We present a novel core/shell SERS (surface enhanced Raman scattering) probe based on silica-coated gold nanoaggregates and its SERS application in living cells. It is found that the chemical stability and biocompatibility can be greatly improved by coating the gold nanoparticles with a layer of silica. In our experiments, 4MBA (4-mercaptobenzoicacid) is used not only as a Raman reporter, but also an aggregation agent. By coating the gold nanoparticles with the silica shell, the aggregation of gold nanoparticles can be controlled to optimize the SERS activity. TEM images and UV-Vis spectra were employed to investigate the core-shell structure of the probe and the aggregation degree of gold nanoparticles. The results exhibit the strong performance of SERS sensitivity and biocompatibility of the probe in living HeLa and SKBR3 cells, indicating its attraction in further application in intracellular environment.

Key words: SERS probe, gold nanoaggregates, silica shell, HeLa cell, SKBR3 cell