Electrochemical Strip Sensor Based on a Silver Nanoparticle-Embedded Conducting Polymer for Sensitive In Vitro Detection of an Antiviral Drug

A straightforward and disposable electrochemical sensor was developed by the direct electrodeposition of silver nanoparticles (AgNPs) on a conducting polymer and an acid-functionalized carbon nanotube-modified screen-printed carbon electrode (f-CNT/SPCE) for the detection of the antiviral drug valganciclovir (VGC). A scaffold layer of the conducting polymer 2,6-diaminopyridine (p-DAP) was electrodeposited on an f-CNT/SPCE surface via a potentiodynamic polarization method. Later, homogeneous deposition of AgNPs was carried out on the polymer-modified scaffold layers. The electrode activities related to the concentration of the polymer substrate and the AgNP precursor were systematically optimized. The electrochemical oxidation of VGC by SPCE/f-CNT/p-DAP-AgNPs was investigated by square-wave voltammetry. The modified sensor exhibited an attractive electroanalytical performance toward VGC with high sensitivity (nanomolar range), selectivity (in the presence of uric acid and dopamine), reproducibility, and long-term storage stability. Potential real-world applications of the modified screen-printed sensor were demonstrated using artificial urine/serum and industrial water samples. The straightforward design and attractive analytical performance of the conductive polymer-embedded AgNP -modified screen-printed sensor suggest considerable promise for use of this sensor in the point-of-care screening of antiviral drugs. The sensor strip would also be useful in the screening of antiviral drugs in industrial (quality control) and environmental (industry effluents) applications.