Lipid domain morphologies in phosphatidylcholine-ceramide monolayers

Mikko Karttunen, Mikko P. Haataja, Matti Saily, Ilpo Vattulainen, Juha M. Holopainenr

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

In cells, one of the main roles of ceramide-enriched membrane domains is to recruit or exclude intracellular signaling molecules and receptors, thereby facilitating signal transduction cascades. Accordingly, in model membranes, even low contents of ceramide segregate into lateral domains. The impact of the N-acyl chain on this segregation and on the morphology of the domains remains to be explored. Using Langmuir monolayers, we have systematically studied binary mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and ceramide (2:1, molar ratio) and varied the N-acyl chain length of ceramide from 2 to 24 carbon atoms (Cer 2 to Cer 24). Fluid Cer 2, Cer 6, and Cer 8/DMPC mixtures were miscible at all surface pressures. Longer ceramides, however, formed surface pressure-dependent immiscible mixtures with DMPC. The domain morphology under fluorescence microscopy after including a trace amount of fluorescent NBD-phosphatidylcholine into DMPC/Cer mixtures was found to be very sensitive to the N-acyl chain length. Shorter ceramides (Cer 10-Cer 14) formed flower-like (seaweed) domains, whereas longer ceramides (N-acyl chain length > 14 carbon atoms) formed round and regular domains. We attribute the formation of the flower patterns to diffusive morphological instabilities during domain growth.

Original languageEnglish (US)
Pages (from-to)4595-4600
Number of pages6
JournalLangmuir
Volume25
Issue number8
DOIs
StatePublished - Apr 21 2009

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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