This Small Business Innovation Research Program Phase I project proposes to develop a handheld Raman optical system for monitoring blood glucose levels noninvasively, continuously, and in real-time. Raman spectroscopy uses laser light scattered by chemical species to distinguish, identify, and quantify them based on the shifted spectrum found in their optical fingerprint. The fingerprint of glucose can be used to key in and register its changes in concentration over time in biological tissues, such as in the interstitial fluid and in the blood. The objectives of this project are to miniaturize an existing Raman bench-top system to one that is wearable, low-cost, and optimized for blood glucose measurement in diabetic patients. Because this approach is noninvasive, it has the potential to limit the multiple-daily finger prick measurements required to draw blood for glucose measurement, and obviates biofouling issues associated with existing commercial continuous glucose monitors that require catheter inserts. Because it can measure continuously, measurements can provide curve data instead of static single-shot measurements from each finger prick. Glucose dynamics obtained from this data can then be used to establish a better regimen for glucose control with a combination of better diets and improved insulin dosage.
The broader impact/commercial potential of this project is to help improve the lives of 26 million American diabetics where blood glucose control is central to their health. The Center for Disease Control (CDC) predicts one out three Americans (almost 150 million) will be diabetic by 2050. The American Diabetes Association (ADA) and CDC also estimate the existing cost in the United States of diabetes, direct and indirect, to be $108B ~ $174B annually. These costs can be significantly mitigated with better management of care, where accessibility and adoption of newer, cost-effective, easy-to-integrate, and easy-to-use technologies can reduce direct costs, and where preventative warnings could reduce indirect costs. If this program's miniaturization thrust succeeds, there are multiple blood analytes that a handheld platform could address, including ketones, lactates, urea, cholesterol, hematocrit, and alcohol. As an example, law enforcement could use it in the field to detect illegal substances in the bloodstream. Miniaturization also enables mobile self-diagnostics and patient compliance, two enormous emerging markets. The ability to relay diagnostic data to clinicians remotely and in real-time for analysis to portend medical emergencies would be revolutionary.
We have developed a free-space optical technique that uniquely reduces parasitic Rayleigh scatter to collect photons emitted by Raman scattering from a point of interest within multilayered geometry such as human skin. Such a technique can be applied to making transcutaneous glucose measurements in the interstitial fluid and in the blood, thereby enabling a noninvasive approach to measuring blood sugar levels for diabetics. Furthermore, conventional bloodstick readings are single snapshot data points; this has the potential to provide trending glucose data pre- and post-pardial and to provide it continuously. This has tremendous implications for clinicians to apply customized remedies for blood sugar control that are tailored and individual-specific. This free-space technique has been uniquely reduced to optical components that are miniaturized on a silicon platform to develop a wearable biometric sensor. We employ strategies to reduce assembly cost and optical component cost without sacrificing significantly in performance and at the same time reducing our bill of materials. While there are many aspect to reducing the risk associated with a miniaturized wearable glucose sensor, the development of a better collection mechanism and the ability to miniaturize are two critical ones. Our next steps will be to show that such a technique can be successfully taken off the lab bench and from a feasibility stage, and employed on humans.
