A groundbreaking noninvasive method for measuring blood glucose levels, developed at the Massachusetts Institute of Technology (MIT), promises to save diabetes patients from the frequent discomfort of finger pricks. The innovative approach utilizes Raman spectroscopy, a technique that reveals the chemical composition of tissues by shining near-infrared or visible light on them, to measure blood glucose levels without the need for needles.
The MIT team has successfully developed a shoebox-sized device that, in tests with a healthy volunteer, produced measurements comparable to those obtained by commercial continuous glucose monitoring sensors, which require a wire to be implanted under the skin. Although the current device is too large to be worn, researchers have since created a wearable version that is undergoing testing in a small clinical study.
Advancements in Noninvasive Glucose Monitoring
Traditionally, diabetes patients have relied on finger pricks to measure blood glucose levels using a glucometer. Some have adopted continuous glucose monitors, which involve a sensor inserted just under the skin. While effective, these sensors can cause skin irritation and require regular replacement every 10 to 15 days.
In pursuit of a more comfortable alternative, researchers at MIT’s Laser Biomedical Research Center (LBRC) have been exploring noninvasive sensors based on Raman spectroscopy. This technique analyzes how near-infrared light is scattered by different molecules, revealing the chemical composition of tissues or cells.
Back in 2010, the LBRC team demonstrated that they could indirectly calculate glucose levels by comparing Raman signals from the interstitial fluid with reference blood glucose measurements. Although reliable, this method was not practical for a consumer glucose monitor. Recent breakthroughs have allowed researchers to directly measure glucose Raman signals from the skin, overcoming challenges of signal interference from other molecules.
From Laboratory to Wearable Technology
In their latest study, the MIT researchers developed a smaller device by focusing on just three spectral bands in the Raman spectrum, which correspond to specific molecular features. This approach significantly reduced the size and cost of the equipment, making it feasible to create a device about the size of a shoebox.
“By refraining from acquiring the whole spectrum, which has a lot of redundant information, we go down to three bands selected from about 1,000,” explained Arianna Bresci, the lead author of the study published in the journal Analytical Chemistry. “With this new approach, we can change the components commonly used in Raman-based devices, and save space, time, and cost.”
Clinical Testing and Future Prospects
During a clinical study at the MIT Center for Clinical Translation Research (CCTR), the new device was used to take readings from a healthy volunteer over four hours. As the subject rested their arm on the device, a near-infrared beam measured blood glucose levels through a small glass window on the skin. Each reading took just over 30 seconds, with new measurements every five minutes.
Throughout the study, the subject consumed glucose drinks, allowing researchers to monitor significant changes in blood glucose concentration. The Raman-based device demonstrated accuracy levels comparable to two commercially available invasive glucose monitors.
Following this success, the researchers have developed a smaller prototype, roughly the size of a cellphone, which is currently being tested as a wearable monitor in healthy and prediabetic volunteers. Plans are underway for a larger study next year, involving people with diabetes at a local hospital.
Broader Implications and Challenges
The implications of this technology are far-reaching. “For a long time, the finger stick has been the standard method for measuring blood sugar, but nobody wants to prick their finger every day, multiple times a day,” said Jeon Woong Kang, an MIT research scientist and senior author of the study. “If we can make a noninvasive glucose monitor with high accuracy, then almost everyone with diabetes will benefit from this new technology.”
The team is also working on further miniaturizing the device to the size of a watch and ensuring it provides accurate readings across different skin tones. This research was supported by the National Institutes of Health, the Korean Technology and Information Promotion Agency for SMEs, and Apollon Inc.
The development of this noninvasive glucose monitoring technology marks a significant step forward in diabetes management, potentially improving the quality of life for millions of patients worldwide.
