Pathways of lipid vesicle deposition on solid surfaces: a combined QCM-D and AFM study.
Supported lipid bilayers (SLBs) are popular models of cell membranes with potential biotechnological applications, yet the mechanism of SLB formation is only partially understood. In this study, the adsorption and subsequent conformational changes of sonicated unilamellar vesicles on silica supports were investigated by quartz crystal microbalance with dissipation monitoring and atomic force microscopy, using mixtures of zwitterionic, negatively charged, and positively charged lipids, both in the presence and in the absence of Ca(2+) ions. Four different pathways of vesicle deposition could be distinguished. Depending on their charge, vesicles i). did not adsorb; ii). formed a stable vesicular layer; or iii). decomposed into an SLB after adsorption at high critical coverage or iv). at low coverage. Calcium was shown to enhance the tendency of SLB formation for negatively charged and zwitterionic vesicles. The role of vesicle-support, interbilayer, and intrabilayer interactions in the formation of SLBs is discussed.
Laboratoire d'Imagerie Moléculaire et Nano-Bio-Technologie, Institut Europeen de Chimie et Biologie, Université Bordeaux 1, 33607 Pessac Cedex, France.
Ralf
R
Richter
Anneke
A
Mukhopadhyay
Alain
A
Brisson
D000327:Adsorption; D002118:Calcium / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry*; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry; D008051:Lipid Bilayers / Q000138:chemical synthesis / Q000737:chemistry*; D008081:Liposomes / Q000138:chemical synthesis / Q000737:chemistry*; D046911:Macromolecular Substances; D008560:Membrane Fluidity; D008561:Membrane Fusion; D018625:Microscopy, Atomic Force / Q000379:methods*; D008968:Molecular Conformation; D010713:Phosphatidylcholines / Q000737:chemistry; D010718:Phosphatidylserines / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013499:Surface Properties; D014159:Transducers
D005229:Fatty Acids, Monounsaturated; D008051:Lipid Bilayers; D008081:Liposomes; D046911:Macromolecular Substances; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D000644:Quaternary Ammonium Compounds; C042511:1,2-dioleoylphosphatidylserine; D004492:Edetic Acid; C017251:1,2-oleoylphosphatidylcholine; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane; D002118:Calcium