Fluid biomembranes supported on nanoporous aerogel/xerogel substrates.
Planar supported lipid bilayers have attracted immense interest for their properties as model cell membranes and for potential applications in biosensors and lab-on-a-chip devices. We report the formation of fluid planar biomembranes on hydrophilic silica aerogels and xerogels. Scanning electron microscopy results showed the presence of interconnected silica beads of approximately 10-25 nm in diameter and nanoscale open pores of comparable size for the aerogel and grain size of approximately 36-104 nm with approximately 9-24 nm diameter pores for the xerogel. When the aerogel/xerogel was prehydrated and then allowed to incubate in l-alpha-phosphatidylcholine (egg yolk PC) unilamellar vesicle (approximately 30 nm diameter) solution, lipid bilayers were formed due to the favorable interaction of vesicles with the hydroxyl-abundant silica surface. Lateral mobility of labeled lipid N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine was retained in the membranes. A diffusion coefficient of 0.61 +/- 0.22 microm(2)/s was determined from fluorescence recovery after photobleaching analysis for membranes on aerogels, compared to 2.46 +/- 0.35 microm(2)/s on flat glass. Quartz crystal microbalance-dissipation was utilized to monitor the kinetics of the irreversible adsorption and fusion of vesicles into bilayers on xerogel thin films.
Weng
Kevin C
KC
Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
Stålgren
Johan J R
JJ
Duval
David J
DJ
Risbud
Subhash H
SH
Frank
Curtis W
CW
D003460:Crystallization; D005782:Gels / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry; D008560:Membrane Fluidity; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D016062:Porosity; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors
D005782:Gels; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D012822:Silicon Dioxide