A device being developed by a team of researchers from the University of Houston Cullen College of Engineering could make it unnecessary for more than 23 million diabetics to submit to daily finger pricks to test glucose levels in their blood.
The researchers received a three-year, nearly $400,000 National Science Foundation grant this month to explore the development of the implantable device, designed to use optical sensing to continuously monitor glucose levels.
“The ability to detect biologically modulated signals from beneath tissue will allow for the development of implantable biological sensors that overcome the need for frequent blood sample collection,” said Kirill Larin, assistant professor of mechanical and biomedical engineering and principal investigator on the project. “The device would look something like a wrist watch and be able to continuously monitor glucose levels. If glucose levels were to reach too high or too low, it would set off an alarm.”
A chronic disease with no known cure, the American Diabetes Association reports the disease affects close to eight percent of the United States population increasing their risk of developing life threatening complications such as stroke, heart disease, nervous system damage and kidney disease.
Larin is partnering with Paul Ruchhoeft, associate professor of electrical and computer engineering and Richard Willson, professor of chemical and biomolecular engineering, on the research in an effort to make monitoring the diabetes easier and help to reduce mortality and other complications of the disease.
“Continuous glucose monitoring is a long sought goal in diabetes,” Larin said, noting the devices existing to date are not a long-term solution or a replacement for daily blood sugar monitoring.
However, their device could be.
One of the main components of their system is a five micron sized, corner cube retroreflector. Smaller than a human hair, the cube-shaped retroreflector is covered on three sides with a reflective coating of gold nanoparticles. The surface allows for light to be reflected back to a system based on Optical Coherence Tomography (OCT).
Despite human tissue’s tendency to cause light scattering, making it harder to get the signal strength necessary for continuous glucose monitoring, OCT’s high-sensitivity is able to overcome this.
Similar to an ultrasound, OCT uses light rather than sound to create images. Light reflects off of tissue and is captured by a detector. Image analysis software then combines the signals from the reflected light to form an image in real time with a resolution up to a few micrometers.
But before the device becomes a daily tool for diabetics, the researchers must study the best ways for the system to be efficient. They are using tissue-simulating media to test the retroreflectors and determine the size and depth these tiny devices will be most effective under the skin.
“Little is known about contrast mechanisms from retroreflectors and OCT,” Larin said. “The combination represents a path to developing this technology into a viable implantable diagnostic tool. We are trying to develop a fundamental understanding necessary for a successful transition of this technology into practice.”