Low Background Cascade Signal Amplification Electrochemical Sensing Platform for Tumor-Related mRNA Quantification by Target-Activated Hybridization Chain Reaction and Electroactive Cargo Release

Herein a low background cascade signal amplification electrochemical sensing platform has been proposed for the ultrasensitive detection of mRNA (mRNA) by coupling the target-activated hybridization chain reaction and electroactive cargo release from mesoporous silica nanocontainers (MSNs). In this sensing platform, the 5′-phosphate-terminated DNA (5′-PO4 cDNA) complement to target mRNA is hybridized with the trigger DNA and anchor DNA on the surface of the MSNs, aiming at forming a double-stranded DNA gate molecule and sealing the methylene blue (MB) in the inner pores of the MSNs. In the presence of target mRNA, the 5′-PO4 cDNA is displaced from the MSNs and competitively hybridizes with mRNA, which led to the liberation of the trigger DNA and the opening of the MSNs pore. The liberated trigger DNA can be then immobilized onto the electrode surface through hybridization with the capture DNA, triggering HCR on the electrode surface. At the same time, the MB released from the MSNs will selectively interca...