BPCPPDYSOE21 – scientific programme

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BP: Fachverband Biologische Physik

BP 11: Poster A: Single Molecule, Multicellular, Bioimaging, Focus Sessions, etc.

BP 11.3: Poster

Monday, March 22, 2021, 16:30–19:00, BPp

The mechanics of single cross-links which mediate cell attachment at a hydrogel surface — Arzu Colak, Bin Li, Johanna Blass, Aranzazu del Campo, and •Roland Bennewitz — INM - Leibniz Institute for New Materials, Saarbrücken, Germany

Cells attach to the surface of a poly(ethylene glycol diacrylate) (PEGDA) hydrogel if linkers are functionalized with the RGD cell adhesive motif. Attachment and spreading of cells on the hydrogel depend on its mechanical properties, for examples when Young*s modulus E of the hydrogel is varied. We were interested in the effective stiffness of those linkers which mediate cell attachment and measured it by means of single-molecule force spectroscopy [1]. For these experiments, the linkers were functionalized with biotin and the tip of an atomic force microscope with streptavidin. A factor of ten in the elastic modulus E of the hydrogel corresponded to a factor of five in the effective spring constant k of single crosslinks, indicating a transition in scaling with the mesh size ζ from the macroscopic E∝ζ⁻³ to the molecular k∝ζ⁻². The effective stiffness of single linkers was also measured for a second polymer network based on four-arm star-PEG molecules which interpenetrated the PEGDA hydrogel. The quantification of stiffness and deformation at the molecular length scale contributes to the discussion of mechanisms in force-regulated phenomena in cell biology. [1] A. Colak, B. Li, J. Blass, K. Koynov, A. del Campo, R. Bennewitz, The mechanics of single cross-links which mediate cell attachment at a hydrogel surface, Nanoscale, 11 (2019) 11596-11604.