Wireless Biosensing System for Daily Self-Testing of Salivary Uric Acid

Abstract

Here, we report an electrochemical biosensing system capable of performing daily self-testing of uric acid (UA) using saliva. With the aim of daily use, we employed a simplified paper-based sampling device that allows users to collect saliva by themselves, and an amperometric biosensor for the rapid determination of salivary uric acid (SUA) contained in the sampling device without any pretreatment. To utilize the biosensor on site, a wireless control unit with an on-chip potentiostat and Zigbee wireless module was developed. The fundamental characteristics of the biosensor were first evaluated using amperometric techniques. A linear relationship between the concentrations of UA and output currents was confirmed to range from 10 µM to 400 µM. As a real sample test, the biosensor was applied to the measurement of SUA levels in seven healthy male volunteers. The estimated SUA levels were similar to those measured using a commercial UA test kit. Changes in the SUA levels after exercise were also tested. The SUA levels in all the volunteers increased after a bicycle exercise (140 bpm, 10 min). This result was consistent with those obtained in previous studies. Based on the obtained results, our sensor is expected to be useful in the daily self-testing of SUA to improve public health.