title: Antibody adsorption on the surface of water studied by neutron reflection.
abstract: Surface and interfacial adsorption of antibody molecules could cause structural unfolding and desorbed molecules could trigger solution aggregation, resulting in the compromise of physical stability. Although antibody adsorption is important and its relevance to many mechanistic processes has been proposed, few techniques can offer direct structural information about antibody adsorption under different conditions. The main aim of this study was to demonstrate the power of neutron reflection to unravel the amount and structural conformation of the adsorbed antibody layers at the air/water interface with and without surfactant, using a monoclonal antibody 'COE-3' as the model. By selecting isotopic contrasts from different ratios of H2O and D2O, the adsorbed amount, thickness and extent of the immersion of the antibody layer could be determined unambiguously. Upon mixing with the commonly-used non-ionic surfactant Polysorbate 80 (Tween 80), the surfactant in the mixed layer could be distinguished from antibody by using both hydrogenated and deuterated surfactants. Neutron reflection measurements from the co-adsorbed layers in null reflecting water revealed that, although the surfactant started to remove antibody from the surface at 1/100 critical micelle concentration (CMC) of the surfactant, complete removal was not achieved until above 1/10 CMC. The neutron study also revealed that antibody molecules retained their globular structure when either adsorbed by themselves or co-adsorbed with the surfactant under the conditions studied.
authors.affiliation: a Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester , Manchester , UK.
authors.forename: Charles
authors.initials: C
authors.lastname: Smith
authors.affiliation: a Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester , Manchester , UK.
authors.forename: Zongyi
authors.initials: Z
authors.lastname: Li
authors.affiliation: a Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester , Manchester , UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Holman
authors.affiliation: a Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester , Manchester , UK.
authors.forename: Fang
authors.initials: F
authors.lastname: Pan
authors.affiliation: b Institute of Laue Langevin , Grenoble , France.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Campbell
authors.affiliation: c ISIS Neutron Facility, STFC , Chilton, Didcot , UK.
authors.forename: Mario
authors.initials: M
authors.lastname: Campana
authors.affiliation: c ISIS Neutron Facility, STFC , Chilton, Didcot , UK.
authors.forename: Peixun
authors.initials: P
authors.lastname: Li
authors.affiliation: c ISIS Neutron Facility, STFC , Chilton, Didcot , UK.
authors.forename: John R P
authors.initials: JR
authors.lastname: Webster
authors.affiliation: d Formulation Sciences, MedImmune LLC , Gaithersburg , MD , USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Bishop
authors.affiliation: d Formulation Sciences, MedImmune LLC , Gaithersburg , MD , USA.
authors.forename: Rojaramani
authors.initials: R
authors.lastname: Narwal
authors.affiliation: e Formulation Sciences , MedImmune Ltd , Cambridge , UK.
authors.forename: Shahid
authors.initials: S
authors.lastname: Uddin
authors.affiliation: e Formulation Sciences , MedImmune Ltd , Cambridge , UK.
authors.forename: Christopher F
authors.initials: CF
authors.lastname: van der Walle
authors.affiliation: a Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester , Manchester , UK.
authors.forename: Jian R
authors.initials: JR
authors.lastname: Lu
mesh_terms: D000327:Adsorption; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D006801:Humans; D033363:Neutron Diffraction / Q000379:methods*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D013501:Surface-Active Agents; D014867:Water
keywords: Antibody; co-adsorption; mAbs; neutron reflection; self-assembly; structural unfolding; surface adsorption; surfactant