Shining a Light on Diabetes

Researchers from Massachusetts Institute of Technology recently advanced a major step towards minimizing pain and inconvenience for patients with type 1 diabetes. Such people must keep a careful eye on their blood glucose levels, and therefore they are required to prick their fingers several times a day to draw blood for testing. Now, using a new device, they could use a noninvasive way that relies on light to measure blood glucose levels.
MIT researchers have devised a way to measure blood glucose levels by shining near-infrared light on the skin. (Credit: Patrick Gillooly)
MIT researchers have devised a way to measure blood glucose levels by shining near-infrared light on the skin. (Credit: Patrick Gillooly)

Type 1 diabetes is a form of diabetes mellitus that results from autoimmune destruction of insulin-producing beta cells of the pancreas. The subsequent lack of insulin leads to increased blood and urine glucose. Thus, it is required from diabetes patients to constantly monitor their glucose level, to keep track of their medical status.

The research team, from Massachusetts Institute of Technology (MIT) Spectroscopy Laboratory, is working on a noninvasive way to measure blood glucose levels. The technique uses Raman spectroscopy, first envisioned by Michael Feld (the late MIT professor of physics and former director of the Spectroscopy Laboratory). This method identifies chemical compounds based on the frequency of vibrations of the bonds holding the molecule together. Specifically in this case, the technique can reveal glucose levels by simply scanning a patient’s arm or finger with near-infrared light, eliminating the need to draw blood.

Ishan Barman and Chae-Ryon Kong from the Spectroscopy Laboratory are developing a small Raman spectroscopy machine; its size is similar to a laptop computer, and it could be used in a doctor’s office or a patient’s home. Estimations are that in the U.S. alone there about one million people in with type 1 diabetes – and many more worldwide; therefore the potential for the new device is huge.

The development of this technology is a long lasting process; various researchers in the Spectroscopy Lab worked on it for more than 15 years. One of the major obstacles they faced is near-infrared light’s limits; it penetrates only about half a millimeter below the skin, so it measures the amount of glucose in the fluid that bathes skin cells (known as interstitial fluid), not the amount in the blood. To overcome this, the team tried to predict blood glucose levels from the glucose concentration in interstitial fluid. This prediction relies on a sophisticated calibration algorithm that relates the two concentrations.

This calibration algorithm becomes more difficult immediately after the patient eats or drinks something sugary, because blood glucose soars rapidly – and the interstitial fluid glucose levels are still low (it takes between 5 and 10 minutes to see the corresponding surge). As a result, interstitial fluid measurements do not give an accurate picture of what is happening in the bloodstream.

This problem was solved using a new calibration method called Dynamic Concentration Correction (DCC). Barman and Kong developed the DCC technique to incorporate the rate at which glucose diffuses from the blood into the interstitial fluid. In a study of 10 healthy volunteers, they used DCC-calibrated Raman spectroscopy to significantly boost the accuracy of blood glucose measurements. The results, published in the journal Analytical Chemistry, show an average improvement of 15 percent; furthermore, some patients even had 30 percent improvement.

“Getting optical glucose measurements of any sort is something people have been trying to do since the 1980s,” says Michael Morris, professor of chemistry at the University of Michigan. He claims that the group appears to have solved a problem that has long stymied researchers. “Usually people report that they can get good measurements one day, but not the next, or that it only works for a few people. They can’t develop a universal calibration system.”

The noninvasive nature of Raman spectroscopy could help boost quality of life for diabetes patients, but the device has to be practical, affordable, and easy to use. While the project is yet to be completed, the team believes that the smaller machine they are now developing should substantially drive down costs by miniaturizing and reducing the complexity of the instrument.

TFOT has also covered the type 1 diabetes nanoparticle vaccine, researched at the University of Calgary in Canada, and the development of saliva test to catch early diabetes, made by scientists from Oregon and Indiana.

For more information about MIT’s device that will help measure blood glucose levels, see the official press release.

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