confirming the successful ‘‘Click’’ between core and satellites
(Fig. 4). The bands at 1079 cmꢁ1 and 1587 cmꢁ1 correspond to
p-ATP that was conjugated to the alkyl linker and subsequently
used to functionalize the satellites. These intense Raman bands
even from individual core–satellite structures make them highly
promising SERS tags.
In conclusion, we have demonstrated covalently-linked
plasmonic core–satellite structures using the ‘‘cream of the
crop’’ Click reaction.10 Such highly SERS-active plasmonic
nanoassemblies can find important applications in numerous
biomedical applications including biosensing and bioimaging.17,22
Facile fabrication of such complex assemblies can be easily
extended to different shape-controlled plasmonic nanostructures
and other functional inorganic nanostructures such as magnetic
nanoparticles, semi-conducting quantum dots and up-conversion
nanocrystals.
Fig. 3 Dynamic light scattering (DLS) measurements showing the
hydrodynamic diameter of individual cores, satellites and ‘‘clicked’’
core–satellite clusters. Inset shows a photograph of cores, satellites and
core–satellite cluster solutions.
We acknowledge I-CARES, Washington University in Saint
Louis for financial support and Nano Research Facility
(NRF), a member of the National Nanotechnology Infra-
structure Network (NNIN), for providing access to electron
microscopy facilities.
Notes and references
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c
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This journal is The Royal Society of Chemistry 2012