Thread based wearable electrochemical sensor for uric acid detection

Abstract

Novel cotton thread-based electrochemical sensor was successfully fabricated for a non-invasive and non-enzymatic detection of uric acid (UA), a biomarker of gout disease. In this work, the working electrode was prepared by coating a carbon ink on the cotton thread to create the conductive property, followed by electrode modification using gold nanoparticles (AuNPs) to increase electrode surface area and conductivity. The morphologies of the modified electrode were characterized by scanning electron microscopy (SEM) with energy dispersive X-rays spectroscopy (EDX), confirming that AuNPs were modified on the electrode surface and the surface area of the modified electrode increased. The electrochemical characteristics were also studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), indicating that the modified electrode provided approximately 2 times higher electrochemical signals than an unmodified electrode. Under the optimal conditions, the modified cotton thread-based sensor exhibited the detection of UA with a linear range of 0.01-5.0 mM and a limit of detection (LOD) of 0.12 μM. Moreover, the modified sensor was investigated to be interferent free from common interfering substances and could be stored for 30 days without efficiency loss. Ultimately, this modified cotton thread-based sensor was effectively applied for the determination of UA in human urine sample and the obtained results were validated by comparing with mass spectrometry as a standard method.