title: Observations of immuno-gold conjugates on influenza viruses using waveguide-mode sensors.
abstract: Gold nanoparticles were conjugated to an antibody (immuno-AuNP) against A/Udorn/307/1972 (H3N2) influenza virus to detect viruses on a sensing plate designed for an evanescent field-coupled waveguide-mode sensor. Experiments were conducted using human influenza A/H3N2 strains, and immuno-AuNP could detect 8×10(5) PFU/ml (40 pg/µl) intact A/Udorn/307/1972 and 120 pg/µl A/Brisbane/10/2007. Furthermore, increased signal magnitude was achieved in the presence of non-ionic detergent, as the virtual detection level was increased to 8×10(4) PFU/ml A/Udorn/307/1972. Immuno-AuNPs were then complexed with viruses to permit direct observation, and they formed a ring of confined nanodots on the membrane of both intact and detergent-treated viruses as directly visualized by scanning electron microscopy. With this complex the detection limit was improved further to 8×10(3) PFU/ml on anti-rabbit IgG immobilized sensing plate. These strategies introduce methods for observing trapped intact viruses on the sensing plates generated for optical systems.
authors.affiliation: Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan. gopi-subashchandrabose@aist.go.jp
authors.forename: Subash C B
authors.initials: SC
authors.lastname: Gopinath
authors.forename: Koichi
authors.initials: K
authors.lastname: Awazu
authors.forename: Makoto
authors.initials: M
authors.lastname: Fujimaki
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Shimizu
authors.forename: Takayuki
authors.initials: T
authors.lastname: Shima
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D004285:Dogs; D006046:Gold / Q000008:administration & dosage*; D006801:Humans; D018796:Immunoconjugates / Q000008:administration & dosage* / Q000276:immunology; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D007251:Influenza, Human / Q000175:diagnosis* / Q000276:immunology; D061985:Madin Darby Canine Kidney Cells; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D008855:Microscopy, Electron, Scanning / Q000379:methods
chemical_list: D000906:Antibodies; D018796:Immunoconjugates; D006046:Gold