A miniaturized electrochemical device based on the nitrogen, carbon-codoped bimetal for real-time monitoring of acetaminophen and dopamine in urine

In-situ real-time detection of drug metabolites and biomolecules in hospitalized patients' urine helps the doctors to monitor their physiological indicators and regulate the use of drug doses. In this work, nitrogen-doped carbon-supported bimetal was prepared into the screen-printed electrodes (SPEs) and applied for real-time monitoring of acetaminophen (AC) and dopamine (DA) in urine. Via one-step pyrolysis of the core-shell cubic precursor (Cu3[Co(CN)6]2@Co3[Co(CN)6]2, CuCo@CoCo), the nitrogen-doped carbon-supported bimetal (CuCo-NC) was formed. The bimetal composites presented twice higher catalytic activity than the counterparts with single metal. In addition, the nanocomposites exhibited strong conductivity after pyrolysis, promoting electron transport efficiency as indicated by impedance measurements. Accordingly, the CuCo-NC based sensor offered excellent sensitivity with the detection limits down to 50 nM and 30 nM at the detection range of 0.1-400 μM and 0.2-200 μM for detection of AC and DA, respectively. Finally, in combination with a miniaturized electrochemical device, the sensor was applied for in-situ real-time monitoring of AC and DA in the urinary bag for up to 12h. As compared with other techniques such as high-performance liquid chromatography, UV-spectrophotometry and fluorescence spectrometer, the biosensor demonstrated the advantages of real-time monitoring, easy operation and excellent portability. However, the multi-component detection and self-calibration function need to be further developed. This method paves a way for the continuous monitoring of drug metabolites and biomolecules of hospitalized patients.