title: Gold nanoparticles as spectroscopic enhancers for in vitro studies on single viruses.
abstract: Gold particles with diameters between 2.5 and 4.5 nm have been introduced in the inner cavity of an icosahedral brome mosaic virus. The optical properties of single gold-marked virions have been tested in-vitro with respect to the characteristic plasmon polariton resonance. The shift in the plasmon polariton resonance of a single Au particle encapsulated in a virus with respect to a free particle in solution indicates a close interaction between the basic residues on the inner wall of the capsid and the negative surface charge of the particle. Incorporation of a pair of Au particles, approximately 4 nm diameter, is shown to be a frequent event. In this case, the dependence of the two-particle surface plasmon spectrum on the interparticle distance and the strong particle/capsid wall interaction suggest that, in the future, it will be possible to use encapsulated Au particles to track changes in the viral capsid volume in real-time and in a physiological environment.
authors.affiliation: Department of Chemistry and Department of Biology, Indiana University, Bloomington, Indiana 47405, USA. dragnea@indiana.edu
authors.forename: Bogdan
authors.initials: B
authors.lastname: Dragnea
authors.forename: Chao
authors.initials: C
authors.lastname: Chen
authors.forename: Eun-Soo
authors.initials: ES
authors.lastname: Kwak
authors.forename: Barry
authors.initials: B
authors.lastname: Stein
authors.forename: C Cheng
authors.initials: CC
authors.lastname: Kao
mesh_terms: D017795:Bromovirus / Q000737:chemistry*; D002213:Capsid / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D008854:Microscopy, Electron; D036103:Nanotechnology / Q000379:methods*; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman
chemical_list: D006046:Gold