Simultaneous detection of tumor-related mRNA and miRNA in cancer cells with magnetic SERS nanotags

The design of simultaneous detection method has broad prospects for cancer diagnosis and prognosis. Herein, we reported a low cost and sensitive SERS sensing platform for simultaneous p21 mRNA and miRNA-21 detection based on duplex-specific nuclease signal amplification (DSNSA) plus multifunctional Fe 3 O 4 @SiO 2 magnetic nanoparticles (Fe 3 O 4 @SiO 2 MNPs). Here, Fe 3 O 4 @SiO 2 MNPs were used as a separation substrate, and Au@AgNPs served as stable and ultrasensitive SERS nanotags. Firstly, Au@AgNPs and Fe 3 O 4 @SiO 2 MNPs were attached to both ends of capture probe (CP) by covalent bonds. Under the assistance of the target p21 mRNA and miRNA-21, DNA (CP) of the DNA-RNA heteroduplexes could be specifically degraded by DSN and the SERS nanotags that were released from the surface of Fe 3 O 4 @SiO 2 MNPs. Meanwhile, the target p21 mRNA and miRNA-21 were released and then involved in the next round of signal reactions. The proposed strategy allowed quantitative detection of p21 mRNA and miRNA-21 and the limit of detection (LOD) was 0.12 fM and 0.17 fM, respectively. This method gives a great potential for multiplex detection of biological molecules. • DSN-assisted SERS platform for simultaneous p21 mRNA and microRNA-21 detection is reported. • Fe 3 O 4 @SiO 2 magnetic nanoparticles were used as a separation substrate and Au@AgNPs served as ultrasensitive SERS nanotags. • The limit of detection was 0.12 fM and 0.17 fM for p21 mRNA and microRNA-21. • The SERS platform can quantify the expression level of the p21 mRNA and microRNA-21 in real samples.