We report the development of spectrally encoded nanoparticles based on surface-enhanced Raman scattering (SERS) to study the complex behavior of both passive and active nanoparticles under physiological conditions. This class of multiplexable nanoparticles has allowed us to engineer a cocktail combination of nanoparticles with nearly identical hydrodynamic size, electrical charge, and surface coatings. In particular, bot the active- and passive-targeted particles share the same core size of metal nanoparticle (60 nm) and similar polyethyleneglycol (PEG) polymer coatings. The difference between the two particles is that the targeted particles have multiple targeting ligands on the outer layer whereas control particles have a complete PEG layer to minimize non-specific interactions with blood. Using near infrared 785 nm laser excitation, we have recorded the pharmacokinetic profiles for both active and passive targeting nanoparticles in a noninvasive manner. A key point is that mouse-to-mouse variations are avoided by injecting a mixture of the two particles into the same animal.  Using spectral deconvolution, we have mapped the spatial distribution of targeted versus non-targeted nanoparticles in xenograft tumors.  The mapping data showed a similar level of total tumor accumulation between the targeted and non-targeted SERS nanoparticles, but the presence of targeting ligands was found to play a significant role in the intra-tumoral distribution of nanoparticles. Non-targeted nanoparticles showed higher localized concentrations near blood vessels, while targeted nanoparticles were more diffusely localized. In summary, this class of multiplexed nanoprobes raises new possibilities not only in examining the in-vivo behavior of nanoparticles but also in tagging and tracking tumor stem cells, stromal cells, and epithelial cells.

Encoded SERS nanoprobes: In-vivo spectroscopic detection of single nanoparticles and single tumor cells

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.