ADDITIVE MICRO- AND NANOPATTERNING FOR THE FABRICATION OF BRAIN CELL NETWORKS

The challenges in creating cell cultures with controlled topology and in which cells maintain their in vivo-like phenotype are manifold. Engineering physiologically relevant brain cell networks requires the precise placement of cell bodies in an organized manner while providing the appropriate biophysical cues typical of the native extracellular matrix. In this work, an additive nanofabrication and micropatterning technique is employed to produce nanostructured substrates with complex micropatterns for cell culture aiming at this goal. The strength of this approach resides in the fact that the control on the nanoscale properties of the films, mimicking the native environment of the cells, is combined with the possibility to limit cell adhesion to predetermined substrate areas arranged in patterns. This enables the reproduction of in vitro cell networks with anatomically or functionally relevant geometrical shapes. This thesis provides the details of the method for the fabrication of nanostructured micropatterned films, analysing the advantages and limitations of the technique and providing solutions for obtaining stable and reproducible results. The nanostructured micropatterned substrates were used to characterize the combined effect of the nanoscale topography and cell confinement on astrocytic ensembles. The nanostructure is demonstrated to impact on proliferation, cell morphology, cytoskeletal structure, and calcium activity. It favours the development of astrocytes with morphological features like those found in vivo. Also, the micrometric architecture of the cultures was shown to affect cell morphology and behaviour. Calcium wave signaling was more effective in cells forming elongated clusters with dimension in the same range of blood vessels or axon fibers. The findings of this thesis provide novel insights on the mechanotransductive interaction between astrocytes and the nano- and micro-topographic cues of the cellular microenvironment, while highlighting the crucial role of the biophysical properties of the growth scaffolds to direct brain cell behaviour.