A simple and rapid detection assay for peptides based on the specific recognition of aptamer and signal amplification of hybridization chain reaction

• The hybridization chain reaction, which is a enzyme-free amplification reaction,, is simple and low in cost.
• The aptamer can not only identify target peptides, but also initiate the HCR, and the background is greatly reduced due to the quenching effect of GO.
• The novel assay shows great sensitivity in the detection of peptide and has great potential in various peptides and even cells.

A simple and rapid assay for the detection of peptides is designed based on the specific recognition of aptamer, the quenching effect of graphene oxide (GO) and the efficient signal amplification of hybrid chain reaction (HCR). In this assay, the hairpin structure of aptamer is opened after binding with targets, and the initiation sequence could be exposed to hairpin probe 1 (H1) to open its hairpin structure. Then the opened H1 will open the hairpin structure of hairpin probe 2 (H2), and in turn, the opened initiation sequence of H2 continues to open H1. As a result, the specific recognition of target and fluorescent signals are accumulated through the process in short 1 h. Attentively, the aptamer can not only identify target peptides, but also initiate the HCR between H1 and H2. More importantly, the HCR is initiated only after the target recognition of aptamer. After HCR, the excess hairpin probes will be anchored on the GO surface, and the background is greatly reduced due to the quenching effect of GO. By using Mucin-1(MUC1) as a model peptide, the assay has a wide linear range as two orders of magnitude and the detection range is from 0.01 to 5 nM with low detection limit of 3.33 pM. Therefore, the simple and rapid detection of the target can be realized, and the novel assay has great potential in detecting various peptides and even cancer cells.