Noninvasive Imaging: A Glucose Monitor's Future Without Finger Pricks
Imagine a world where managing diabetes becomes less painful and more convenient. A groundbreaking development from MIT might just make that a reality. Researchers have created a noninvasive method to measure blood glucose levels, potentially eliminating the need for daily finger pricks for diabetes patients.
The MIT team utilized Raman spectroscopy, a technique that identifies tissue's chemical composition by using near-infrared or visible light. They crafted a shoebox-sized device capable of measuring blood glucose levels without any needles. In a healthy volunteer test, the device's measurements were comparable to those from commercial continuous glucose monitoring sensors, which require a wire implanted under the skin.
While the current device is too large for wearable use, the team has since developed a wearable version, currently being tested in a small clinical study. Jeon Woong Kang, an MIT research scientist and study senior author, emphasizes the significance of this innovation. He states, '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.'
The study, led by MIT postdoc Arianna Bresci, was published in the journal Analytical Chemistry. Other contributors include Peter So, director of the MIT Laser Biomedical Research Center (LBRC) and a professor of biological engineering and mechanical engineering, and Youngkyu Kim and Miyeon Jue of Apollon Inc., a South Korean biotechnology company.
Noninvasive Glucose Measurement
Currently, most diabetes patients measure their blood glucose levels by drawing blood and using a glucometer. Some opt for wearable monitors with sensors inserted just under the skin. These sensors provide continuous glucose measurements from interstitial fluid but can cause skin irritation and need replacement every 10 to 15 days.
MIT's LBRC researchers have been exploring noninvasive sensors based on Raman spectroscopy to create more comfortable wearable glucose monitors. This spectroscopy technique reveals tissue or cell chemical composition by analyzing near-infrared light scattering or deflection as it encounters different molecules.
In 2010, LBRC researchers demonstrated the ability to indirectly calculate glucose levels based on Raman signals from interstitial fluid and a reference blood glucose measurement. However, this approach wasn't practical for a glucose monitor.
A recent breakthrough allowed the researchers to directly measure glucose Raman signals from the skin. The glucose signal, usually too small to discern from other tissue molecule signals, was filtered out by shining near-infrared light onto the skin at a different angle from which the Raman signal was collected.
The researchers achieved these measurements using equipment the size of a desktop printer. They've since worked on shrinking the device's footprint.
In their new study, they analyzed just three spectral bands corresponding to specific molecular features in the Raman spectrum, typically containing about 1,000 bands. This approach reduced equipment amount and cost, enabling a cost-effective, shoebox-sized device.
'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,' Bresci explains. 'With this new approach, we can change the components commonly used in Raman-based devices, and save space, time, and cost.'
Towards a Wearable Sensor
In a clinical study at MIT's Center for Clinical Translation Research (CCTR), the researchers used the new device to take readings from a healthy volunteer over four hours. A near-infrared beam shone through a small glass window onto the skin for the measurement.
Each measurement took over 30 seconds, and the researchers took a new reading every five minutes. The subject consumed two 75-gram glucose drinks, allowing the researchers to monitor significant blood glucose concentration changes. The Raman-based device showed accuracy levels similar to two commercially available, invasive glucose monitors worn by the subject.
Since completing that study, the researchers have developed a smaller prototype, about the size of a cellphone, currently being tested as a wearable monitor in healthy and prediabetic volunteers. Next year, they plan a larger study with a local hospital, including people with diabetes.
The researchers are also working on making the device even smaller, about the size of a watch, and exploring ways to ensure accurate readings from people with different skin tones. The research was funded by the National Institutes of Health, the Korean Technology and Information Promotion Agency for SMEs, and Apollon Inc.
