Investigation of the Glucose Molar Absorptivity Concerning Sugar Concentration at the Wavelengths 1300 nm and 1550 nm for Developing a Non-invasive Blood Glucose Monitoring Device

Abstract

Diabetes is a common disease worldwide. Therefore, blood sugar monitoring is crucial for timely intervention and treatment. However, the standard invasive blood glucose test method is uncomfortable, painful, and at risk of infection. There are many research efforts for developing alternative non-invasive blood glucose measurement methods. However, the commercial non-invasive monitoring device is not popular and still in development. The optical technique for blood glucose monitoring is very potential and interesting. The light source with multi-wavelengths in a wide range from ultraviolet to infrared is used to develop an optical-based blood glucose monitoring device. The molar absorption coefficient is a crucial parameter that describes the optical absorbance with respect to wavelength. This work investigates the glucose molar absorptivity regarding sugar content at wavelengths 1300 nm and 1550 nm in order to design a non-invasive blood glucose monitoring system in the future by combining these wavelengths with others. A self-developing experimental apparatus studies the glucose detection potential at these two wavelengths. The obtained findings are compared and confirmed using a portable optical power meter from Thorlabs and an integrating sphere photodiode power sensor from S144C. Consequently, as the glucose concentration rises from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{0}$</tex> to 3000 mg/dL, the molar absorptivity increases using 1300 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$nm$</tex> and is almost unchanged using 1550 nm. The average molar absorption coefficient is 22.64 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$l.mol^{-1}.cm^{-1}$</tex> at 1300 nm and 18.55 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$l.mol^{-1}.cm^{-1}$</tex> at 1550 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$nm$</tex> while the sugar concentration varied in a range of 1500 - 3000 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$mg/dL$</tex> . This preliminary result may serve for developing an optical-based non-invasive blood glucose monitoring device