Surface Enhanced Raman Scattering Encoded Gold Nanostars for Multiplexed Cell Discrimination

Labeled nanoparticles have attracted much interest toward applications in bioimaging and diagnostics. In particular, surface enhanced Raman scattering (SERS) nanotags have been demonstrated to be excellent candidates for multiplexed imaging and biological detection. We propose an alternative, effective method to easily prepare gold nanostars exhibiting plasmon bands in the near-infrared range, encoded with Raman reporter molecules, concomitantly acting as capping agents which are then protected with an amphiphilic polymer. The resulting nanotags are noncytotoxic and display long-term stability against aggregation and reporter leakage, while showing reproducible SERS signals suitable for multiplexing. These tags were used to distinguish five different types of breast cancer cells by imaging of a quintuple cell coculture. Time-lapse SERS imaging of the coculture was additionally performed, demonstrating the applicability of these nanotags for cell tracing over time scales above 24 h.