A simple and label-free proximity-catalytic hairpin reaction-based method for sensitive and miRNA analysis

Aberrant expression of microRNAs (miRNAs) has been shown to be linked to several crucial biological processes, including as carcinogenesis, metastasis, and progression. The advancement of innovative miRNA detection technologies can enhance the early detection of malignancies by merging with conventional diagnostic methods, such as ultrasound technology. Herein, we reported a simple, sensitive, and label-free miRNA detection method by integrating the proximity-catalytic hairpin assembly (proximity-CHA) and DNAzyme-assisted signal amplification. Compared with traditional CHA, in which the signal amplification efficiency is greatly limited by the concentration of hairpin probes, the proposed method possesses a greatly improved signal amplification efficiency. The target facilitated the non-enzymatic CHA-driven sequential formation of DNAzyme nanostructures, resulting in the effective DNAzyme-facilitated cleavage of a substrate modified with a fluorophore and quencher, leading to the production of an intensified fluorescence signal. The proximity-CHA-DNAzyme system possesses appealing analytical characteristics, making it highly promising for the analysis of many analytes in clinical research domains.