Lipid reassembly in asymmetric Langmuir-Blodgett/Langmuir-Schaeffer bilayers

  1. Get@NRC: Lipid reassembly in asymmetric Langmuir-Blodgett/Langmuir-Schaeffer bilayers (Opens in a new window)
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Journal titleLangmuir
Pages221227; # of pages: 7
Subject1 ,2-dioleoyl-sn-glycero-3-phosphocholine; AFM; Bi-layer; Binary lipid mixtures; Contrast changes; Domain structure; Dye molecule; Fluid-phase; Force mapping; Gel domains; Gel phase; Glass substrates; Image contrasts; Langmuir-blodgett; Lipid molecules; Multimodal imaging; Novel route; Phase segregations; Reassembly; Rupture forces; Single components; Solid-liquid interfaces; Structure dependent; Ternary mixtures; TIRF imaging; Total internal reflection fluorescence microscopy; Amino acids; Atomic force microscopy; Binary mixtures; Fluorescence; Mica; Molecules; Refractive index; Substrates; Lipid bilayers; aluminum silicate; glass; lipid; mica; article; atomic force microscopy; chemistry; lipid bilayer; Aluminum Silicates; Glass; Lipid Bilayers; Lipids; Microscopy, Atomic Force
AbstractMolecular-reorganization-induced morphology alteration in asymmetric substrate-supported lipid bilayers (SLBs) was directly visualized by means of atomic force microscopy (AFM) and total internal reflection fluorescence (TIRF) microscopy. SLB samples were fabricated on mica-on-glass and glass substrates by Langmuir-Blodgett (LB)/Langmuir-Schaeffer (LS) using binary lipid mixtures, namely, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn- glycero-3-phosphocholine (DPPC) and ternary mixtures DOPC/DPPC/1,2-dioleoyl-sn- glycero-3-phospho-l-serine (DOPS), labeled with 0.2 mol % Texas Red 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (TR-DHPE) dye. Phase segregations were characterized by TIRF imaging, and DPPC-enriched domain structures were also observed. Interestingly for ∼40% (n = 6) of the samples with binary mixtures in the LB leaflet and a single component in the LS leaflet, that is, (DOPC/DPPC)LB+DOPC LS, the contrast of the DPPC domains changed from the original dark (without dye) to bright (more TR dye partitioning) on TIRF images, returning to dark again. This contrast reverse was also correlated to AFM height images, where a DPPC-DPPC gel phase was spotted after the TIRF image contrast returned to dark. The rupture force mapping results measured on these binary mixture samples also confirmed unambiguously the formation of DPPC-DPPC gel domain components during the contrast change. The samples were tracked over 48 h to investigate the lipid molecule movements in both the DPPC domains and the DOPC fluid phase. The fluorescence contrast changes from bright to dark in SLBs indicate that the movement of dye molecules was independent of the movement of lipid molecules. In addition, correlated multimodal imaging using AFM, force mapping, and fluorescence provides a novel route to uncover the reorganization of lipid molecules at the solid-liquid interface, suggesting that the dynamics of dye molecules is highly structure dependent. © Published 2012 by the American Chemical Society.
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AffiliationNational Research Council Canada (NRC-CNRC)
Peer reviewedYes
NPARC number21270733
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Record identifier04c91300-11c2-4777-a6b6-5e96bb9dd9f2
Record created2014-02-17
Record modified2016-05-09
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