Split-DNAzyme cooperating primer exchange reaction for sensitive miRNA detection

Abstract

Sensitive quantification of microRNA (miRNA) plays a crucial role in early diagnosis and precise therapy of osteosarcoma. Herein, we build a label-free and sensitive miRNA quantification approach based on the activation of split-DNAzyme initiated primer exchange reaction (PER). Target miRNA cooperates the activation of split-DNAzyme with Mg2+ through assisting the assembly of DNAzyme to correct conformation, which enables the performance of PER-based nucleic acids amplification to produce a large amount of single-strand DNA (ssDNA) sequences. The G-quadruplexes (G4) in ssDNA sequences products bind with N-methyl mesoporphyrin IX (NMM) to form G4-NMM complex with the enhanced fluorescence respond. The results demonstrate that miRNA-21 can assist the activation of split-DNAzyme, and the active DNAzyme exhibits a high specificity and efficiency in inducing the subsequent PER. Based on the split-DNAzyme-assisted signal recycle and PER, the method eventually shows a high sensitivity and selectivity, providing a promising prospect for the for early stage tumor diagnosis and more precise tumor therapy.