Milk sphingomyelin domains in biomimetic membranes and the role of cholesterol: Morphology and nanomechanical properties investigated using AFM and force spectroscopy

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DOIResolve DOI: http://doi.org/10.1021/la501640y
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TypeArticle
Journal titleLangmuir
ISSN1520-5827
Volume30
Issue22
Pages65166524; # of pages: 9
SubjectAtomic force microscopy; Biomimetics; Lipid bilayers; Mechanical properties; Morphology; Oils and fats; Phospholipids; Biomimetic membrane; Biophysical properties; Dioleoylphosphatidylcholine; Functional properties; Morphology and mechanical properties; Nanomechanical property; Structural and mechanical properties; Supported lipid bilayers; Cholesterol
AbstractMilk sphingomyelin (MSM) and cholesterol segregate into domains in the outer bilayer membrane surrounding milk fat globules. To elucidate the morphology and mechanical properties of theses domains, supported lipid bilayers with controlled molar proportions of MSM, dioleoylphosphatidylcholine (DOPC) and cholesterol were produced in buffer mimicking conditions of the milk aqueous phase. Atomic force microscopy imaging showed that (i) for T < 35 °C MSM segregated in gel phase domains protruding above the fluid phase, (ii) the addition of 20 mol % cholesterol resulted in smaller and more elongated l o phase domains than in equimolar MSM/DOPC membranes, (iii) the MSM/cholesterol-enriched lo phase domains were less salient than the MSM gel phase domains. Force spectroscopy measurements furthermore showed that cholesterol reduced the resistance of MSM/DOPC membrane to perforation. The results are discussed with respect to the effect of cholesterol on the biophysical properties of lipid membranes. The combination of AFM imaging and force mapping provides unprecedented insight into the structural and mechanical properties of milk lipid membranes, and opens perspectives for investigation of the functional properties of MSM domains during milk fat processing or digestion. © 2014 American Chemical Society.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); Measurement Science and Standards (MSS-SME)
Peer reviewedYes
NPARC number21272155
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Record identifieraad5e34d-77a3-469d-a3d9-fd7a9502613f
Record created2014-07-23
Record modified2016-05-09
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