Plasmonic gold and luminescent silicon nanoplatforms for multimode imaging of cancer cells.

The development of multimodal nanoparticle platforms is desirable for cancer nanotechnology applications. Creating single nanoplatforms with both plasmonic and photoluminescent optical properties has remained a challenge, because combining discrete entities each having one of these unique properties typically results in the attenuation of one of the desirable properties. Here, we overcome challenges associated with combining plasmonic gold with luminescent silicon nanocrystals for biological imaging applications by incorporating multiple silicon quantum dots into the core of a micelle and then depositing gold on the surface of the nanostructure. Within the newly developed nanoconstruct, the gold shell exhibits plasmonic light scattering properties useful for dark field imaging, while the silicon nanocrystals maintain their photoluminescence. The result is a nanoplatform with both plasmonic and luminescent properties in a useful form. Multimodal imaging of pancreatic cancer cells demonstrates overlap of luminescence from the silicon quantum dots with light scattering from the gold shell. This approach can be tailored to other formulations and address the challenge of fluorescence attenuation that is typically observed when quantum dots are combined with plasmonic materials. The usefulness of these particles may eventually extend beyond multimodal imaging to include photothermal treatment.