Au-Ag alloy/porous-SiO2 core/shell nanoparticle-based surface-enhanced Raman scattering nanoprobe for ratiometric imaging analysis of nitric oxide in living cells.

2 In this paper, we developed a novel surface-enhanced Raman scattering (SERS) nanoprobe via the assembly of 3,4-diaminobenzene-thiol on the surface of porous SiO2-coated Au-Ag alloy nanoparticles and successfully applied this for ratiometric imaging analysis of NO in living cells. This nanoprobe exhibits excellent biocompatibility and chemical stability, superior SERS enhancement capacity, and good signal reproducibility. To the best of our knowledge, this is the first report of a porous SiO2-coated Au-Ag alloy nanoparticle and ratiometric-based SERS nanosensor to be used for the detection of NO in living cells.