized set of neurons in the substantia nigra section of the brain are the source of chemical activity that controls normal movements of the body.
When neurons in the substantia nigra degenerate, there is a loss of dopamine. This loss of dopamine causes nerve cells to fire excessively, making it impossible for Parkinson's patients to control their movements. The loss of motor control is manifested in tremors or trembling hands, two of the primary symptoms of Parkinson's.
Varadan's carbon biosensor records the loss of dopamine and stimulates activity between neurons and neurites, which are immature, developing neurons. In addition to sensing the release of chemicals and contributing to the growth of healthy, dopamine-producing neurons, the biosensor communicates with an organic, polymer-based sensor attached to an area of the body in which a tremor occurs. The signal from the implanted sensor can control and direct the motion of the area of the body on which the exterior sensor is attached.
"This exterior sensor can be easily placed under a wrist watch," Varadan said. "Essentially, the implanted, carbon-based sensor detects the sensor attached to the watch, controls the trembling and tells the hand where to go."
This same process could work for people who have prosthetic limbs, Varadan said. With the polymer-based sensor attached to a prosthetic arm, for example, a signal from the implanted biochip could direct movement and motion of the artificial arm.
The wireless technology has many applications. The location of Alzheimer's patients or any person wearing the exterior sensor could be continuously monitored by inserting the carbon-based sensor in an electronics device, such as a cell phone or computer connected to the Internet.
The biosensor can measure glucose levels from the skin's surface, which would eliminate the need to obtain a blood sample by lancing the skin. It also could help doctors and diabetes patients control delivery of insulin. Furthermore, the sensor could monitor and control chemicals that precipitate a stroke or epileptic seizure. Varadan said the chip also can control the release of medication, which could clean arteries and prevent an aneurism or heart attack.
Varadan has several patents pending for the technology, which is supported by multi-million dollar grants from private health-care companies. He is also pursuing approval from the U.S. Food and Drug Administration.
In addition to holding the endowed chair and his appointment as a distinguished professor, Varadan is director of the university's High Density Electronics Center and a professor of neurosurgery at University of Arkansas for Medical Sciences in Little Rock.
This story is derived from an Oceana. This original version appears at Biosensor Could Improve Lives of People with Neurological Brain Disorders.