Dual-Chronoamperometry Drift Correction for Electrochemical Sensors
Kimberly T. Riordan, Kefan Yang, Ethan Brazelton, Mohammed Eslami, Ashley Copenhaver, Fatemeh Esmaeili, Connor D. Flynn, Zhenwei Wu, Scott E. Isaacson, Dingran Chang, Maria D. Cabezas, Vuslat B. Juska, Jagotamoy Das, Edward H. Sargent, Shana O. Kelley
Abstract
Accurate sensing of biomolecular targets is crucial for diagnosing diseases and developing technologies for personalized medicine. However, measuring biomarker levels with high precision is often challenging due to signal drift caused by biofouling and monolayer instability. We demonstrate a novel continuous dual-chronoamperometry method with faradaic current extraction to enable accurate and reliable detection of biomarkers in the presence of drift. We apply two sequential chronoamperometry pulses, a reference (-500 mV) and a test (+500 mV), to capture all capacitive and faradaic currents in the range. In the absence of the target, the drift in the reference and test currents is multilinear, and this relationship can be used to predict the contribution of the target current. As a proof-of-concept, we demonstrate that signal drift can be corrected using our molecular pendulum for IFN-γ detection. Importantly, we show that this technique is broadly applicable to other amperometry-based systems such as a monolayer transporter sensor, an electrochemical DNA sensor, and electrochemical aptamer-based sensors. Moreover, we train a linear regression machine learning model and use its error to quantify target concentrations with dual-chronoamperometry data. This novel method enhances the reliability and sensitivity of chronoamperometry, paving the way for its application in real-time monitoring scenarios.