title: Layer-by-Layer Assembly of Supported Lipid Bilayer Poly-L-Lysine Multilayers.
abstract: Multilayer lipid membranes perform many important functions in biology, such as electrical isolation (myelination of axons), increased surface area for biocatalytic purposes (thylakoid grana and mitochondrial cristae), and sequential processing (golgi cisternae). Here we develop a simple layer-by-layer methodology to form lipid multilayers via vesicle rupture onto existing supported lipid bilayers (SLBs) using poly l-lysine (PLL) as an electrostatic polymer linker. The assembly process was monitored at the macroscale by quartz crystal microbalance with dissipation (QCM-D) and the nanoscale by atomic force microscopy (AFM) for up to six lipid bilayers. By varying buffer pH and PLL chain length, we show that longer chains (≥300 kDa) at pH 9.0 form thicker polymer supported multilayers, while at low pH and shorter length PLL, we create close packed layers (average lipid bilayers separations of 2.8 and 0.8 nm, respectively). Fluorescence recovery after photobleaching (FRAP) and AFM were used to show that the diffusion of lipid and three different membrane proteins in the multilayered membranes has little dependence on lipid stack number or separation between membranes. These approaches provide a straightforward route to creating the complex membrane structures that are found throughout nature, allowing possible applications in areas such as energy production and biosensing while developing our understanding of the biological processes at play.
authors.affiliation: School of Biomedical Sciences, University of Leeds , Leeds LS2 9JT, United Kingdom.
authors.forename: George R
authors.initials: GR
authors.lastname: Heath
authors.affiliation: School of Biomedical Sciences, University of Leeds , Leeds LS2 9JT, United Kingdom.
authors.forename: Mengqiu
authors.initials: M
authors.lastname: Li
authors.affiliation: Life Sciences and Systems Biology, University of Torino , 10123, Turin, Italy.
authors.forename: Isabelle L
authors.initials: IL
authors.lastname: Polignano
authors.affiliation: Cell Biophysics Group, Institute of Biophysics, Imaging and Optical Science, School of Life Sciences, University of Nottingham , Nottingham, NG7 2RD, United Kingdom.
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Richens
authors.affiliation: Life Sciences and Systems Biology, University of Torino , 10123, Turin, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Catucci
authors.affiliation: Cell Biophysics Group, Institute of Biophysics, Imaging and Optical Science, School of Life Sciences, University of Nottingham , Nottingham, NG7 2RD, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: O'Shea
authors.affiliation: Life Sciences and Systems Biology, University of Torino , 10123, Turin, Italy.
authors.forename: Sheila J
authors.initials: SJ
authors.lastname: Sadeghi
authors.affiliation: Life Sciences and Systems Biology, University of Torino , 10123, Turin, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Gilardi
authors.affiliation: Centre for Molecular and Structural Biochemistry, School of Biological Sciences, and School of Chemistry, University of East Anglia , Norwich NR4 7TJ, United Kingdom.
authors.forename: Julea N
authors.initials: JN
authors.lastname: Butt
authors.affiliation: School of Biomedical Sciences, University of Leeds , Leeds LS2 9JT, United Kingdom.
authors.forename: Lars J C
authors.initials: LJ
authors.lastname: Jeuken
mesh_terms: D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000138:chemical synthesis*; D008566:Membranes / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D011107:Polylysine / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis; D058525:Quartz Crystal Microbalance Techniques; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes; D011108:Polymers; D011107:Polylysine