P 24 ISSRNS 2012: Abstracts / Synchrotron Radiation in Natural Science Vol. 11, No 1 – 2 (2012)
INFLUENCE OF GEMINI SURFACTANTS WITH DIFFERENT CHAIN LENGTH ON THE STRUCTURE OF DPPC BILAYERS
W. Kida and M. Kozak∗
Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61–614 Pozna´n, Poland
Keywords: gemini surfactants, phospholipids, FTIR
∗e-mail : mkozak@amu.edu.pl
The miscibility properties of different lipids and formation of hydrated bilayer belong to fundamen- tal problems in biotechnology and biology. Phys- ical and functional properties of biomembranes are closely related to the miscibility of various kinds of lipids in them [1, 2]. Dipalmitoylphos- phatidylcholine (DPPC) belongs to phospholipids, which make a class of lipids and are major com- ponents of all cell membranes as they are able to form lipid bilayers. One of the major substances that can strongly interact with phospholipids and change their structural behavior are gemini surfac- tants. Gemini surfactants are characterised with dimeric architecture of molecules made of two hy- drophobic tails and two hydrophilic (polar) head groups [3, 4].
The study reported was undertaken to exami- nate the influence of quaternary alkyl-derivatives of bisimidazolium with different spacers and alkyl chain lengths at various concentrations on the struc- ture and phase stability of dipalmitoylphosphatidyl- choline in aqueous solutions.
The data presented were collected using CON- FOCHECK system. This system is based on FTIR Bruker spectrometer TENSOR 27 equipped with an AquaSpec micro transmission cell. The FTIR data were collected in the temperature range from 277 to 329 K using a HAAKE DL30 thermostat.
For each spectrum, 128 scans in the spectral range 4000 – 950 cm−1 were collected with the resolu- tion of 2 cm−1. The original FTIR spectra were smoothed using the Savitzky-Golay method.
The surfactants studied disturbed the lamellar phase typical of DPPC and finally, for the highest
surfactant concentration, the formation of unilamel- lar vesicles - bicelles. With increasing length of the acyl chain the temperature of the main phase tran- sition was shifted towards lower temperatures. The same effect was caused by increasing surfactant con- centration [5].
Acknowledgments: The study was supported by a research grant from the Ministry of Science and Higher Education (Grant No. N N204 135738).
References
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[2] M. Bloom, E. Evans, O.G. Mouritsen, “Physical properties of the fluid-bilayer component of cell membranes: A perspective,” Q. Rev. Biophys. 24 (1991) 293 – 297.
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