title: Protein-Containing Lipid Bilayers Intercalated with Size-Matched Mesoporous Silica Thin Films.
abstract: Proteins are key components in a multitude of biological processes, of which the functions carried out by transmembrane (membrane-spanning) proteins are especially demanding for investigations. This is because this class of protein needs to be incorporated into a lipid bilayer representing its native environment, and in addition, many experimental conditions also require a solid support for stabilization and analytical purposes. The solid support substrate may, however, limit the protein functionality due to protein-material interactions and a lack of physical space. We have in this work tailored the pore size and pore ordering of a mesoporous silica thin film to match the native cell-membrane arrangement of the transmembrane protein human aquaporin 4 (hAQP4). Using neutron reflectivity (NR), we provide evidence of how substrate pores host the bulky water-soluble domain of hAQP4, which is shown to extend 7.2 nm into the pores of the substrate. Complementary surface analytical tools, including quartz crystal microbalance with dissipation monitoring (QCM-D) and fluorescence microscopy, revealed successful protein-containing supported lipid bilayer (pSLB) formation on mesoporous silica substrates, whereas pSLB formation was hampered on nonporous silica. Additionally, electron microscopy (TEM and SEM), light scattering (DLS and stopped-flow), and small-angle X-ray scattering (SAXS) were employed to provide a comprehensive characterization of this novel hybrid organic-inorganic interface, the tailoring of which is likely to be generally applicable to improve the function and stability of a broad range of membrane proteins containing water-soluble domains.
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-41296 Gothenburg, Sweden.
authors.forename: Simon
authors.initials: S
authors.lastname: Isaksson
authors.affiliation: Materials Physics and Application Division, MPA-11, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States.
authors.forename: Erik B
authors.initials: EB
authors.lastname: Watkins
authors.affiliation: Department of Pharmacy, Uppsala University , SE-75123 Uppsala, Sweden.
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Browning
authors.affiliation: Department of Biomedical Sciences and Biofilm-The Research Center for Biointerfaces, Health & Society, Malmo University , SE-20500 Malmo, Sweden.
authors.forename: Tania
authors.initials: T
authors.lastname: Kjellerup Lind
authors.affiliation: Department of Biomedical Sciences and Biofilm-The Research Center for Biointerfaces, Health & Society, Malmo University , SE-20500 Malmo, Sweden.
authors.forename: Marité
authors.initials: M
authors.lastname: Cárdenas
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg , SE-40530 Gothenburg, Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Hedfalk
authors.affiliation: Department of Applied Physics, Chalmers University of Technology , SE-41296 Gothenburg, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Höök
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-41296 Gothenburg, Sweden.
authors.forename: Martin
authors.identifier: 0000-0003-1523-4697
authors.initials: M
authors.lastname: Andersson
mesh_terms: D051401:Aquaporin 4 / Q000737:chemistry*; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D051401:Aquaporin 4; D008051:Lipid Bilayers; D012822:Silicon Dioxide
keywords: Aquaporin; Lipid bilayer; Liposome; Membrane protein; Neutron reflectivity; Silica