Target-triggered regioselective assembly of nanoprobes for Raman imaging of dual cancer biomarkers in living cells.

• A target-triggered assembly strategy for Raman imaging of dual cancer biomarkers. • Two detection pathways are independent to produce strong SERS signals. • A potential tool to monitor the expression level of TE and mir-21 in different cell. Imaging multiple classes of intracellular cancer biomarkers provides invaluable insight into the tumor progression and allows cancer diagnosis at the molecular level. The challenge is to develop sensitive, selective and reliable methods for simultaneously imaging different types of cancer biomarkers at low concentrations. Herein, we demonstrated a target-triggered regioselective assembly strategy of plasmonic nanoprobes for dual Raman imaging of microRNA-21 (mir-21) and telomerase (TE) in cells. In the presence of TE, the intense signal of Raman reporter DTNB locating at the "hot spots" of end assembly probes (Au nanoparticles anchored on the terminal of Au nanorods) become weak once the TE triggers the dissociation of end assembly probes and release the DTNB-modified Au nanoparticles from the Au nanorods. Target mir-21 can trigger catalytic hairpin assembly amplification as catalysts and results in the formation of side nanoassemblies that Raman reporter Rox-modified Au nanoparticles anchored onto the side surface of Au nanorods, leading to enhancement in Rox signal. The two independent pathways can efficiently localize target analytes toward "hot spots" to produce strong, amplified SERS signals for the expression level and the dynamic change of mir-21 and TE in different cell lines, providing a potential tool for cancer diagnosis and progression monitor. [ABSTRACT FROM AUTHOR]