SURF/SURG-Department of Biological Sciences - Carnegie Mellon University

Summer Undergraduate Research Fellowship (SURF) and Small Undergraduate Research Grants (SURG)

Sponsored by the Undergraduate Research Office (URO)

2012 SURF Recipients Participating in SURP

Robert Alberstein

Robert Alberstein, Carnegie Mellon University

Kelsey Hallinen

Kelsey Hallinen, Carnegie Mellon University

Volumetric Stability of Lipid Bilayers

In agreement with recent reports, a commercial densimeter has yielded a gradual decrease in lipid molecular volume of DPPC multilamellar vesicle dispersions in the gel phase upon repeated thermal cycling between 10ºC and 50ºC.  The considerable size of this decrease would have significant implications for the physical chemistry of biomembranes.  In contrast, neutral buoyancy measurements performed with similar thermal cycling indicate no gradual change in lipid volume in the gel phase at 20ºC.  Remixing the lipid in the densimeter shows that the apparent volume decrease is an artifact.  We conclude that gel phase DPPC bilayers exist in a volumetrically stable phase.

No Picture AvailableJonathan Michel, Carnegie Mellon University