A miniature potentiostat for integration with wearable biosensors toward rapid and continuous monitoring of disease biomarkers

Monitoring the levels of disease biomarkers in human body fluids (e.g. blood, sweat, saliva) using an electrochemical biosensor usually entails a potentiostat to control and run the electroanalytical experiments. However, the commercially available potentiostats are bulky, expensive, and not suitable for wearable applications. This study aims to design a low-cost potentiostat circuit that can operate in a wearable configuration and read data from a multi-electrode electrochemical biosensor. The digital module of the potentiostat consists of the ESP32-S2 microcontroller whereas the analog module is a series of operational amplifiers. Together the two modules extract concentrations of the biomarkers using a previously obtained calibration curve. Our simulation results demonstrate that the potentiostat can apply and measure potentials in the range of ± 0.8 V and measure and apply currents ranging up to 200 μA. This miniaturized potentiostat will be able to perform cyclic voltammetry, amperometry, and Electrochemical Impedance Spectroscopy based measurements. Our prototype has an estimated size of 4.85 × 3.9 cm2 (fits inside a wristband) and an overall cost of $22.47, which are lower than the currently available potentiostats on the market. The results obtained from this portable potentiostat will be compared with a commercially available potentiostat to validate its accuracy. We will integrate this potentiostat with our previously designed four-electrode wearable biosensor that will assist in continuous and rapid monitoring of prokaryotic infections in human sweat. The societal benefits of this research are significant because the potentiostat when combined with a wearable biosensor has the potential for early diagnosis and intervention through on-body data analytics.