Abstract
We present experimental evidence for the existence of a unique molecular-level order in the vicinity of the bilayer's edge. Discrete patches of substrate-supported lipid bilayers exhibiting stable edge defects are prepared by confining vesicle fusion to hydrophilic patches of a chemically patterned substrate exhibiting hydrophilic patches in hydrophobic surrounding, and edge properties are characterized by fluorescence and vibrational spectroscopy based measurements. Specifically, wide-field fluorescence microscopy using phasesensitive dyes, temperature-programmed fluorescence recovery measurements, and temperature-dependent attenuated total reflection Fourier transform infrared spectroscopy measurements are performed to characterize the local chain conformational properties, local diffusional characteristics, and phase discrimination afforded by phase-sensitive DiI fluorescent probes. We find that the bilayer structure near the edge is characterized by (1) an increase in intramolecular conformational order; (2) reduced effective lateral mobility; and (3) a distinctly higher local, effective gel-fluid transition temperature in comparison to their bulk counterpart. Together, these features signal the emergence of unique ordering presumably triggered by the hemimicellar configuration of the edge. These results are consistent with simulations of lyso-lipid micelles predicting the presence of dynamic clusters of ordered lipids in comparable micellar topology and disagrees with some recent interpretations of mobility near the edges of supported bilayers. Our results also offer the structural basis for the stability of defects and edges in fluid supported bilayers, and may be relevant in understanding the ordering and stabilization of pores, edges, and defects generated in membrane bilayers by proteins, curvature-sensitive lipids, antimicrobial peptides, and detergents.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 9320-9327 |
| Number of pages | 8 |
| Journal | Journal of the American Chemical Society |
| Volume | 132 |
| Issue number | 27 |
| DOIs | |
| State | Published - Jul 14 2010 |
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ASJC Scopus subject areas
- Chemistry(all)
- Catalysis
- Biochemistry
- Colloid and Surface Chemistry
- Medicine(all)
Cite this
Order at the edge of the bilayer : Membrane remodeling at the edge of a planar supported bilayer is accompanied by a localized phase change. / Smith, Andreia M.; Vinchurkar, Madhuri; Gronbech-Jensen, Niels; Parikh, Atul N.
In: Journal of the American Chemical Society, Vol. 132, No. 27, 14.07.2010, p. 9320-9327.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Order at the edge of the bilayer
T2 - Membrane remodeling at the edge of a planar supported bilayer is accompanied by a localized phase change
AU - Smith, Andreia M.
AU - Vinchurkar, Madhuri
AU - Gronbech-Jensen, Niels
AU - Parikh, Atul N.
PY - 2010/7/14
Y1 - 2010/7/14
N2 - We present experimental evidence for the existence of a unique molecular-level order in the vicinity of the bilayer's edge. Discrete patches of substrate-supported lipid bilayers exhibiting stable edge defects are prepared by confining vesicle fusion to hydrophilic patches of a chemically patterned substrate exhibiting hydrophilic patches in hydrophobic surrounding, and edge properties are characterized by fluorescence and vibrational spectroscopy based measurements. Specifically, wide-field fluorescence microscopy using phasesensitive dyes, temperature-programmed fluorescence recovery measurements, and temperature-dependent attenuated total reflection Fourier transform infrared spectroscopy measurements are performed to characterize the local chain conformational properties, local diffusional characteristics, and phase discrimination afforded by phase-sensitive DiI fluorescent probes. We find that the bilayer structure near the edge is characterized by (1) an increase in intramolecular conformational order; (2) reduced effective lateral mobility; and (3) a distinctly higher local, effective gel-fluid transition temperature in comparison to their bulk counterpart. Together, these features signal the emergence of unique ordering presumably triggered by the hemimicellar configuration of the edge. These results are consistent with simulations of lyso-lipid micelles predicting the presence of dynamic clusters of ordered lipids in comparable micellar topology and disagrees with some recent interpretations of mobility near the edges of supported bilayers. Our results also offer the structural basis for the stability of defects and edges in fluid supported bilayers, and may be relevant in understanding the ordering and stabilization of pores, edges, and defects generated in membrane bilayers by proteins, curvature-sensitive lipids, antimicrobial peptides, and detergents.
AB - We present experimental evidence for the existence of a unique molecular-level order in the vicinity of the bilayer's edge. Discrete patches of substrate-supported lipid bilayers exhibiting stable edge defects are prepared by confining vesicle fusion to hydrophilic patches of a chemically patterned substrate exhibiting hydrophilic patches in hydrophobic surrounding, and edge properties are characterized by fluorescence and vibrational spectroscopy based measurements. Specifically, wide-field fluorescence microscopy using phasesensitive dyes, temperature-programmed fluorescence recovery measurements, and temperature-dependent attenuated total reflection Fourier transform infrared spectroscopy measurements are performed to characterize the local chain conformational properties, local diffusional characteristics, and phase discrimination afforded by phase-sensitive DiI fluorescent probes. We find that the bilayer structure near the edge is characterized by (1) an increase in intramolecular conformational order; (2) reduced effective lateral mobility; and (3) a distinctly higher local, effective gel-fluid transition temperature in comparison to their bulk counterpart. Together, these features signal the emergence of unique ordering presumably triggered by the hemimicellar configuration of the edge. These results are consistent with simulations of lyso-lipid micelles predicting the presence of dynamic clusters of ordered lipids in comparable micellar topology and disagrees with some recent interpretations of mobility near the edges of supported bilayers. Our results also offer the structural basis for the stability of defects and edges in fluid supported bilayers, and may be relevant in understanding the ordering and stabilization of pores, edges, and defects generated in membrane bilayers by proteins, curvature-sensitive lipids, antimicrobial peptides, and detergents.
UR - http://www.scopus.com/inward/record.url?scp=77955814961&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77955814961&partnerID=8YFLogxK
U2 - 10.1021/ja100294k
DO - 10.1021/ja100294k
M3 - Article
C2 - 20560661
AN - SCOPUS:77955814961
VL - 132
SP - 9320
EP - 9327
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 27
ER -