Polymer-decorated Plasmonic Nanoparticles

The preparation and characterization of noble metal nanoparticles that are coated by organic shells for the covalent immobilization of biopolymers were described. Plasmonic nanoparticles demonstrate unique size-dependent optical and photothermal properties due to the collective oscillation of free electrons in their conduction bands. The intensity of absorption and scattering of noble metal nanoparticles is significantly higher than most absorbing and scattering organic molecular dyes, which makes them excellent candidates as contrast agents in imaging. Cylindrical gold nanorods also demonstrate a tunable photothermal response to near infrared light as a function of nanoparticle aspect ratio. Organic functional groups on the nanoparticles allow the coupling of organic molecules to their shells. Several synthetic approaches to couple biomolecules to metal nanoparticles and to use the hybrid assemblies for various bioanalytical applications have been reported.