Type of Document	Master's Thesis
Author	Pinisetty, Dinesh
URN	etd-07142005-114202
Title	Molecular Dynamics Simulations of Biological Membranes in the Presence of Cryoprotectants
Degree	Master of Science in Mechanical Engineering (M.S.M.E.)
Department	Mechanical Engineering
Advisory Committee	Advisor Name Title Ram Devireddy Committee Chair Dorel Moldovan Committee Co-Chair Keith Gonthier Committee Member Su-Seng Pang Committee Member
Keywords	DPPC cryoprotectants MD simulations POPC DMPC
Date of Defense	2005-06-30
Availability	unrestricted
Abstract Cryopreservation is a process that is characterized by the transport of water and cryoprotectants through the cell membrane. This phenomenon has been studied in extensive detail at the macroscopic (µm) scale but in a somewhat more limited fashion at the microscopic (nm) scale. In this study we develop several lipid bilayer models to approximate a cell membrane (nm) and present the effect of several different cryoprotectants on the structural characteristics of these lipid bilayers using molecular dynamic simulations. The lipid bilayer models included dipalmitoylphosphatidylcholine (DPPC), dimyristoylphosphatidylcholine (DMPC) and palmitoyleylphosphatidylcholine (POPC) while the cryoprotectants included methanol and dimethylsulfoxide (DMSO). The molecular dynamic investigations suggests that the presence of methanol and DMSO has a significant effect on several structural properties of the lipid bilayers, including the area per lipid, mass density of nitrogen and phosphorus atoms in the lipid heads, water ordering near the bilayer and the radial distribution functions between several atoms in the lipid heads. Taken together, these results show that the presence of methanol and DMSO significantly decreases the bilayer thickness and suggests that the bilayers become more permeable to small molecules in their presence.
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