Noninvasive Blood-Glucose Monitoring to Replace Finger Pricks for Diabetics

These methods can be painful, inconvenient, and prone to skin irritation, leading many patients to test less frequently than recommended. Under-testing increases the risk of serious complications linked to poor glucose control. Researchers have now demonstrated a noninvasive way to measure blood glucose accurately using light, eliminating the need for needles or implanted sensors.

Researchers at the Massachusetts Institute of Technology (MIT, Cambridge, MA, USA) built a shoebox-sized device based on Raman spectroscopy, an optical technique that identifies chemical composition by analyzing how near-infrared light scatters within tissue. Instead of drawing blood or sampling interstitial fluid, the system shines light onto the skin and detects subtle glucose-specific signals mixed with background tissue signals. By redesigning the measurement approach, the device can assess glucose levels without breaking the skin or inserting any components into the body.

Earlier Raman-based systems required large, complex equipment because they analyzed the full Raman spectrum, which contains around 1,000 spectral bands. The MIT researchers simplified the process by identifying just three key bands needed for glucose detection—one glucose signal and two background references. This selective-band approach drastically reduced the size, cost, and complexity of the system, enabling glucose measurements with compact optical components while maintaining accuracy comparable to invasive monitoring technologies.

The device was evaluated in a clinical study at MIT’s Center for Clinical Translation Research. A healthy volunteer was monitored over four hours, with glucose readings taken every five minutes while the subject consumed two glucose drinks to induce changes in blood sugar. The findings, published in Analytical Chemistry, show that glucose measurements from the Raman-based device closely matched those from two commercially available continuous glucose monitors that rely on implanted sensors.

Although the initial prototype is not wearable, the researchers have already developed a smaller version, roughly the size of a smartphone, and are testing it in healthy and prediabetic volunteers. A larger clinical study involving people with diabetes is planned in collaboration with a local hospital. Future work focuses on shrinking the device further to a watch-sized format and ensuring accurate performance across different skin tones. If successful, the technology could enable comfortable, continuous glucose monitoring for a wide range of patients.

“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. Naturally, many diabetic patients are under-testing their blood glucose levels, which can cause serious complications,” said MIT research scientist Jeon Woong Kang, 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.”

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