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Research Abstracts Online
January 2008 - March 2009

University of Minnesota Twin Cities
Institute of Technology
Department of Mechanical Engineering

PI: Alptekin Aksan
Co-PI: Jonathan N. Sachs, Associate Fellow

Effect of Hyperosmotic Stress on the Structure of a Lipid Bilayer

The aim of this study is to investigate the response of the membrane to hyperosmotic stress, which is experienced by cells during cryopreservation. Experimental evidence has revealed that both the extent and rate of dehydration, which are related to the trans-membrane water concentration, play a role in the final membrane structure. Molecular dynamics (MD) simulations will be used to test the hypothesis that the large chemical potential gradient, responsible for the hyperosmotic stress, causes membrane structural changes. The simulations will consist of all-atom and coarse-grained simulations of a water concentration gradient across a lipid bilayer. A unit cell containing two lipid bilayers separated by osmolyte-water baths will be used to create the concentration gradient while still allowing the use of periodic boundary conditions. The full-atom simulations will provide information on changes on the bilayer over shorter timescales (~ nanoseconds) and also provide a basis for comparison for the coarse-grained model. The coarse-grained MD simulation will probe changes in the bilayer structure over longer timescales (~ microseconds).

Group Member

Vishard Ragoonanan, Graduate Student