Construction of electrochemiluminescence biosensor via click chemistry and ARGET-ATRP for detecting tobacco mosaic virus RNA

Herein, an electroluminescence (ECL) biosensor was constructed by combining click chemistry with activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP) to sensitively assay tobacco mosaic virus (TMV) RNA for the first time. First, hairpin DNA (hDNA) was self-assembled on the gold electrode surface through Au-S bonding. The hDNA hybridized with the tDNA to form tRNA/hDNA hybrids in the presence of TMV RNA (tRNA), so that the azide group labelled at the end of the hDNA was kept away from the electrode surface. Subsequently, the initiator for the ARGET-ATRP reaction was modified on the electrode surface by chemical bonds via click chemistry. Then, N-acryloxysuccinimide (NAS)-labelled polymer chains were successfully formed on the electrode surface by ARGET-ATRP. Under the optimized conditions, a good linear relationship existed with the ECL signal and the logarithm of tRNA concentration in the range of 0.1 pM-10 nM, and the limit of detection was 2.61 fM. In addition, this strategy can identify mismatched bases and performs well in recovery assays in real samples. For its high sensitivity, selectivity, simplicity and economy, the ECL biosensor shows great potential for practical applications.