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. According to MIT, 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 U.S., and millions more around the world, who suffer from Type 1 diabetes, MIT noted.
In an e-mail response to Medical Device Daily’s questions, Barman and Kong said that the potential for offering diabetes patients – in particular Type I patients who often require several finger-prick tests a day – a non-invasive measurement of blood glucose levels is what inspired this research. “Such a probe could also be used as part of an ‘artificial pancreas’ package in conjunction with insulin pumps,” they said.
Researchers in the MIT 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.
Barman and Kong have been involved with this research for the better part of three years. They told MDD that they initiated a correction for the calibration problem a couple years ago. They 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 team used DCC-calibrated Raman spectroscopy to significantly boost the accuracy of blood glucose measurements – an average improvement of 15%, and up to 30% in some subjects.
“In conjunction with this correction,we are now in the process of developing a miniaturized instrument and building a functional prototype in the next year,” the grad students told MDD.
They 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.
Barman and Kong plan to launch a clinical study to test the DCC algorithm in healthy volunteers this fall. The researchers are receiving funding from the National Institutes of Health and National Center for Research Resources.
The researchers hope their device will make it less painful and more convenient for diabetes patients to check their blood glucose level.
“As is well-known, disorders of glucose homeostasis, including Types 1 and 2 diabetes, as well as gestational diabetes, represent a leading cause of morbidity and mortality worldwide. Given the lack of a comprehensive cure, the optimal way to increase longevity and quality of life is by proper monitoring of glycemic control. Typically, such glucose measurements are performed by blood withdrawal (finger-prick testing),” Barman and Kong said. “Clearly, this is painful and hugely inconvenient, e.g. Type I diabetics may need [up to 10] such measurements a day.”
Source : Amanda Pedersen