Since 2004 Professor for Biomedical Materials, Martin Luther University Halle-Wittenberg;
2003 Postdoctoral thesis (habilitation) at Institute of Biochemistry and Biology University of Potsdam;
2003 – 2004 Head of Department Biomaterials-Medical Technology at Institute of Chemistry of GKSS Research Centre (Helmholtz Society);
2001 – 2004 Coordinator of large scale project "Skin substitutes for clinical application” (BMBF);
1998 – 2002, Coordinator of large scale EU funded Brite/EuRam project "Membranes for biohybrid systems”,
1995 – 2002 Research Associate at Dept. Biomaterials Institute of Chemistry, GKSS Research Centre,
1991 PhD in Biophysics at Institute of Biophysics, Humboldt University Berlin,
1990 Visiting Scientist at Institute of Pathology of Technical University (RWTH) Aachen,
1987 – 1994 Assistant professor at Dept. Biomaterials,
1985 – 1987 Research Fellowship at Medical Faculty (Charité) of Humboldt University Berlin;
1985 Diploma thesis at Institute of Biophysics Humboldt University Berlin.
Published more than 100 papers in books and journals, more than 20 patents on biomaterials for apheresis, bioartificial organs, and tissue engineering, about 200 presentations at conferences.
Understanding biocompatibility of materials, development of biocompatible polymers and surfaces for blood contact and bioartificial organs, biomimetic surface modifications of materials for tissue engineering applications, characterization of cellular behavior on biomaterials.
His Topic of Materials' Days 2009:
Biomimetic Surface Treatment of Materials and its Influence on Cell Activity and Differentiation
Cell adhesion and spreading are important regulators of cell-biomaterial interaction, which control survival, growth and differentiation of cells. Here, we present a survey on our activities to apply a physical surface modification technique – the layer by layer technique, to obtain polyelectrolyte multilayers on model biomaterials to regulate adhesion, growth and differentiation of cells. The technique is based on the exploitation of electrostatic interaction between charged surfaces and polyelectrolytes in solutions. Multilayers were prepared with poly (ethylene imine) and chitosan (CHI) as polycations and gelatine (GEL), heparin (HEP), hyaluronic acid (HA) as polyanions. In a first part of the presentation we will show that changes of the pH value of polyelectrolyte solutions have a great impact multilayer formation process and ultimately on the surface properties of multilayers composed of HEP and CHI. As a consequence of changed surface properties, adhesion and growth of osteoblasts undergoes dramatic changes if the pH value is changed from pH 5 to 9. In further studies pH value was kept constant but multilayers composed of different pairs of polyelectrolytes such as CHI/GEL, CHI/HEP and CHI/HA were formed on polylactide films. These films had been first covalently modified with polyethylene imine to acquires strong positive surface charge. Physicochemical properties of multilayers were characterized by quartz microbalance, zeta potential and water contact angle measurements. Human mesenchymal stem cells (hMSC) were plated on the different multilayers and adhesion, growth and differentiation observed over three weeks. It was discovered that attachment and spreading of human mesenchymal stem cells (hMSC) was considerable high on CHI/GEL, moderate on CHI/HA and low on CHI/HEP. Investigation of hMSC after three weeks of culture revealed remarkable differences in morphology and differentiation showing that hMSC showed a strong osteogenic differentiation on on CHI/HEP or CHI/HA and a rather weak on CHI/GEL. Overall, biogenic multilayers represent a promising tool to obtain bioactive surface coatings on material surfaces to control adhesion, growth and differentiation of cells for a variety of biomedical and biotechnological applications.