Optoacousto-fluidics Based Optical Rotation Measure for Blood Glucose Sensing

Significance: Glucose sensing in deep tissue is challenging due to high light scattering and the optical properties of tissue constituents. Objective: We present a novel approach that integrates polarized light with optoacousto-fluidics based glucose sensing. Methods: 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. Results: 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. Conclusion: 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).