UBC Theses and Dissertations
The effects of polymer-controlled hydration on nuclear magnetic resonance parameters Lees, Irene
The polymer polyethylene glycol (PEG) was used to control the amount of hydration in lipid bilayers. These bilayers were composed of either 1, 2-dimyristoyl-sn-glycero-3-phophocholine (DMPC) or 1, 2-dipalmitoyl-sn-glycero-3-phophocholine (DPPC) and oriented between glass slides. These lipids were deuterated in the head group to allow their study with 2H Nuclear Magnetic Resonance (NMR). Specifically, the quadrupolar splitting (Avg), the gel to liquid crystalline phase transition temperature (Tn,), the spin-lattice relaxation times and the spin-spin relaxation times were investigated as the membrane was dehydrated. Both Avg and Tn, are hydration dependent but no systematic change in the relaxation times was noted as a function of the water content of the sample. The spin-spin relaxation times did show an orientation dependence. The analysis led to the proposal that thickness fluctuations and thermal undulations of the membrane were two possible mechanisms for this relaxation.
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