Robust discrimination between single gold nanoparticles and their dimers in aqueous solution for ultrasensitive homogeneous bioassays

Jun Kobayashi, Yukari Takeshita, Naoto Mizuno, Keio Esashika, Toshiharu Saiki

    Research output: Contribution to journalArticle

    2 Citations (Scopus)

    Abstract

    We propose a robust method to distinguish isolated single gold nanoparticles (AuNP monomers) and their dimers under Brownian motion, a key for ultrasensitive homogeneous bioassays, including AuNP sandwich assays. To detect dimers and distinguish them from a larger number of monomers in aqueous solution, single-particle polarization microscopy was performed. For the accurate detection of individual particles, the optical anisotropy and rotational diffusion time are measured because a dimer is much more anisotropic than the nearly spherical monomer and the rotational diffusion time of a dimer is four times that of a monomer. By employing an autocorrelation analysis, we defined a measure of distinguishing that simultaneously enables high detection probability and low error probability. The detection platform offers homogeneous DNA hybridization assays and immunoassays at the subpicomolar level.

    Original languageEnglish
    Article number581381
    JournalAdvances in Optical Technologies
    Volume2015
    DOIs
    Publication statusPublished - 2015 Jan 1

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Atomic and Molecular Physics, and Optics

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