Glycosaminoglycans incorporation on periodic block copolymer patterns for cell behaviour studies.

Cells are embedded in a complex meshwork of biomolecules known as extracellular matrix (ECM), whose composition, mechanical properties and nanoscale organization determine the cellular fate. Recent efforts are focused on understanding the role of each of these ECM properties as well as their synergistic effect on cellular adhesion, differentiation, growth and motility [1]. Glycosaminoglycans (GAGs), as major ECM components, are key elements involved in these processes: they interact with structural and signaling proteins via multiple interactions. In the pericellular space, GAGs are organized as arrays attached to proteins forming proteogylcans in the ECM or to the cell surface. The pattern and density of GAGs influence significantly their bioactivity as previously demonstrated by us and others [2, 3]. However, these are not easy to control especially when larger (e.g. centimeter) surface area are targeted.  

Herein, we describe patterns of self-assembled block copolymer (BC) that are used as templates for spatially controlled presentation of GAGs at the nanoscale. The developed platforms are useful for a range of applied and fundamental biological studies, screening the role of the GAGs and the patterns in cells fate. We chose polystyrene-block-poly-2-vinylpyridine (PS-b-2PVP) to create the nanopatterned templates because of its wide application in different self-assembly approaches and the possibility of following functionalization through electrostatic interactions via the PVP block [4]. The nanoscale patterns of PS-b-2PVP are formed upon structural reorganization of the BCs induced by treatments as thermal or solvent vapor annealing (SVA), i.e. the patterns can be controlled by the environmental conditions. We demonstrate that different patterns can be obtained as a result of SVA using different annealing time, annealing solvent or temperature. Furthermore, we were able to functionalize these nano-templates with hyaluronan. The utility of the obtained platforms is demonstrated in a study (cell adhesion and migration) with cancer cell lines overexpressing CD44 – a specific hyaluronan receptor.