Towards a smartphone-aided electronic ELISA for real-time electrochemical monitoring

This paper details the design and fabrication of a portable, smartphone-integrated electronic platform, tailored to read-out electronic ELISA (eELISA) data from printed circuit board (PCB)-based sensors. The instrument features eight independent, re-configurable current input channels, each consisting of a low-noise transimpedance amplifier (TIA) and filtering stage coupled to low-noise switch ICs for automatic current range detection. A bipolar, 16-bit resolution voltage-input analog-to-digital converter (ADC) has been employed for digitisation of converted current values received from the analogue front-end. In addition, a bipolar, 12-bit resolution digital-to-analog converter (DAC) combined with standard three-electrode potentiostats provides wide range biasing voltages to the amperometric sensors. The resulting digital data is transmitted via serial interface to an Android-based smartphone, where an ergonomic user interface guides the operator through the detection process. The customised Android application (App) provides real-time monitoring of the electrochemical cell and stores returned biochemical data on the device once measurement is complete.