We measure the elastic properties of composite cytoskeletal networks consisting of cross-linked actin filaments and microtubules. We show that even a small concentration of microtubules leads to dramatic and qualitative changes in the non-linear elastic properties of the actin filament networks. Specifically, we find that microtubules promote non-linear stiffening of F-actin networks because they are much stiffer than actin filaments and therefore suppress non-uniform strain. This finding may be relevant for interpretation of the mechanical behavior of cells, while also suggesting a new way to reinforce the non-linear elasticity of semiflexible polymer materials.

Soft Matter
Biological Soft Matter-Former Group

Lin, Y.-C., Koenderink, G., MacKintosh, F., & Weitz, D. A. (2011). Control of non-linear elasticity in F-actin networks with microtubules. Soft Matter, 7(3), 902–906. doi:10.1039/c0sm00478b