Berlin 2015 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

BP: Fachverband Biologische Physik

BP 46: Biomaterials and Biopolymers II (joint CPP/BP)

BP 46.9: Vortrag

Donnerstag, 19. März 2015, 17:15–17:30, C 264

Establishing Short-Range Gradients of Cytokines to Mimic Paracrine Cell Interactions in vitro — •Michael Ansorge and Tilo Pompe — Universität Leipzig, Institute of Biochemistry

Cells in various tissues receive myriads of exogenous signals, which in sum determine their fate. Many signaling molecules act in a gradient fashion to guide cell migration, differentiation and proliferation. We set up a microparticle-based system for generating biomimetic short-ranged gradients to analyze dynamic cell behavior with high resolution in vitro. The modification of agarose microbeads with glycosaminoglycans (GAG) with different degree of sulfation provides a toolbox to tune the binding and release of various cytokines.

Using chemically sulfated hyaluronic acid (HA) as GAG we were able to load the microbeads with different cytokines (SDF-1, TGF-beta, IL10) in dependence on their affinity to sulfated and non-sulfated HA. By following the local concentration decrease of fluorescently labeled cytokine inside the microbeads over days with confocal microscopy we could determine released amounts and diffusion-based transport properties. We were able to calculate local cytokine gradients surrounding the microbeads, which are estimated to be in the range of some tens of micrometers at physiological concentrations of pg/ml. We currently verify these local gradients using fluorescence correlation spectroscopy.

Studies on the dynamic cell behavior within the cytokines gradients address biomedical questions on cell fate of hematopoietic stem cells and fibroblasts in 3D collagen-based matrices.