Integrated Sensing System on Flexible-based Extended-gate Organic Field-effect Transistor for Electroanalytical Applications of DA/AA/UA

Organic field-effect transistors (OFETs) represent a breakthrough biosensing technology owing to their exceptional sensitivity, mechanical flexibility, and cost-effective manufacturing. The simultaneous detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA) holds critical importance in clinical diagnostics as these biomarkers provide vital information about neurological health, antioxidant status, and renal function. Conventional detection methods face significant challenges due to the overlapping oxidation potentials of these molecules in electrochemical measurements, resulting in poor selectivity and accuracy. Developing advanced sensing platforms capable of discriminating these biomarkers in complex biological samples remains an urgent requirement in modern healthcare diagnostics. This research successfully developed a molecularly engineered extended-gate OFET biosensor for simultaneous detection of DA, AA, and UA with exceptional performance. The functionalized sensing interface, incorporating cysteamine for DA recognition, carboxylated graphene oxide for AA catalysis, and p-AMTa for UA binding, achieved remarkable detection limits of 0.28 μM, 0.35 μM, and 0.41 μM respectively. Comprehensive cross-reactivity studies demonstrated excellent specificity with interference below 5.2% in mixed analyte solutions. Quantitative validation using standard addition method showed recovery rates of 97.2-103.8% and relative errors consistently under 4.2%, confirming high detection accuracy. The biosensor maintained outstanding operational stability over 30 detection cycles with RSD < 5.1%, demonstrating excellent reproducibility. This integrated platform represents a significant advancement in multiplexed biomarker detection, offering a reliable approach for complex sample analysis. This work provides a robust strategy for simultaneous electrochemical detection of multiple biomarkers, effectively addressing selectivity challenges in conventional biosensing. The developed platform demonstrates strong potential for clinical diagnostics and point-of-care testing applications, enabling rapid disease screening and health monitoring. This technology represents a significant step forward in the development of high-performance, cost-effective diagnostic tools for healthcare applications.