Portable 3D-printed electrochemiluminescence sensor for simultaneous glucose and lactate monitoring.

Fast and reliable monitoring of metabolic biomarkers, including glucose and lactate, is critical for chronic diseases, sepsis, and other scenarios involving physiological stress. However, most diagnostic options depend on multiple serial tests, require complicated testing apparatus, and are too expensive to be useful in the point-of-care arena. To address these limitations, we present a portable, low-cost, and 3D-printed (3DP) electrochemiluminescence (ECL) biosensor capable of simultaneously detecting glucose and lactate in a single step. The biosensor incorporates interdigitated electrodes (IDEs) within a bipolar electrode (BPE) electrochemical system to enhance electron transfer and signal amplification. Through careful optimization of voltage, luminol concentration, and pH, strong and reproducible ECL signals were achieved, with detection limits of 0.1 mM for glucose (linear range 0.1 mM to 5.0 mM) and 80 µM for lactate (linear range 0.1 mM to 4.0 mM). Real serum analysis yielded 95-102% recovery rates, validating the device's clinical relevance. Combining an inexpensive smartphone-based readout and fabricated with low-cost carbon and polylactic acid (PLA) filaments, this device offers a scalable and field-deployable approach to real-time, decentralized diagnostics. The proposed prototype fills a critical void between laboratory analysis and standard healthcare needs and promotes accessible and affordable metabolic monitoring for underserved populations.