TY - JOUR
T1 - Correlated AFM and NanoSIMS imaging to probe cholesterol-induced changes in phase behavior and non-ideal mixing in ternary lipid membranes
AU - Anderton, Christopher R.
AU - Lou, Kaiyan
AU - Weber, Peter K.
AU - Hutcheon, Ian D.
AU - Kraft, Mary L.
N1 - Funding Information:
We thank S. MacLaren for the helpful discussions on AFM, W. Hanafin for the assistance with the assays, S. Boxer for the oxidized silicon substrates, C. Ramon for the technical assistance, and L. Nittler for the software development. MLK holds a Career Award at the Scientific Interface from the Burroughs Wellcome Fund. Portions of this work were carried out in the Frederick Seitz Materials Research Laboratory Central Facilities, Univ. of Illinois, which are partially supported by the U.S. Department of Energy (DOE) under grants DE-FG02-07ER46453 and DE-FG02-07ER46471 . Work at LLNL was supported by the Laboratory Directed Research and Development funding and performed under the auspices of the U.S. DOE under contract DE-AC52-07NA27344 .
PY - 2011/1
Y1 - 2011/1
N2 - Cholesterol is believed to be an important component in compositionally distinct lipid domains in the cellular plasma membrane, which are referred to as lipid rafts. Insight into how cholesterol influences the interactions that contribute to plasma membrane organization can be acquired from model lipid membranes. Here we characterize the lipid mixing and phase behavior exhibited by 15N-dilaurolyphosphatidycholine (15N-DLPC)/deuterated distearoylphosphatiylcholine (D70-DSPC) membranes with various amounts of cholesterol (0, 3, 7, 15 or 19 mol%) at room temperature. The microstructures and compositions of individual membrane domains were determined by imaging the same membrane locations with both atomic force microscopy (AFM) and high-resolution secondary ion mass spectrometry (SIMS) performed with a Cameca NanoSIMS 50. As the cholesterol composition increased from 0 to 19 mol%, the circular ordered domains became more elongated, and the amount of 15N-DLPC in the gel-phase domains remained constant at 6-7 mol%. Individual and micron-sized clusters of nanoscopic domains enriched in D 70-DSPC were abundant in the 19 mol% cholesterol membrane. AFM imaging showed that these lipid domains had irregular borders, indicating that they were gel-phase domains, and not non-ideally mixed lipid clusters or nanoscopic liquid-ordered domains.
AB - Cholesterol is believed to be an important component in compositionally distinct lipid domains in the cellular plasma membrane, which are referred to as lipid rafts. Insight into how cholesterol influences the interactions that contribute to plasma membrane organization can be acquired from model lipid membranes. Here we characterize the lipid mixing and phase behavior exhibited by 15N-dilaurolyphosphatidycholine (15N-DLPC)/deuterated distearoylphosphatiylcholine (D70-DSPC) membranes with various amounts of cholesterol (0, 3, 7, 15 or 19 mol%) at room temperature. The microstructures and compositions of individual membrane domains were determined by imaging the same membrane locations with both atomic force microscopy (AFM) and high-resolution secondary ion mass spectrometry (SIMS) performed with a Cameca NanoSIMS 50. As the cholesterol composition increased from 0 to 19 mol%, the circular ordered domains became more elongated, and the amount of 15N-DLPC in the gel-phase domains remained constant at 6-7 mol%. Individual and micron-sized clusters of nanoscopic domains enriched in D 70-DSPC were abundant in the 19 mol% cholesterol membrane. AFM imaging showed that these lipid domains had irregular borders, indicating that they were gel-phase domains, and not non-ideally mixed lipid clusters or nanoscopic liquid-ordered domains.
KW - Atomic force microscopy
KW - Cholesterol
KW - Lipid composition
KW - Lipid phase behavior
KW - Phase separation
KW - Secondary ion mass spectrometry
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U2 - 10.1016/j.bbamem.2010.09.016
DO - 10.1016/j.bbamem.2010.09.016
M3 - Article
C2 - 20883665
AN - SCOPUS:78649770037
SN - 0005-2736
VL - 1808
SP - 307
EP - 315
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
IS - 1
ER -