• MIT researchers have devised a way to measure blood glucose levels by shining near-infrared light on the skin.

    Photo: Patrick Gillooly

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  • Using this Raman spectroscopy machine, MIT researchers can measure blood glucose levels.

    Photo: Patrick Gillooly

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  • Spectroscopy Lab graduate students Ishan Barman, left, and Chae-Ryon Kong, right, talk with lab Associate Director Ramachandra Rao Dasari, center.

    Photo: Patrick Gillooly

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Shining a light — literally — on diabetes

Device from MIT lab could help diabetic patients monitor their blood glucose levels without finger pricks.

People with type 1 diabetes must keep a careful eye on their blood glucose levels: Too much sugar can damage organs, while too little deprives the body of necessary fuel. Most patients must prick their fingers several times a day to draw blood for testing.

To minimize that pain and inconvenience, researchers at MIT’s Spectroscopy Laboratory are working on a noninvasive way to measure blood glucose levels using light.

First envisioned by Michael Feld, the late MIT professor of physics and former director of the Spectroscopy Laboratory, the technique uses Raman spectroscopy, a method that identifies chemical compounds based on the frequency of vibrations of the bonds holding the molecule together. 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.

Spectroscopy Lab graduate students Ishan Barman and Chae-Ryon Kong are developing a small Raman spectroscopy machine, about the size of a laptop computer, that could be used in a doctor’s office or a patient’s home. Such a device could one day help some of the nearly 1 million people in the United States, and millions more around the world, who suffer from type 1 diabetes.

Researchers in the Spectroscopy Lab have been developing this technology for about 15 years. One of the major obstacles they have faced is that near-infrared light 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 came up with an algorithm that relates the two concentrations, allowing them to predict blood glucose levels from the glucose concentration in interstitial fluid.

However, this calibration becomes more difficult immediately after the patient eats or drinks something sugary, because blood glucose soars rapidly, while it takes five to 10 minutes to see a corresponding surge in the interstitial fluid glucose levels. Therefore, interstitial fluid measurements do not give an accurate picture of what’s happening in the bloodstream.

To address that lag time, Barman and Kong developed a new calibration method, called Dynamic Concentration Correction (DCC), which incorporates the rate at which glucose diffuses from the blood into the interstitial fluid. In a study of 10 healthy volunteers, the researchers used DCC-calibrated Raman spectroscopy to significantly boost the accuracy of blood glucose measurements — an average improvement of 15 percent, and up to 30 percent in some subjects.

The researchers described the new calibration method and results in the July 15 issue of the journal Analytical Chemistry. In addition to Feld, Barman and Kong, authors include Ramachandra Rao Dasari, associate director of the Spectroscopy Lab, and former postdoctoral associate Gajendra Pratap Singh.

Michael Morris, professor of chemistry at the University of Michigan, says the group appears to have solved a problem that has long stymied researchers. “Getting optical glucose measurements of any sort is something people have been trying to do since the 1980s,” says Morris, who was not involved in this study. “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.”

Morris says the noninvasive nature of Raman spectroscopy could help boost quality of life for diabetes patients, but that to be practical, any device would need to become more affordable and very simple to use. The Spectroscopy Lab researchers believe that the smaller machine they are now developing should substantially drive down costs by miniaturizing and reducing the complexity of the instrument.

Barman and Kong plan to launch a clinical study to test the DCC algorithm in healthy volunteers this fall. Their work is funded by the National Institutes of Health and National Center for Research Resources.

In October, Barman will receive the Tomas A. Hirschfeld Award at the Federation of Analytical Chemistry and Spectroscopy Societies Conference, for his work on improving spectroscopy-based glucose measurements.

Topics: Diabetes, Health sciences and technology, Physics, Spectroscopy


Cant wait til this is available and affordable. I have had Diabetes 1 for 73 years and am thorougly sick of pocking my fingers. If I poke my arm I get a big red welt. Good luck in your research and development.
I'm 78 years old; have type 2 diabetes. Will this be available to type 2 patients? Best wishes in your work.
I'm willing to pay more than thousand bucks if I can escape from painful finger pricks through my whole life. Please make it as fast as possible.
Is posible make the measure into the eye? Because I think it is an easy way to find thin capilares with blood.
I am hoping to see it available for all diabetic people. It will help millions of people across the globe.
Agree with the eye idea. Why not? Or under the tongue? Or eye lid? Or, how about drinking something that binds glucose to enhance signal?
Seconding jarroyo's suggestion of probing the eye to bypass the skin. Or, since the probe seems to be be pressed up against the surface measured, why not the tongue, or inside of the cheek?
The eye thing could be difficult due to the sensitivity of the eye and this could have a bad effect if the eye is exposed to some degree of infrared. Good job well done
I hope you can use (((ears))) to measure since blood is closet as possible to outer skin.
Don't know if the interstitial algorithm will help that much. Continuous Glucose Monitors are measuring interstitial fluid and we're doing OK with those. Mind you if they can get the algorithm working, I wonder if it would help with CGMs. I heard Dr. H. Wolpert suggest that interstitial fluid may be more useful in some cases as it represents the effective blood glucose level in your brain.
A good idea and a good invention. We hope this technique will be practical as soon as possible.
As the diabetes educator here at MIT I know that all the folks I care for would be delighted to have this technology! How do we find out about the clinical trials so we can offer ourselves as study participants!
Don't worry about the size (it is not a joke), we can have a device as big as a refrigerator, in our house, office or schools. We can still use the other methods when we are outside. But the most of time we are in a one place, with a lot of place. Best regards, best luck.
This would be so incredibly helpful for so many people in the future. When do you anticipate making such a device available commercially?
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