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 FeO@SiO magnetic nanoparticles (FeO@SiO MNPs). Here, FeO@SiO MNPs were used as a separation substrate, and Au@AgNPs served as stable and ultrasensitive SERS nanotags. Firstly, Au@AgNPs and FeO@SiO 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 FeO@SiO 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.