A flexible multiplexed electrochemical biosensing platform with graphene and gold nanoparticle modification for enhanced e-ELISA point-of-care biomarker detection

Rapidness, precision, affordability, and accessibility are central to point-of-care (POC) devices' great impact in the healthcare and medicine fields. Utilizing these devices in biomarker measurement and monitoring has improved early disease detection, prevention, and effective treatments. Among all detection strategies, electrochemical biosensors, with high selectivity, specificity, versatility, miniaturization potential, and portability, are vastly noticed and employed in POC detection. However, balancing accuracy, reliability, costeffectiveness, accessibility, and user-friendliness poses significant challenges in developing these devices. In this study, we propose a design and fabrication method fora flexible multiplexed electrochemical biosensor (FMEB) array. This device specifically aims to detect human blood biomarkers using electrochemical enzyme- linked immunosorbent assay (e-ELISA) technique. To enhance the sensitivity and detection capabilities of the present device, which uses readily available and accessible materials such as screen-printed carbon electrodes (SPCEs) on a flexible printed circuit board (FPC), surface modification methods using reduced graphene oxide (rGO) and gold nanoparticles (AuNPs) are employed. This combination results in a setup that achieves high accuracy, with a limit of detection (LOD) of 0.69 pg/ml within a wide linear assay range of 1-500 pg/ml. Two tested biomarkers, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), which play crucial roles in inflammation and immune response, were successfully detected in various concentrations. Extensive investigations conducted in this study suggest the potential of a reliable POC electrochemical biosensor that can integrate into lab-on-a-chip (LOC) platforms, potentially reducing healthcare costs and enhancing patient outcomes.