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.
Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
Kevin C
KC
Weng
Johan J R
JJ
Stålgren
David J
DJ
Duval
Subhash H
SH
Risbud
Curtis W
CW
Frank
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