title: Single molecule tracking on supported membranes with arrays of optical nanoantennas.
abstract: Coupling of the localized surface plasmons between two closely apposed gold nanoparticles (nanoantenna) can cause strong enhancements of fluorescence or Raman signal intensity from molecules in the plasmonic "hot-spot". Harnessing these properties for practical applications is challenging due to the need to fabricate gold particle arrays with well-defined nanometer spacing and a means of delivering functional molecules to the hot-spot. We report fabrication of billions of plasmon-coupled nanostructures on a single substrate by a combination of colloid lithography and plasma processing. Controlled spacing of the nanoantenna gaps is achieved by taking advantage of the fact that polystyrene particles melt together at their contact point during plasma processing. The resulting polymer thread shadows a gap of well-defined spacing between each pair of gold triangles in the final array. Confocal surface-enhanced Raman spectroscopy imaging confirms the array is functionally uniform. Furthermore, a fully intact supported membrane can be formed on the intervening substrate by vesicle fusion. Trajectories of freely diffusing individual proteins are traced as they sequentially pass through, and are enhanced by, multiple gaps. The nanoantenna array thus enables enhanced observation of a fluid membrane system without static entrapment of the molecules.
authors.affiliation: Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: T
authors.initials: T
authors.lastname: Lohmüller
authors.forename: L
authors.initials: L
authors.lastname: Iversen
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.forename: C
authors.initials: C
authors.lastname: Rhodes
authors.forename: H-L
authors.initials: HL
authors.lastname: Tu
authors.forename: W-C
authors.initials: WC
authors.lastname: Lin
authors.forename: J T
authors.initials: JT
authors.lastname: Groves
mesh_terms: D006046:Gold / Q000737:chemistry*; D008027:Light; D008567:Membranes, Artificial; D015336:Molecular Probe Techniques; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D008567:Membranes, Artificial; D006046:Gold