Biointerphases

Journal for Biophysical Chemistry

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Open Access

Lateral heterogeneities in supported bilayers from pure and mixed phosphatidylethanolamine demonstrating hydrogen bonding capacity

  • Matthew R. Nussio1,
  • Nicolas H. Voelcker1Email author,
  • Matthew J. Sykes2,
  • Steven J. P. McInnes1,
  • Christopher T. Gibson1,
  • Rachel D. Lowe1,
  • John O. Miners2 and
  • Joseph G. Shapter1Email author
Biointerphases3:30400096

https://doi.org/10.1116/1.3040158

Received: 19 September 2008

Accepted: 6 November 2008

Abstract

The phase behavior and lateral organization of saturated phosphatidylethanolamine (PE) and phosphatidylcholine (PC) bilayers were investigated using atomic force microscopy (AFM) and force-volume (FV) imaging for both pure and two component mixed layers. The results demonstrated the existence of unexpected segregated domains in pure PE membranes at temperatures well below the transition temperature (T m ) of the component phospholipid. These domains were of low mechanical stability and lacked the capacity for hydrogen bonding between lipid headgroups. Temperature dependent studies for different PC/PE ratios using AFM also demonstrated the mixing of these phospholipid bilayers to exhibit only a single gel to liquid transition temperature. Further work performed using FV imaging and chemically modified probes established that no lipid segregation exists at the PC/PE ratios investigated.