Detection technologies employing optically encoded particles have gained much interest toward clinical diagnostics and drug discovery, but the portfolio of available systems is still limited. We report the fabrication and characterization of highly stable surface enhanced Raman scattering (SERS)-encoded colloids, for the identification and imaging of proteins expressed in cells. Two different approaches were developed to synthesize the plasmonic nanostructures; a) gold octahedra coated with poly(isopropylacrylamide) (Au@pNIPAM) microgels, that can be readily encoded with Raman active dyes while retaining high colloidal stability in biofluids, and b) plasmonic nanoparticles encapsulated within zeolitic imidazolate frameworks (ZIF-8) that can be easily doped with different Raman reporters (see Figure A)<br/>A layer-by-layer polyelectrolyte coating was used to seal the outer surface of the pNIPAM encoded particles and to provide a reactive surface for covalent conjugation with antibodies. On the other hand, the ZIF-8 coating of the particles allowed its direct bio conjugation with His-tagged proteins.<br/>The targeted multiplexing capabilities of the SERS tags was demonstrated by the simultaneous detection and imaging of three tumor-associated surface biomarkers EGFR, EpCAM and CD44 by Raman spectroscopy (see Figure B and C). The plasmonic microgels were able to discriminate tumor A431 (EGFR+/EpCAM+/CD44+) and non-tumor 3T3 2.2 (EGFR-/EpCAM-/CD44+) cells while co-cultured <i>in vitro</i>.

SERS tags for multiplex immunophenotyping cellular receptors

252nd National Meeting (2016)

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