Membrane Pore Spacing Can Modulate Endothelial Cell–Substrate and Cell–Cell Interactions

Mechanical cues and substrate interaction affect the manner in which cells adhere, spread, migrate and form tissues. With increased interest in tissue-on-a-chip and co-culture systems utilizing porous membranes, it is important to understand the role of disrupted surfaces on cellular behavior. Using a transparent glass membrane with defined pore geometries, we investigated endothelial fibronectin fibrillogenesis and formation of focal adhesions as well as development of intercellular junctions. Cells formed fewer focal adhesions and had shorter fibronectin fibrils on porous membranes compared to non-porous controls, which was similar to cell behavior on continuous soft substrates with Young's moduli seven orders of magnitude lower than glass. Additionally, porous membranes promoted enhanced cell-cell interactions as evidenced by earlier formation of tight junctions. These findings suggest that porous membranes with discontinuous surfaces promote reduced cell-matrix interactions similarly to soft substrates and may enhance tissue and barrier formation.