An Electrochemical Biosensor Platform for Rapid Immunoanalysis of Physiological Fluids

Cytokines are multifunctional chemical messengers produced in response to stimuli for regulating the innate and adaptive immune systems. Rapid detection of cytokines in physiological fluids will enable precision management of diseases, such as dry eye, postoperative infections, graft versus host reactions in organ transplant, and cancer. In this study, we present a portable electrochemical biosensor with electrokinetic enhancement for rapid detection of interleukin-6 in conductive fluids, including phosphate buffered saline, contrived tears, and human blood plasma. The multiplex electrochemical biosensor incorporates self-assembled monolayers and an enzymatic amplification cycle to achieve sensitive and specific detection of cytokine biomarkers. We establish electrokinetic enhancement by Joule-heating induced temperature rise and electrothermal fluid motion on the sensor surface for enhancing molecular advection and reaction kinetics, which overcomes major limiting factors of point-of-care immunoanalysis systems. By investigating the thermal and electrochemical characteristics of the system, we optimize the assay time and the signal-to-noise ratio of the biosensor for rapid immunoanalysis of physiological fluids. With its effectiveness and outstanding performance, the electrokinetics enhanced electrochemical biosensor provides a versatile platform for rapid immunoanalysis valuable for precision disease diagnosis and monitoring.