Co Single-Atom Nanozymes for the Simultaneous Electrochemical Detection of Uric Acid and Dopamine in Biofluids

Abstract

The development of enzyme-like electrochemical sensors with atomic-level catalytic activity sites is essential for the accurate and sensitive detection of active molecules in biological fluids. In this study, a sensitive signal amplification platform for simultaneous analysis of dopamine (DA) and uric acid (UA) was prepared on a screen-printed carbon electrode (SPCE). The sensing platform combines polypyrrole (Ppy) with high electrical conductivity and cobalt single-atom nanozymes of tubular bisparaben nitrogen-carbon (Co-NNC) with excellent strong oxidase activity, named Ppy-Co-NNC/SPCE. The single-atom catalytic process and detection mechanism were investigated by using density functional theory. DA and UA were simultaneously detected in the ranges of 1−50 and 2−500 μM with detection limits as low as 0.025 and 0.411 μM, respectively. In addition, real-time detection of uric acid in sweat under resting and exercising conditions was achieved using a poly(vinyl alcohol) hydrogel as a sweat collector in combination with Ppy-Co-NNC/SPCE. Moreover, the simultaneous detection of UA and DA in human urine was also achieved. The method provides a new strategy for the detection of small molecules in biofluids, which is promising for sensing and personalized medicine.

A Dopamine Detection Sensor Based on Au-Decorated NiS2 and Its Medical Application

“…The slope of this regression curve indicates that this electrochemical behavior is mainly controlled by diffusion, and its reversibility is good [ 40 , 41 , 42 ]. In the oxidation reaction, DA is converted to DA quinone, which is then reduced back to DA in the electrochemical reaction [ 43 ].…”

“…Cyclic voltammetry was performed within the voltage range of −0.2 V to 0.6 V at the same scan rate (0.1 V s −1 ) to test the response signal to the addition of different concentrations of DA, as shown in Figure 5a. The linear regression equations obtained from cyclic voltammetry are as follows: The slope of this regression curve indicates that this electrochemical behavior is mainly controlled by diffusion, and its reversibility is good [40][41][42]. In the oxidation reaction, DA is converted to DA quinone, which is then reduced back to DA in the electrochemical reaction [43].…”

Electrochemical Sensor for the Detection and Accurate Early Diagnosis of Ovarian Cancer

“…The LOD was determined according to the International Union of Pure and Applied Chemistry (IUPAC) guidelines L O D = 3 σ / b where b is the slope of the standard curve and σ represents the standard deviation of blank measurements (in the absence of any analyte; n = 3).…”