Surface-Attached Hydrogel Layer Systems

Hydrogel materials made of water-swollen polymer networks possess a large number of specific properties that render them attractive for a variety of biomedical applications. A particular class of these systems are responsive hydrogels that can change their swelling state due to changes of environmental parameters, like temperature or salt concentration. All this property renders these materials highly attractive for sensors, actuators, adhesives, and coatings. In this project new polymer systems are synthesized, which can be crosslinked by irradiation with light to form hydrogel materials with tailored properties. The photocrosslinking procedure allows full control over the crosslink density (via the irradiation time) and provides the means of lithographic patterning by masked irradiation (specifically of thin hydrogel films). The polymer network can further be modified by chemical reactions, for example, with biologically active ligands for specific binding of a target in biomedical uses.

For the preparation of surface-attached hydrogel films (see scheme below) the substrate is first modified with an adhesion promoter, which in our case can also be activated by light. Then a thin polymer film is deposited from solution onto the modified substrate. After drying the polymer layer is irradiated to introduce crosslinks and simultaneously form covalent bonds with the adhesion promoter to anchor the polymer network permanently to the substrate. Subsequent chemical modification is performed on the surface-attached networks according to the specific needs.

The properties and structure of such films are investigated in detail with spectroscopic and microscopic techniques (like surface plasmon resonance / optical waveguide spectroscopy or scanning force microscopy).

Collaboration Partners:

Dr. Jakub Dostalek & Prof. Dr. Wolfgang Knoll - AIT-Austrian Institute of Technology, BioSensor Technologies, Muthgasse 11/2, 1190 Vienna, Austria

Prof. Dr. Georg Fytas - Foundation for Research and Technology Hellas (FORTH), Institute of Electronic Structure & Laser (IESL), P.O. Box 1527, 71110 Heraklion, Greece - and - Department of Materials Science and Technology, University of Crete, Heraklion, Greece - and - Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

Dr. Ulrike Ritz - Universitätsmedizin der Johannes Gutenberg-Universität Mainz, Wissenschaftliches Labor des Zentrums für Orthopädie und Unfallchirurgie, Mainz, Germany

Prof. Dr. Maria Chatzinikolaidou - Department of Material Science and Technology, University of Crete, Greece

Dr. med. Lars Choritz - Universitätsklinikum Magdeburg A.ö.R., Forschungslabor der Augenklinik, Magdeburg, Germany

Dr. Manolis Stiakakis -Forschungszentrum Juelich GmbH, Juelich, Germany