Lipid membranes

One of our group’s main research interests has been in the structure and phase behavior of lipid membranes. The cell membrane is a selectively permeable barrier  between the cell and its external environment and consists of a lipid bilayer. Lipid membranes are an example of  a self-assembling soft material exhibit a rich phase behavior.  Our group is interested in applying our studies of membrane structure to addressing questions form cell biology and developing new bioinspired materials.

Group members taking part in an x-ray diffraction experiment at Brookhaven national laboratory








Some recent projects from the lab include:

  • Phase separation and fluorescence induced domain formation in ternary lipid membranes.

“Phase behavior and critical phenomena in ternary lipid mixtures” L.S. Hirst, P. Uppamoochikkal and C. Lor, LIQUID CRYSTALS,Vol. 38, 11-12, 1735-1747(2011) Link

“Solution synchrotron x-ray diffraction reveals structural details of lipid domains in ternary mixtures” J. Yuan, A. Kiss, Y.H. Pramudya, L.T. Nguyen and L.S. Hirst, PHYS. REV. E. 79 (3) 031924 (2009) Link

“The effects of fluorescent probes on model membrane organization: Photo-induced lipid Sorting and Soft Structure Formation” L.S. Hirst and J. Yuan, LIQUID CRYSTALS ,36, 6, 739 ( 2009) Link

“Lipid Bilayer Discs and Banded Tubules: Photo-induced Lipid Sorting in Ternary Mixtures” J. Yuan, S. Hira, G. Strouse and L.S. Hirst, J. AM. CHEM. SOC. 130 (6), 2067 -2072, 2008, Link

  • The role of topological defects in lipid vesicle morphologies.

“Morphology transition in lipid vesicles due to in-plane order and topological defects” L.S. Hirst, A. Ossowski, M. Fraser, J. Geng, J.V. Selinger and R.L.B. Selinger, PROC. NATL. ACAD. SCI. 110 (9) 3242-3247 (2013) Link

  • Mechanical properties of lipid vesicles using a dual beam optical trap

“Fiber-optic trap-on-a-chip platform for probing low refractive index contrast biomaterials” T.M. Pinon, A. Castelli, L.S. Hirst and J.E. Sharping, APPLIED OPTICS,52 (11), 2340 – 2345 (2013) Link

“Stability of dual-beam fiber-optical traps for low refractive index contrast particles” J. E. Sharping, T.M. Pinon and L.S. Hirst, CLEO: Applications and Technology, OSA Technical Digest, Optical Society of America, (2013)Link

Our latest project in this field is a collaboration with Prof Jing Xu at UC Merced in which we are looking at the role of membrane cargo composition on intracellular transport via kinesin motors.


A complete listing of the group’s publications can be found here.




Soft Matter and biophysics at the University of California, Merced