Giam, L.R. et al. Proc. Natl. Acad. Sci. USA 109, 4377–4382 (2012).

There is much interest in understanding the role of substrate topology on the mechanical properties of cells and its possible biological consequences. Methods to study cell-substrate interactions are thus in demand. In recent work, Giam et al. describe the use of massively parallel polymer pen lithography to generate substrates with customized patterns. The pen arrays can be used either in a level or a tilted configuration, the latter enabling the rapid preparation of combinatorial libraries with topological features that range in scale from microscale to nanoscale. The researchers used these tilted arrays to generate gridded fibronectin patterns of varying size and spacing. They observed differences in the amounts of osteogenic markers in mesenchymal stem cells plated on nanoscale- versus microscale-patterned fibronectin.