The invention provides a triple
signal amplification electrochemical method for detecting a
porcine reproductive and respiratory syndrome virus NADC30-like strain. Firstly, the surface of a gold
electrode is modified with a hairpin
signal probe H1, when a target sequence appears, the hairpin H1 is opened, a sequence capable of triggering a hybridization
chain reaction (HCR) is exposed, long dsDNA is formed, and first
signal amplification is achieved. Then, under the
catalysis of
terminal deoxynucleotidyl transferase (TdT), a large amount of polythymine (PolyT) extends from 3'terminal hydroxyl groups of H2 and H3 fragments, and second
signal amplification is realized; polyT serves as a template, in-situ deposition of a large amount of CuNPs is caused in a short time, the
signal response of the electrochemical sensor is remarkably enhanced, and third
signal amplification is achieved. And finally, monitoring
metal ions released by
dissolution of the nanoparticles by using a
differential pulse voltammetry, and drawing a
standard curve through current change to realize accurate quantification of the target
virus. The method is high in sensitivity and good in specificity, and can be used for general detection of viruses by replacing a target
virus specific sequence and a corresponding probe.