Exploring the Efficacy and Suitability of Infrared Sensors at 940nm and 1150nm Wavelengths for Non-Invasive Glucose Monitoring: A Comparative Study

Abstract

The changing lifestyle has resulted in the rise of the high prevalence of diabetes globally. Patients diagnosed with diabetes need to constantly keep track of their sugar levels. This is widely used so that necessary action can be taken to correct insulin deviation. The current invasive and minimally invasive methods used are useful, but expensive and prone to pain and infections. As a remedy, non-invasive methods are preferred. Among non-invasive methods, is the use of NIR technique. This give promising results, pain-free, free from infections and the method is cheap. The study comparatively investigates 940nm and 1150nm IR sensors to determine and ascertain their efficacy and suitability for monitoring glucose. The study used 940nm LED, and 1150nm IR LED independently as transmitters, and two photodiodes each with spectral wavelength range from 900nm to 1700nm for sensing. The current-to-voltage amplifier, a filter, amplification, and linearization circuit were implemented using an LM358 op amp together with a combination of resistors and capacitors. Fifteen samples of glucose concentration were prepared for testing taking into account the same environmental conditionsIn both 940nm and 1150nm IR sensors, a change in glucose concentration give a voltage output. The water absorbance with the 1150nm sensor is high when compared with that of the 940nm sensor which is minimal. The efficacy of the two sensors as per Clarke Error Grid analysis are within the required ranges of region A and B, therefore suitable for
monitoring glucose non-invasively. The degree of accuracy as per Bland Altman is about 93% for the two sensors. The residual plots indicate appropriate regression lines for the two sensors. The Pearson correlation co-efficient shows a positive relation each with its own data. The 1150nm wavelength give good results it is apparent that 1150nm depicts higher sensitivity and high responsiveness to changes which is not depicted by 940nm