Dual-mode probe based on mesoporous silica coated gold nanorods for targeting cancer cells.

A dual-mode imaging probe for targeting cancer cells has been fabricated based on mesoporous silica coated gold nanorods (MS-GNRs) for the first time. In this probe, fluorescence and surface enhanced Raman scattering (SERS) signals can be generated independently by using different excitation wavelengths. To investigate the targeting performance of the probe, folic acid (FA) is conjugated on the outer surfaces of MS-GNRs as a targeting ligand and HeLa cells were used as model cancer cells because they overexpress folate receptors (FRs). The endocytosis mechanism was verified by competing experiments with free FA through both fluorescence images and SERS mappings. Moreover, the cytotoxicity of the probe was remarkably reduced in comparison with the GNRs without the silica shell as proved by the results of MTT assay. Compared with traditional imaging probes, this new type of nanoprobe has great potential for multiplexed imaging in living cells, which can be easily realized by using fluorescence and SERS signals.