Berlin 2005 – scientific programme

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AKB: Biologische Physik

AKB 60: Membranes and Vesicles

AKB 60.5: Talk

Tuesday, March 8, 2005, 17:00–17:15, TU H2013

Chemical Switching of Diblock Copolymer Monolayers at the Interface: Controlling Interactions between Solid Substrates and Biological Matter — •Florian Rehfeldt¹, Kirstin Seidel¹, Roland Steitz², Regine v. Klitzing³, Steven P. Armes⁴, Alice P. Gast⁵, and Motomu Tanaka¹ — ¹Physik Dept. E22, TU München, James-Franck-Str., 85748 Garching, Germany — ²HMI Berlin GmbH, BENSC SF1, Glienicker Str. 100, 14109 Berlin, Germany — ³MPI f. Kolloid u. Grenzflächen, Golm, Germany — ⁴Dept. of Chemistry, Univ. of Sheffield, South Yorkshire S3 7HF, UK — ⁵Dept. of Chemical Engineering, M. I. T. Cambridge, MA 02139, USA

This study aims at the switching of interfacial interactions between soft, biological matter and planar solid substrates. As a switchable interlayer, a monolayer of (DMAEMA-b-MMA)is used. Specular neutron reflectivity experiments at solid/liquid interface demonstrated that the polymer chain conformation (thickness, hydration and surface roughness) can reversibly be switched in physiological environments due to charging and de-charging of the hydrophilic DMAEMA block. As next step, we carried out neutron reflectivity measurements of the polymer film with a supported lipid membrane. Upon pH titration between 5.5 and 8.5, we observe a clear switching in the membrane-substrate distance induced by the change in polymer chain conformation. The obtained results demonstrate that the diblock copolymer coating enables us to fine-tune the surface properties. The system established here suggests a great potential towards mimicking the extracellular matrix (ECM) to regulate the interfacial potential at substrate-membrane interface.