An Electrical parametric model of human skin and blood glucose spectroscopy

Abstract

Diabetes is well known as a leading cause of death all around the world. Mainly, invasive methods are used for blood glucose monitoring in the current context. The monitoring is done either as an inpatient procedures or using home based measuring devices. Invasive or minimally invasive methods make it di_cult when it comes to frequent measurements required by diabetes patients. It also has other issues such as the associated pain, phobia, and the spread of diseases like AIDS. These issues are heightened in the case of home based monitoring devices. As a result many researchers have attempted to introduce non-invasive measuring techniques for home based glucose monitoring devices. However none of then have met the accuracy requirements for medical use. Dielectric spectroscopy (DS) is one such methods which has been proposed for non-invasive glycaemia monitoring. In DS, the variation of skin impedance has been used to derive an index representing blood glucose uctuation. As a re- sult of the lack of knowledge of the impedance characteristics of the skin and the tissue underneath, and its relation to the level of blood glucose, the consistency and accuracy of the measurements are questionable. The ensuing research pro- poses a theoretical framework for skin impedance variations with the blood glucose level and also provides experimental veri_cation of the same. This research also proposes an electrical parametric (impedance) model for human skin and blood glucose spectroscopy which consists of human skin, electrode-electrolyte interface and coupling capacitance between transmitter and receiver. Such a mathematical model of the physiological system will enable us to further analyze the relationship the physiological parameters have with the uctuation of the blood glucose levels for di_erent individuals. Moreover, the thesis analyzes the inuence from bio-sensor to sensitivity mea- surements and proposes a concentric annular ring slot antenna (CARSA) as a possible sensor for non-invasive blood glucose measurement via DS. Compared to early research of Cada_ et al. [1], CARSA showed a 13 fold increment of the measurement sensitivity. Further, it could be seen that, this sensitivity increment was 40 fold when the e_ective length of CARSA decreases from 10 cm to 6.5 cm. The thesis further highlights the importance of careful design of this sensor and proposes a rigorous mathematical model of its derivation.