Dresden 2006 – scientific programme
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AKB: Biologische Physik
AKB 40: Poster Session II
AKB 40.28: Poster
Wednesday, March 29, 2006, 16:30–19:30, P3
Highly oriented liquid water within the cationic lipid DODAB — •Lydia Woiterski1, Josef A. Käs1, David W. Britt2, and Carsten Selle1 — 1Institute of Experimental Physics I, University of Leipzig, Linnestraße 5, D-04103 Leipzig,Germany — 2Department of Bioengineering, University of Utah, Salt L ake City, UT , 84112, USA
Cationic lipid membranes spontaneously form complexes with DNA. Therefore, cationic synthetic lipids are widely used for the preparation of gene transfection systems.
We performed a fundamental attenuated total reflection (ATR) Fourier-Transform infrared (FTIR) spectroscopic study on the phase behavior and hydration properties of the cationic lipid dioctadecyldimethylammonium bromide (DODAB).
A unique shape of the ν(OH)-absorption band was detected that arises from liquid water in the vicinity of the polar lipid headgroup. Six subbands of the OH-absorption can be assigned to different populations of highly oriented water molecules. Furthermore, the spectroscopic properties of the headgroup bound water were observed to be strongly sensitive to the halide counterion present.
Another newly found feature of DODAB is a drastic change in the ν(CNC)-absorption which is attributed to a strong conformational alteration in one of the alkyl chains when the water is completely removed.