Dresden 2009 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 2: Focus: Amphiphilic Systems II

CPP 2.6: Vortrag

Montag, 23. März 2009, 16:15–16:30, ZEU 222

Pressure Jump Relaxation Investigations of Lipid Bilayers Using FTIR Spectroscopy — •Martin Schiewek and Alfred Blume — Martin-Luther-Universität Halle-Wittenberg, Institut für Chemie, Mühlpforte 1, 06108 Halle(Saale)

The relaxation kinetics of aqueous lipid dispersions after a pressure jump (p-jump) were investigated using time-resolved FTIR spectroscopy with a time resolution of ca. 10 ms. The methylene stretching vibrational bands and the carbonyl band were analyzed to detect changes in conformational order of the hydrocarbon chains and to follow the degree of hydration of the head group, respectively. The kinetics of the transition was found to consist of multiple processes with relaxation constants from seconds down to milliseconds. Faster processes are also present, but could not be resolved by our instrument.

This is the first investigation showing directly the time resolved change in chain order in lipid bilayers induced by a pressure jump using IR spectroscopy. The results obtained with this IR detection method support previous results obtained with light scattering and fluorescence techniques that the change in chain order after a perturbation is a multi-step process with the initial molecular events occurring with time constants shorter than milliseconds.