Non-Invasive Glucose Measurement Using Raman Spectroscopy During Oral Glucose Tolerance Test

Diabetes mellitus (DM), caused by impairment in the glucose metabolism is a worldwide epidemic. It is projected that by the year 2035 there will be approximately 592 million diabetic patients. Blood glucose (BG) levels are finely regulated by insulin secretion and any defects in the secretion or function can lead to DM. As no well-established medical intervention for DM has been known till date, continuous monitoring of BG is the only way to avoid secondary metabolic complications such as strokes, heart attacks, high blood pressure, blindness and coma. Diagnosis and therapeutic monitoring of diabetes requires direct measurement of plasma (or blood) glucose. Measurement of the fasting glucose level is the preferred test for diagnosis of diabetes in children and non-pregnant adults, while the oral glucose tolerance test (OGTT) is the preferred method of diagnosis for gestational diabetes. In addition, patients with an established diagnosis of insulin-dependent diabetes (all type-I and many type-II) require frequent glucose measurements for therapeutic monitoring. Emergence of hand-held glucose sensors have enabled patients with the ability to self-monitor the BG level. The frequent monitoring requires small blood sample (<1 µL) obtained by a "finger-pricking" and electrochemical sensing using a portable 'glucometer'. However the procedure is inconvenient, results in poor patient compliance and lacks in providing real time information about concentration changes. Regardless of the clinical test performed, withdrawal of blood or interstitial fluid is currently required for measurement of BG levels.

The proposed study is based on preliminary research supported by the MIT Laser Biomedical Research Center (LBRC), and promising results obtained with spectroscopic measurement of blood glucose in the laboratory, in an experimental animal model, and in a small cohort of human subject volunteers. In order to make non-invasive glucose measurement a viable clinical technology, however, a methodological implementation and validation from bench to bedside is required. In the application, we propose to accomplish this goal by means of a carefully-designed translational research study employing specifically-designed instrumentation and methods for pre-clinical validation and early clinical studies in human subjects. These studies will incrementally increase in data complexity, culminating in a clinical study in human subjects, as well as a non-invasive, spectroscopic glucose tolerance test as an alternative to OGTT.