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January 2009 - March 2010

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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 the rate of dehydration, which is a function of the trans-membrane water concentration, plays a role in the final membrane structure. The first step in understanding the resultant structural changes due to osmotic driven water flow is to investigate the molecular-level events related to water transport across the membrane. 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 a lipid bilayer through which water will be "forced.” The water will be forced by using an additional directed force to water molecules located near one side of the bilayer. The full-atom simulations will provide information on changes on the bilayer over shorter timescales (~ns) 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 (~μs).

Group Member

Vishard Ragoonanan, Graduate Student