title: Physicochemical Study of Viral Nanoparticles at the Air/Water Interface.
abstract: The assembly of most single-stranded RNA (ssRNA) viruses into icosahedral nucleocapsids is a spontaneous process driven by protein-protein and RNA-protein interactions. The precise nature of these interactions results in the assembly of extremely monodisperse and structurally indistinguishable nucleocapsids. In this work, by using a ssRNA plant virus (cowpea chlorotic mottle virus [CCMV]) as a charged nanoparticle we show that the diffusion of these nanoparticles from the bulk solution to the air/water interface is an irreversible adsorption process. By using the Langmuir technique, we measured the diffusion and adsorption of viral nucleocapsids at the air/water interface at different pH conditions. The pH changes, and therefore in the net surface charge of the virions, have a great influence in the diffusion rate from the bulk solution to the air/water interface. Moreover, assembly of mesoscopic and microscopic viral aggregates at this interface depends on the net surface charge of the virions and the surface pressure. By using Brewster's angle microscopy we characterized these structures at the interface. Most common structures observed were clusters of virions and soap-frothlike micron-size structures. Furthermore, the CCMV films were compressed to form monolayers and multilayers from moderate to high surface pressures, respectively. After transferring the films from the air/water interface onto mica by using the Langmuir-Blodgett technique, their morphology was characterized by atomic force microscopy. These viral monolayers showed closed-packing nano- and microscopic arrangements.
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí , Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí, México.
authors.forename: Jose F
authors.initials: JF
authors.lastname: Torres-Salgado
authors.affiliation: HIV Dynamics and Replication Program, National Cancer Institute , Frederick, Maryland 21702, United States.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Comas-Garcia
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí , Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí, México.
authors.forename: Maria V
authors.initials: MV
authors.lastname: Villagrana-Escareño
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí , Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí, México.
authors.forename: Ana L
authors.initials: AL
authors.lastname: Durán-Meza
authors.affiliation: Instituto de Física, Universidad Autónoma de San Luis Potosí , Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí, México.
authors.forename: Jaime
authors.initials: J
authors.lastname: Ruiz-García
authors.affiliation: Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México , Carretera Tijuana-Ensenada Km. 107, 22860 Ensenada, Baja California, México.
authors.forename: Ruben D
authors.initials: RD
authors.lastname: Cadena-Nava
mesh_terms: D000327:Adsorption; D000388:Air / Q000032:analysis*; D017795:Bromovirus / Q000737:chemistry*; D004058:Diffusion; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D018625:Microscopy, Atomic Force; D019251:Nucleocapsid / Q000737:chemistry*; D012367:RNA, Viral / Q000737:chemistry*; D055672:Static Electricity; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014771:Virion / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D012367:RNA, Viral; D014867:Water