Fe3O4@Ag magnetic nanoparticles for microRNA capture and duplex specific nuclease signal amplification based SERS detection in cancer cells.
A functionalized Fe3O4@Ag magnetic nanoparticle (NP) biosensor for microRNA (miRNA) capture and ultrasensitive detection in total RNA extract from cancer cells was reported in this paper. Herein, Raman tags DNA probes modified Fe3O4@Ag NPs were designed both as surface enhanced Raman scattering (SERS) SERS and duplex specific nuclease signal amplification (DSNSA) platform. Firstly, target miRNAs were captured to the surface of Fe3O4@Ag NPs through DNA/RNA hybridization. In the presence of endonuclease duplex specific nuclease (DSN) one target miRNA molecule could rehybrid thousands of DNA probes to trigger the signal amplifying recycling. Base on the superparamagnetic of Fe3O4@Ag NPs, target miRNA let 7b can be captured, concentrated and direct quantified within a PE tube without any PCR preamplification treatment. The detection limit was 0.3fM (15 zeptomole, 50mL) nearly 3 orders of magnitude lower than conventional fluorescence based DSN biosensors for miRNA(~100fM) even single base difference between the let 7 family members can be discriminated. The result provides a novel proposal to combine the perfect single base recognition and signal amplifying ability of the endonuclease DSN with cost effective SERS strategy for miRNA point of care (POC) clinical diagnostics.
Biosensors bioelectronics