Miniaturized Optical Glucose Sensor Using 1600-1700 nm Near-Infrared Light

Blood glucose measurement is crucial for diabetes diagnosis and treatment, but invasive sampling methods have drawbacks. Non-invasive near-infrared (NIR) spectroscopy-based optical glucose sensing has gained attention but faces challenges due to the strong absorbance of NIR light by water and the need for complex equipment. Here, four distinct glucose fingerprints at specific NIR wavelengths: 1605, 1706, 2145, and 2275 nm are identified. Utilizing a surface-mounted LED with a spectral range of 1600-1700 nm and focusing on the most prominent peaks at 1605 and 1706 nm, a miniaturized and non-invasive glucose sensor is developed. The device successfully detects in vitro assays of glucose solutions within the physiological range of 50-400 mg dL-1, attaining a limit of detection as low as 10 mg dL-1. The findings demonstrate the feasibility of NIR spectroscopy-based glucose sensing and its potential applications in non-invasive point-of-care diagnostics, with the potential for extension to other biomarkers in future.