1. In situ X-ray reflectivity studies of molecular and molecular-cluster intercalation within purple membrane films
- Author
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Noor Haida Mohd Kaus, Wuge H. Briscoe, Oier Bikondoa, Jennifer M. Bulpett, Philip T. Cresswell, Stephen Mann, Andrew Collins, University of Bristol [Bristol], Universiti Sains Malaysia (USM), Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England, and European Synchrotron Radiation Facility (ESRF) more...
- Subjects
Nanocomposite ,Materials science ,Aqueous solution ,[SDV]Life Sciences [q-bio] ,Intercalation (chemistry) ,General Chemistry ,X-ray reflectivity ,chemistry.chemical_compound ,Crystallography ,Membrane ,Lamellar phase ,chemistry ,Materials Chemistry ,Lamellar structure ,Silicic acid - Abstract
International audience; It has been recently demonstrated that molecular and molecular cluster guest species can intercalate within lamellar stacks of purple membrane (PM), and be subsequently dried to produce functional bioinorganic nanocomposite films. However, the mechanism for the intercalation process remains to be fully understood. Here we employ surface X-ray scattering to study the intercalation of aminopropyl silicic acid (APS) or aminopropyl-functionalised magnesium phyllosilicate (AMP) molecular clusters into PM films. The composite films are prepared under aqueous conditions by guest infiltration into preformed PM films, or by co-assembly from an aqueous dispersion of PM sheets and guest molecules/clusters. Our results show that addition of an aqueous solution of guest molecules to a dried preformed PM film results in loss of the lamellar phase, and that subsequent air-drying induces re-stacking of the lipid/protein membrane sheets along with retention of a 2-3 nm hydration layer within the inter-lamellar spaces. We propose that this hydration layer is necessary for the intercalation of APS molecules or AMP oligomers into the PM film, and their subsequent condensation and retention as nano-thin inorganic lamellae within the composite mesostructure after drying. Our results indicate that the intercalated nanocomposites prepared from preformed PM films have a higher degree of ordering than those produced by co-assembly more...
- Published
- 2014
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