Regensburg 2016 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 50: Posters - Cell Adhesion

BP 50.3: Poster

Mittwoch, 9. März 2016, 17:00–19:00, Poster C

Substrate elasticity and ligand affinity affect traction force evolution — •Christina Müller and Tilo Pompe — Institute of Biochemistry, Universität Leipzig, Germany

Mechanotransduction is known as one control mechanism for several basic cell functions, like proliferation, differentiation and cell death. We investigated early cell adhesion on hydrogels with an independent variation of substrate stiffness and affinity of the adhesion ligand fibronectin to the hydrogel surface. Thin film coatings of maleic acid copolymers on top of polyacrylamide hydrogel layers were fabricated to tune protein binding. The Young's modulus of the hydrogel was modulated between 2.5 kPa and 9 kPa. Human umbilical vein endothelial cells were monitored during the first two hours of cell adhesion by time-resolved cell traction force microscopy. Three different regimes of traction force generation were found. In the first regime (R0) cells spread fast, but traction forces were negligibly small. Regime R1 is characterized by a decelerated spreading and a succeeding force increase. After completion of spreading cells enter regime R2 with saturated forces. Substrate stiffness ligand and affinity were both found to affect the kinetics and absolute levels of traction force quantities. A faster increase and a higher saturation level of traction forces were observed for a higher substrate stiffness and a higher ligand affinity. The results show that cells perform varying proportions of work against conservative and dissipative forces. Finally, our findings complement recent modeling approaches and contribute to a better understanding of the dynamics of cell adhesion on viscoelastic substrates.