title: Label-free single-particle imaging of the influenza virus by objective-type total internal reflection dark-field microscopy.
abstract: Here we report label-free optical imaging of single particles of the influenza virus attached on a glass surface with a simple objective-type total internal reflection dark-field microscopy (TIRDFM). The capability of TIRDFM for the imaging of single viral particles was confirmed from fine correlation of the TIRDFM images with fluorescent immunostaining image and scanning electron microscopy image. The density of scattering spots in the TIRDFM images showed a good linearity against the virus concentration, giving the limit of detection as 1.2×10(4) plaque-forming units per milliliter. Our label-free optical imaging method does require neither elaborated sample preparation nor complex optical systems, offering a good platform for rapid and sensitive counting of viral particles.
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, Japan.
authors.forename: Sawako
authors.initials: S
authors.lastname: Enoki
authors.forename: Ryota
authors.initials: R
authors.lastname: Iino
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Morone
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Kaihatsu
authors.forename: Shouichi
authors.initials: S
authors.lastname: Sakakihara
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Noji
mesh_terms: D005612:Freeze Drying / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods*; D009975:Orthomyxoviridae / Q000648:ultrastructure*; D012666:Semiconductors