Raman-based Noninvasive Continuous Glucose Monitoring (CGM)
ABSTRACT
The importance of monitoring blood glucose cannot be overemphasized considering the increasing population of diabetics worldwide and the associated costs. Noninvasive glucose monitoring has been a technology in high demand to provide people in need with pain-free, convenient, and continuous or as frequent measurements as necessary. Over the past decades, a variety of technologies have pursued this long quest. Among many, Raman spectroscopy has been recognized as a promising method.
Our Raman-based glucose monitoring instrument is composed of a NIR (=830nm) diode laser, a high-throughput imaging spectrograph, optical filters, and a sensitive photodetector. The measurement is obtained by focussing the laser on the ear skin using 250 mW of continuous wave laser fluence at an incidence angle of 60°, forming an elliptical beam of 1 mm × 2 mm. The oblique illumination of the skin surface supresses unwanted Rayleigh light and selectively enhances the interstitial fluid glucose signal. The Raman signal from the skin is collected by a custom-made optical fiber probe. During a recent swine glucose clamping study, a tissue interface was installed to a pig’s ear and a Dexcom G6 was installed to its belly. YSI and Accu-Chek measurements were performed on IV blood draw samples. All four measurements were performed every five minutes. Raman-based noninvasive glucose monitoring demonstrated successful prospective prediction with no laser-induced skin damage observed. MARD from Raman-based noninvasive glucose monitoring sensor was 8.8% in comparison with 9.0% from Dexcom G6 and 5.0% from Accu-Chek. The Clarke Error Grid Analysis confirms the high correlation with the YSI measurement with 96.6% (144 out of 149 measurements) in Zone A and all remaining measurements in Zone B.
Based on this strong preclinical data, we are currently developing a wearable noninvasive Raman-based glucose monitoring sensor in collaboration with Apollon. Located in Seoul and Boston, Apollon is revolutionizing diabetes care with needle-free continuous glucose monitoring, powered by cutting-edge Raman spectroscopy. Apollon’s MOGLU recently won the CES innovation award. In this presentation, we will introduce our ongoing efforts on building small but sensitive Raman systems and its applications to noninvasive glucose monitoring.
BIOGRAPHY
Dr. Jeon Woong Kang is a research scientist at Massachusetts Institute of Technology. His area of expertise is biomedical spectroscopy, quantitative phase imaging, nonlinear microscopy and optical sensors for medical applications.
He was trained as a physicist at Pohang University of Science and Technology (POSTECH). During graduate school, he studied interferometry, digital holography and developed several optical instruments for nondestructive (non-invasive) optical measurements. After PhD, He joined Wellman Center for Photomedicine in Massachusetts General Hospital as a research fellow where he developed a novel scanning method based on wavelength manipulation of Ti: Sapphire laser. This technique enables one-dimensional beam scanning at the tip of two photon microendoscope without mechanically moving component.
After two years’ experience in MGH, he moved to MIT Laser Biomedical Research Center. With Drs. Michael Feld, Ramachandra Dasari and Peter So, he significantly expanded his skills to biomedical spectroscopy. In 2013, he was promoted to a research scientist. Since then, he has taken care of overall biomedical spectroscopy activities in the center and is also involved in commercialization of biomedical spectroscopy techniques. His research topics include Raman-based CGM, spectroscopy-guided cancer biopsy, intra-operative cancer margin assessment, intra-needle optical sensor for medical needle guidance, label-free identification of cellular senescence and so on.