NON-INVASIVE, CONTINUOUS, VASCULATURE-ANATOMY-INSPIRED RF-BASED SENSOR FOR GLYCEMIC MEASUREMENTS

Abstract

Diabetes is a chronic disease that affects more than 8.5% of the worldwide population. The glucometer, which is invasive, is the standard tool for monitoring glucose levels. This approach is painful and uncomfortable. Furthermore, it is not befitting to provide continuous glucose monitoring, often leading to missing some serious hyperglycemic and hypoglycemic events that could occur between finger-prick measurements. To overcome this problem, minimally invasive technologies have been developed. However, the frequent use of such techniques causes discomfort and pain in addition to high socio-economic burdens. Therefore, painless, needle-free, and continuous glucose monitoring sensors are needed to enhance the quality of life of millions of diabetic patients around the world. Today, holistic non-invasive approaches are not commercially available. Different approaches have been introduced in research such as: reverse iontophoresis, bioimpedance spectroscopy, infrared and ocular spectroscopy and ultrasound. Such technologies suffer from several difficulties. For instance, interstitial fluid glucose levels measurements carry a serious time-delay compared to the plasma glucose levels. Additionally, the stability, safety and portability of the underlying technologies constitute their main challenges. Nowadays, researchers are focusing on electromagnetism as a leading technology to achieve noninvasive and continuous glucose monitoring. Here, we propose a non-invasive continuous wearable glycemic monitoring electromagnetic based multi-sensor system with enhanced sensitivity. The system wirelessly senses hypo- to hyper-glycemic variations with very high accuracy. It leverages novel vasculature-anatomy-inspired electromagnetic front-end components. These components are designed to target simultaneously multiple body locations. Multiple environmental and physiological sensors are also integrated in the proposed system to calibrate out the perturbing factors. The system is validated on serum, animal tissues and in a clinical setting. Serum-based and ex-vivo experiments demonstrate high precision across the diabetic glucose range (10mg/dl - 600mg/dl). Human trials exhibit clinical accuracy of 98% in fifty five subjects who underwent around hundred Oral Glucose Tolerance Tests. The proposed sensors are embedded in a glove and a sock; results are validated on the sensors both standalone and collectively. The system captures the clinical glycemic variations without any time-lag, reporting up to 96% correlation between the system’s physical parameters and blood glucose levels. To our knowledge this is one of the rare studies to assess the sensitivity of the proposed sensors over a wide glycemic range (10mg/dl to 600 mg/dl), in different experimental setups and to calibrate out the multiple environmental and physiological factors.