Simple Route for Preparing Optically Trappable Probes for Surface-Enhanced Raman Scattering

Surface-enhanced Raman scattering (SERS) has proven to be a powerful technique for a wide range of topics such as chemical analysis, materials research, and biological imaging. In this work, we report in detail on the development and characterization of micrometer-sized dielectric beads with metal colloids attached to their surface. The metalized beads were Sufficiently transparent enabling optical trapping while the presence of metal islands provided the SERS. This method is fast and simple and is void of complications when compared to the Tollen's test used in previous publications. This highly efficient probe can be placed and scanned with nanometric accuracy near living cells. The process to create such probes is described including discussion of various parameters that are critical in achieving the desired results. Additionally, their use is demonstrated by detecting low quantities of a drug in aqueous solution and in a cell membrane.