A thread-based micro device for continuous electrochemical detection of saliva urea

Urea concentration is an essential indicator of various kidney diseases. The development of an effective method for detecting urea is still an important task. In recent years, microfluidic devices have become an attractive approach for constructing a novel urea analysis system because of their advantages such as less reagent and low sample consumption and high analysis speed. In this report, a cotton thread-based microfluidic electrochemical analysis device was developed for flow urea detection by 3D printing technology. Cotton thread was used as the microfluidic channel for sample flow and NiS/GO modified carbon paste electrode was worked as a urea sensor. The experimental results showed that the proposed microfluidic device provided a stable carrier fluid flow rate and a significant catalytic performance for the electrochemical oxidation of urea. The device allowed to detect urea in the concentration range from 0.1 mM to 6.0 mM with a detection sensitivity of 32.61 & mu;A L mmol-1. In addition, the proposed method has been successfully applied to the detection of urea in human saliva samples by a non-enzymatic amperometry method. More importantly, the approach can be successfully applied to nonenzymatic amperometric detection of urea in human saliva samples.