8. Comparative Analysis of Optoelectronic Properties of Glucose for Non-invasive Monitoring

Among the diversity of methods for glucose level monitoring in human blood, invasive techniques are still the most commonly used. Blood samples, usually obtained with finger-pricking devices, are analysed through enzymatic reactions via electrochemical or photometric principles. In this paper, non-invasive methods for blood glucose monitoring are studied and compared, while also analysing optical and electronic properties of glucose. From this comparative analysis, proposals are made towards the design and characterisation of novel devices capable of monitoring blood-glucose levels through optoelectronic non-invasive procedures. Alteration of electrical parameters of cellular membrane, such as electric permittivity and conductivity as a function of blood glucose concentration, are observed and compared to the responses to optical stimuli. The investigation is developed by establishing a correlation between the effects of diffusion and dispersion of light on the concentration and dispersity of blood particles, and the response of electrical parameters under different glucose concentrations. As a result of the analysis, recommendations are made for the most suitable parameters and instrumental methodology, in terms of feasibility, easiness and precision, for non-invasive monitoring of blood glucose levels.