Phospholipid Morphologies on Photochemically Patterned Silane Monolayers
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- 作者：Michael C. Howland ; Annapoorna R. Sapuri-Butti ; Sanhita S. Dixit ; Andrew M. Dattelbaum ; Andrew P. Shreve ; and Atul N. Parikh
- 刊名：Journal of the American Chemical Society
- 出版年：2005
- 出版时间：May 11, 2005
- 年：2005
- 卷：127
- 期：18
- 页码：6752 - 6765
- 全文大小：1268K
- 年卷期：v.127,no.18(May 11, 2005)
- ISSN：1520-5126
文摘
We have studied the spreading of phospholipid vesicles on photochemically patternedn-octadecylsiloxane monolayers using epifluorescence and imaging ellipsometry measurements. Self-assembled monolayers of n-octadecylsiloxanes were patterned using short-wavelength ultraviolet radiationand a photomask to produce periodic arrays of patterned hydrophilic domains separated from hydrophobicsurroundings. Exposing these patterned surfaces to a solution of small unilamellar vesicles of phospholipidsand their mixtures resulted in a complex lipid layer morphology epitaxially reflecting the underlying patternof hydrophilicity. The hydrophilic square regions of the photopatterned OTS monolayer reflected lipid bilayerformation, and the hydrophobic OTS residues supported lipid monolayers. We further observed the existenceof a boundary region composed of a nonfluid lipid phase and a lipid-free moat at the interface between thelipid monolayer and bilayer morphologies spontaneously corralling the fluid bilayers. The outer-edge of theboundary region was found to be accessible for subsequent adsorption by proteins (e.g., streptavidin andBSA), but the inner-edge closer to the bilayer remained resistant to adsorption by protein or vesicles.Mechanistic implications of our results in terms of the effects of substrate topochemical character arediscussed. Furthermore, our results provide a basis for the construction of complex biomembrane models,which exhibit fluidity barriers and differentiate membrane properties based on correspondence betweenlipid leaflets. We also envisage the use of this construct where two-dimensionally fluid, low-defect lipidlayers serve as sacrificial resists for the deposition of protein and other material patterns.