A Low-Cost Paper-Based Microfluidic POCT Device for In Vitro Glucose Sensing Using Near-Infrared Detection

This study presents a low-cost Near Infrared (NIR)-based optical microfluidic POCT device for in vitro glucose detection on a paper-based microfluidic platform. The device is made using a UV-curable resin that has been widely used in the publishing industry, which is proposed as a low-cost alternative to the expensive SU-8 photoresist normally used in photolithography. A 940 nm NIR LED–photodiode system was incorporated to non-invasively measure glucose levels. Glucose concentrations ranging from 62.5 to 1000 mg/dL were tested using only 3 µL of sample. To evaluate the effect of light intensity, three different LED currents (0.5, 0.75 and 1 mA) were applied. Output voltage ranged from approximately 570 to 700 mV and decreased with increasing glucose concentration, following Beer-Lambert's law. Regression models yielded R² values above 97%, confirming the device's accuracy and its potential for real-time, disposable, paper-based microfluidic glucose monitoring in point-of-care settings.