Fast-response electrochemical biosensor based on a truncated aptamer and MXene heterolayer for West Nile virus detection in human serum.

West Nile virus (WNV) is a mosquito-borne flavivirus that can cause West Nile fever, meningitis, encephalitis, and polio. Early detection of WNV is important to prevent infection spread on the field. To commercialize the electrochemical biosensor for WNV, rapid target detection with the cheap manufacture cost is essential. Here, we developed a fast-response electrochemical biosensor consisting of a truncated WNV aptamer/MXene (Ti3C2Tx) bilayer on round-type micro gap. To reduce the target binding time, the application of the alternating current electrothermal flow (ACEF) technology reduced the target detection time to within 10 min, providing a rapid biosensor platform. The MXene nanosheet improved electrochemical signal amplification, and the aptamer produced through systematic evolution of ligands by exponential enrichment process eliminated unnecessary base sequences via truncation and lowered the manufacturing cost. Under optimized conditions, the WNV limit of detection (LOD) and selectivity were measured using electrochemical measurement methods, including cyclic voltammetry and square wave voltammetry. The LOD was 2.57 pM for WNV diluted in deionized water and 1.06 pM for WNV diluted in 10% human serum. The fabricated electrochemical biosensor has high selectivity and allows rapid detection, suggesting the possibility of future application in the diagnosis of flaviviridae virus.