title: Nanophotonic detection of freely interacting molecules on a single influenza virus.
abstract: Biomolecular interactions, such as antibody-antigen binding, are fundamental to many biological processes. At present, most techniques for analyzing these interactions require immobilizing one or both of the interacting molecules on an assay plate or a sensor surface. This is convenient experimentally but can constrain the natural binding affinity and capacity of the molecules, resulting in data that can deviate from the natural free-solution behavior. Here we demonstrate a label-free method for analyzing free-solution interactions between a single influenza virus and specific antibodies at the single particle level using near-field optical trapping and light-scattering techniques. We determine the number of specific antibodies binding to an optically trapped influenza virus by analyzing the change of the Brownian fluctuations of the virus. We develop an analytical model that determines the increased size of the virus resulting from antibodies binding to the virus membrane with uncertainty of ± 1-2 nm. We present stoichiometric results of 26 ± 4 (6.8 ± 1.1 attogram) anti-influenza antibodies binding to an H1N1 influenza virus. Our technique can be applied to a wide range of molecular interactions because the nanophotonic tweezer can handle molecules from tens to thousands of nanometers in diameter.
authors.affiliation: Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Pilgyu
authors.initials: P
authors.lastname: Kang
authors.affiliation: Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Perry
authors.initials: P
authors.lastname: Schein
authors.affiliation: School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Xavier
authors.initials: X
authors.lastname: Serey
authors.affiliation: School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Dakota
authors.initials: D
authors.lastname: O'Dell
authors.affiliation: Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853, USA.
authors.forename: David
authors.initials: D
authors.lastname: Erickson
mesh_terms: D000914:Antibodies, Viral / Q000737:chemistry* / Q000276:immunology*; D000937:Antigen-Antibody Reactions / Q000276:immunology*; D000067493:Dynamic Light Scattering / Q000379:methods; D053118:Influenza A Virus, H1N1 Subtype / Q000737:chemistry* / Q000276:immunology*; D036103:Nanotechnology / Q000379:methods*; D052898:Optical Tweezers; D013194:Staining and Labeling / Q000379:methods
chemical_list: D000914:Antibodies, Viral