title: Strong reduction of spectral heterogeneity in gold bipyramids for single-particle and single-molecule plasmon sensing.
abstract: Single metal nanoparticles are attractive biomolecular sensors. Binding of analyte to a functional particle results in a plasmon shift that can be conveniently monitored in a far-field optical microscope. Heterogeneities in spectral properties of individual particles in an ensemble affect the reliability of a single-particle plasmon sensor, especially when plasmon shifts are monitored in real-time using a fixed irradiation wavelength. We compare the spectral heterogeneity of different plasmon sensor geometries (gold nanospheres, nanorods, and bipyramids) and correlate this to their size and aspect-ratio dispersion. We show that gold bipyramids exhibit a strongly reduced heterogeneity in aspect ratio and plasmon wavelength compared to commonly used gold nanorods. We show that this translates into a significantly improved homogeneity of the response to molecular binding without compromising single-molecule sensitivity.
authors.affiliation: Department of Applied Physics, Eindhoven University of Technology, Postbus 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: S M E
authors.initials: SM
authors.lastname: Peters
authors.forename: M A
authors.initials: MA
authors.lastname: Verheijen
authors.forename: M W J
authors.initials: MW
authors.lastname: Prins
authors.forename: P
authors.initials: P
authors.lastname: Zijlstra