Mesoporous Silica Containers and Programmed Catalytic Hairpin Assembly/Hybridization Chain Reaction Based Electrochemical Sensing Platform for miRNA Ultrasensitive Detection with Low Background

In this work, based on mesoporous silica containers (MSNs) with the programmed enzyme-free DNA assembly amplification of catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR), an ultrasensitive electrochemical sensing platform with low background is developed for the detection of microRNA (miRNA). Herein, the electrochemical reporter methylene blue (MB) was sealed in the pores of MSNs by the double-stranded DNA (dsDNA) gate of hairpin DNA H1 and anchor DNA. In the absence of target, neither the CHA nor the HCR process happened, which enabled a low background. After target was added, DNA H1 was displaced from the MSNs surface and participated in the CHA process with the assistance of hairpin DNA H2, which accelerated the release of MB from the MSNs pore. Meanwhile, the CHA products H1–H2 were hybridized with the capture probes (SH–CP) on the electrode surface, which further initiated the HCR process. The released MB from the MSNs will effectively intercalate into long dsDNA polymers of HC...