Transmission of Near-Infrared Light Through Varying Porcine Tissue Thicknesses Towards a Non-invasive Blood Glucose Sensor

Development of a non-invasive blood glucose monitor will enable higher compliance to blood glucose monitering with people living with diabetes. A reflectance based sensor utilising near-infrared spectrometry techniques and photoplythsmography signals has been developed. The sensor cannot reliably find a pulse in reflectance mode and the penetration depth of the wavelengths is unknown. Investigation in to the penetration depth of 1200, 1450, and 1550 nm light through porcine tissue was performed to determine the penetration depth and feasibility of development of the sensor in transmission mode. 660 nm light was also assessed for comparison as penetration depth this wavelength in human tissue is well documented.Eight tissue thicknesses and two tissue compositions were tested. The 1200 nm light achieved full transmission up to 6 mm thickness, and and predicted 50% transmission at 11.8 mm thickness. The 1450 nm achieved 99% transmission up to 2 mm thickness, and predicted 50% transmission at 5.5 mm thickness. The 1550 nm achieved full transmission at 1 mm thickness, and predicted 50% transmission at 4.5 mm thickness. The 1200 nm achieved higher transmission percentage than the 660 nm wavelength. The development of a NIR blood glucose sensor in transmission mode is feasible.