A Potentiometric Uric Acid Biosensor Integrated With Temperature Correction Readout Circuit on Flexible PCB

This study presents the enzymatic potentiometric uric acid (UA) sensor with a temperature correction circuit, sensor set readout, and integration on a flexible printed circuit board (FPCB). Coupled with the UA sensor calibrated by the temperature sensor, the readout voltage can respond directly to the sensed UA value. Complete circuits are surface mounted on commercial electroless nickel immersion gold (ENIG) FPCBs. Such a miniaturized potentiometric sensor provides the shortest signal path to reduce measurement errors and noise interference. The voltage–time measurement system used to measure the sensing characteristics of the potentiometric UA sensor is also analyzed. In addition to high linearity and repeatability, the sensor has an average sensitivity of 19.65 mV/(mg/dL), and the error caused by temperature changes is reduced by 81% after temperature correction.