Sensitive and specific detection of influenza virus A/H3N2: An electrochemical aptasensor modified with AuNPs-PEI-MWCNTs.

This study developed a sensitive and specific electrochemical aptasensor for the urgent, on-site detection of Influenza A/H3N2 virus. The aptasensor utilizes an AuNPs-PEI-MWCNTs nanocomposite deposited on a glassy carbon electrode (GCE), with a DNA aptamer targeting the influenza H3N2 hemagglutinin (HA) antigen covalently linked via thiol-gold chemistry. Virus quantification was achieved by incubating the modified electrode with H3N2 and measuring the differential pulse voltammetry (DPV) peak current of methylene blue (MB). The aptasensor demonstrated a wide detection range for H3N2 from 10-1 to 106 PFU/mL, with a low detection limit (LOD) of 0.071 PFU/mL. It exhibited robust repeatability with a 3.7 % relative standard deviation (RSD) and high selectivity for H3N2 over SARS-CoV-2 and H1N1. Furthermore, the aptasensor successfully recognized H3N2 in clinical samples, showing a strong correlation between signal strength and virus loads, and accurately identifying negative samples. This aptamer-based electrochemical method offers enhanced accuracy, detection speed, and diagnostic convenience for point-of-care (POC) testing compared to molecular methods, benefiting from the aptamer's superior chemical stability and prolonged lifespan.