HELPStat: A Handheld, EIS-Enabled, Low-Cost, and Portable Potentiostat

Many potentiostat devices capable of Electrochemical Impedance Spectroscopy (EIS) have been developed to make this technique more affordable and portable for a wider variety of applications. However, current devices have limited frequency ranges that may not capture certain interactions of the electrochemical cell or are still limited to non-portable use cases. To address these limitations, we developed HELPStat, a handheld, low-cost, and standalone potentiostat capable of conducting EIS from 200 kHz to 0.15 Hz, complete with its own fitting algorithm, data storage, and Bluetooth Low-Energy (BLE) capabilities. HELPStat was tested with ideal Randles circuits and potassium ferricyanide, showing statistically comparable results to a benchtop potentiostat. We also demonstrated the capability to perform electrochemical measurements with a surface-bound cortisol aptamer, successfully differentiating responses between 1.5 ng/mL and 7 ng/mL of cortisol. With its open-source design, low-cost, modular, and portable platform, HELPStat can be adapted to user-specific requirements in wearable and point-of-care applications, enabling further advancements in making electrochemistry more accessible.