Improved properties of gold nanorods coated with thin multilayer of small organic molecules by fast and facile method for surface enhanced Raman scattering
We introduce a thin multilayer-shell-coated gold nanorods (GNRs) that we have been able to achieve by way of coating them with two thin layers of small organic molecules in a new, efficient, effective, time-saving, and easy-to-control multilayer coating method. Compared to the thick shell, due to the small size of the coating molecules, this new type of GNR, by simply mixed with the sample solution, has shown that it can act as a highly effective and improved surface enhanced Raman scattering (SERS) enhancement agent without the need of any sample connecting or doping. This enhancement is found not only related to the off-resonance surface enhancement, but also to the increased signal-to-noise ratio brought by the low level of fluorescence emission. It showed excellent stability in strong acids, bases and some organic solvents as examined by comparing the longitudinal surface plasmon resonance peak values. A living body experiment on a tumor-bearing nude mouse injected with the Raman reporter dye loaded onto our new GNRs showed strong surface enhanced Raman scattering signal in the tumor, suggesting its high potential use in many related optical applications.
gold nanorods multilayer surface enhanced raman scattering surface plasmon resonance tumor fluorescence quench