Biomimetic cytoskeleton assemblies and living cells on micropillar force sensor arrays

Micropillar force sensor arrays are produced for biophysical studies of cellular and intracellular mechanics and for the assembly of suspended biofilament networks. Three types of pillars are made: (1) gold capped silicon pillars, (2) epoxy pillars and (3) polydimethylsiloxane (PDMS) pillars. Pillars with diameters of 1 - 5 µm and with a maximum aspect ratio (height : diameter) of 20 : 1 are produced. The pillar heads are selectively functionalised to allow the cultivation of fibroblasts, epithelial cells and heart muscle cells on their tops. Cellular traction forces are determined by measuring the bending of the pillar tops during cell movement. A model system for the actin cortex is produced by crosslinking actin filaments on the pillar heads, with the actin binding protein filamin. Crosslinking experiments are also conducted with divalent cations and with fluorescently labelled myosin II motors. The mechanical properties of single filaments are determined by Fourier analysis of their fluctuations. Transport properties of myosin V motors on the networks are quantified. Microtubule gliding assays in a three dimensional environment are conducted on the pillar tops by coating these with kinesin motors