Potentiostats for protein biosensing: Design considerations and analysis on measurement characteristics

The demand for the development of swift, simple, and ultrasensitive biosensors has been increasing after the introduction of innovative approaches such as bioelectronics, nanotechnology, and electrochemistry. The possibility to correlate changes in electrical parameters with the concentration of protein biomarkers in biological samples is appealing to improve sensitivity, reliability, and repeatability of the biochemical assays currently available for protein investigation. Potentiostats are the required instruments to ensure the proper cell conditioning and signal processing in accurate electrochemical biosensing applications. In this light, this review is aimed at analyzing design considerations, electrical specifications, and measurement characteristics of potentiostats, specifically customized for protein detection. This review demonstrates how a proper potentiostat for protein quantification should be able to supply voltages in a range between few mV to few V, with high resolution in terms of readable current (in the order of 100 pA). To ensure a reliable quantification of clinically relevant protein concentrations (>1 ng/mL), the accuracy of the measurement (<1%) is significant and it can be ensured with proper digital-to-analog (10-16 bits) and analog-to-digital (10-24 bits) converters. Furthermore, the miniaturisation of electrochemical systems represents a key step toward portable, real-time, and fast point-of-care applications. This review is meant to serve as a guide for the design of customized potentiostats capable of a more proper and enhanced conditioning of electrochemical biosensors for protein detection