The Back-End Calibration Circuit for Reducing Hysteresis and Drift Effects of the Potentiometric RuO2 Dopamine Biosensor

Electrochemical biosensors often encounter inaccuracies and unreliability in measurements due to non-ideal effects such as drift and hysteresis. This study presents an innovative back-end calibration circuit specifically designed to mitigate hysteresis and drift effects in potentiometric ruthenium dioxide (RuO ₂ ) dopamine biosensors. The proposed calibration circuit combines analog circuitry with a microcontroller, employing gain-configured inverting amplifiers to individually correct hysteresis effects induced by both low and high dopamine concentrations. Furthermore, an inverse drift signal is applied to counteract overall drift effects, significantly improving the precision of dopamine measurements. The biosensor utilizes a radiofrequency sputtering system to deposit RuO ₂ as a sensing membrane. A sequential drop-casting process is employed to add functional layers. Atomic force microscopy is utilized to characterize the surface morphology of the RuO ₂ sensing membrane, confirming its uniform pattern and exceptional flatness. Reproducibility and repeatability experiments validate the stability and consistency of the fabricated RuO ₂ dopamine biosensor, underscoring its potential for practical applications in the diagnosis of neurological disorders.