Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.14.289330v1?rss=1 Authors: Vinje, J., Guadagno, N. A., Progida, C., Sikorski, P. Abstract: Cells in their natural environment are embedded in a complex surrounding consisting of biochemical and biomechanical cues directing cell properties and cell behaviour. Nonetheless, in vitro cell studies are typically performed on flat surfaces, with clear differences from the more complex situation cells experience in vivo. To increase the physiological relevance of these studies, a number of advanced cellular substrates for in vitro studies have been applied. One of these approaches include flat surfaces decorated with vertically aligned nanostructures. In this work, we explore how U2OS cells are affected by arrays of polymer nanopillars fabricated on flat glass surfaces. We focus on describing changes to the organisation of the actin cytoskeleton and in the location, number and shape of focal adhesions. From our findings we identify that the cells can be categorised into different regimes based on their spreading and adhesion behaviour on nanopillars. A quantitative analysis suggests that cells seeded on dense nanopillar arrays are suspended on top of the pillars with focal adhesions forming closer to the cell periphery compared to flat surfaces or sparse pillar arrays. Copy rights belong to original authors. Visit the link for more info