Dresden 2009 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 3: Focus: Amphiphilic systems III
CPP 3.2: Talk
Monday, March 23, 2009, 18:30–18:45, ZEU 222
Responsive Polymer Cushions for Lipid Bilayer Manipulation — •Martin Kaufmann1, Dirk Kuckling2, Carsten Werner1, and Tilo Pompe1 — 1Leibniz Institute for Polymer Research, Dresden, Germany — 2University of Paderborn, Department of Chemistry, Germany
Supported lipid bilayer membranes (sLBM) are used to study the function of membranes of living cells. We introduce a pH- and thermoresponsive polymer cushion platform which allows for a switching of the interaction of the sLBM and incorporated transmembrane biomolecules with the solid support. Copolymers composed of N-isopropylacrylamide (NiPAAm) and varying amounts of acrylamide derivatives bearing carboxylic groups at different spacer length were immobilized as thin films and characterized by quartz crystal microbalance. Cushion thickness could be switched between 15–150 nm in response to changes in pH and temperature with lower critical solution temperatures in biological relevant ranges of 15–45 ∘C. sLBM were successfully formed from a lipid mixture composed of 90 % DOPC and 10 % DOTAP. First sLBM mobility measurements using fluorescence recovery after photobleaching revealed diffusion coefficients on swollen copolymer films (8.0 m2s−1) distinctly higher than on SiO2 sLBM (6.0 m2s−1). This finding proposes a reduced friction between lipids and the copolymer cushion in comparison to SiO2. The copolymer cushion responsiveness will be used to further adjust lipid-support interaction and to vary the characteristics of incorporated transmembrane proteins.