Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 20: POSTER A

CPP 20.34: Poster

Montag, 24. März 2003, 19:00–21:00, ZEU/250

Chemical switching of protein-surface interaction using weak polyelectrolyte brushes — •Florian Rehfeldt¹, Roland Steitz², Regine v. Klitzing², and Motomu Tanaka¹ — ¹TU München, Physik Department E22, Lehrstuhl für Biophysik, James-Franck-Str., D-85747 Garching — ²Stranski-Laboratorium, TU Berlin, Straße d. 17. Juni 112, D-10623 Berlin

The switching of physical properties of thin polymer films (charge density, chain conformation, viscoelasticity, etc.) under physiological conditions (neutral pH, ionic strength 50 - 500 mM) draws increasing attention to control cell-surface/protein-surface interaction by means of external stimulation. For this purpose, one of the attractive candidates is a relatively No-dqweakNo-dq polyelectrolyte, whose degree of ionisation (D.I.) can be controlled by pH titration. We chose a diblock-copolymer that possesses a hydrophobic MMA block and a hydrophilic DMAEMA block. The D.I. of DMAEMA block is 0.6 at pH = 5.5, and 0.2 at pH=8.5, respectively. When the block ratio is 1:1, this type of diblock forms an insoluble monolayer at air/water interface. Recently, we demonstrated the adsorption and desorption of weakly charged DMAEMA chains at air/water interface by pH titration. Such insoluble monolayers can be transferred from air/water interface onto hydrophobized silicon blocks, where changes in the layer thickness as well as in the scattering length density can be monitored with neutron reflectivity. Furthermore, adsorption of water-soluble proteins on charged- and uncharged brushes is currently studied.