Optoacousto-Fluidics Based Optical Rotation Measure for Blood Glucose Sensing.

Abstract

Glucose sensing in deep tissue is challenging due to high light scattering and the optical properties of tissue constituents. We present a novel approach that integrates polarized light with optoacousto-fluidics based glucose sensing. A custom microfluidic chip mimicking blood vessel dimensions was developed to measure optical rotation via optoacoustic detection using polarized light (vertical and circular) at 1560 nm (near-infrared). The system reduces sample volume requirements while maintaining high sensitivity and accuracy. Experiments were performed using serum-like and human blood samples at a depth of 2 mm through whole blood. Flow dynamics was varied to assess their impact on measurement accuracy. Proof-of-concept studies included samples from diabetic and healthy volunteers. Depth-resolved optoacoustic signals enabled accurate optical rotation quantification for glucose detection. Variations in flow velocity showed no significant effect, confirming system reliability under dynamic conditions. The system achieved a detection limit of 50 mg/dL in serum samples. Classification of diabetic and healthy samples reached an 88% prediction accuracy. This work demonstrates a low-volume, high-sensitivity method for glucose detection using polarized light and optoacousto-fluidics, with potential for real-time, non-invasive monitoring at tissue depths of 2-3 mm. It lays the foundation for advancing optical rotation-based glucose detection methodologies with significant implications for in-vivo sensing (at depths of 2-3 mm in skin).