An interface-engineered signal-on electrochemical aptasensor for H5N2 avian influenza virus detection

초록

Outbreaks of avian influenza virus (AIV) cause substantial economic losses in the poultry industry, highlighting the need for sensitive, reliable and field-adaptable detection platforms. In this study, we report a signal-on electrochemical aptasensor for avian influenza virus H5N2(K08-404) by translating a previously reported J3/JH4 cognate aptamer pair into an electrode-confined sandwich sensing format. The simultaneous binding capability of this aptamer pair enabled target-mediated recruitment of the HRP-labeled reporter aptamer and generated a signal-on amperometric response. This signal-on aptasensor was successfully fabricated by immobilizing the primary aptamer on the screen-printed gold electrode followed by the addition of a mixture of the target virus and the secondary aptamer labeled with horseradish peroxidase, thereby generating amplified signal-on electrochemical responses. The fabrication of the sandwich-type aptasensor was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Decreased peak currents and increased peak-to-peak separation supported the stepwise assembly of the electrochemical sensing interface. Analytical performance was evaluated at various virus concentrations using chronoamperometry, revealing a concentration-dependent increase in current response. The aptasensor achieved LODs of 2.00 & times; 104 EID50 per mL in a buffer and 2.76 & times; 104 EID50 per mL in a processed duck fecal matrix, with linear working ranges of 3.91 & times; 104-4.17 & times; 105 EID50 per mL and 1.95 & times; 104-1.25 & times; 106 EID50 per mL, respectively. These results support the feasibility of converting a previously validated H5N2 aptamer pair into a quantitative electrochemical platform for surveillance-oriented virus detection.

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