2022 Annual Meeting

(73e) The Discontinuous Surface of Porous Membranes Can be Engineered to Reduce Cell-Substrate Interactions Similarly to Soft Materials

Physiologically relevant in vitro tissue barrier and co-culture models are instrumental in investigating the mechanisms of drug delivery, leukocyte transmigration, cancer metastasis, and cell-cell communication during disease progression. Porous substrates are an indispensable part of many barrier model and tissue-on-chip platforms, but are largely treated as just another off-the-shelf component. Our laboratory has developed a variety of ultrathin and optically transparent nano- and micro-porous membranes to understand these systems' ideal properties better. We investigated engineering pore size and pore spacing to tune and control cell-substrate and cell-cell interactions. We found that reducing pore-pore spacing generally weakens cell-substrate interactions, as evidenced by fewer focal adhesions similarly to very soft substrates. On the other hand, endothelial cells on these same membranes have enhanced cell-cell interactions with more robust ZO-1 labeling, confirming a trade-off between cell-cell and cell-substrate interactions during monolayer formation. We further demonstrated that micron and submicron pore size influence early cell-substrate interaction and behavior in terms of migration and the associated extracellular matrix deposition and fibrillogenesis. Most recently, we investigated whether these disrupted surfaces affect yes-associated protein (YAP) localization and differentiation of adipose-derived stem cells. We found reduced YAP nuclear localization through decreased cell spreading, consistent with reduced cell–substrate interactions, and in turn enhanced adipogenesis and reduced osteogenesis. These results suggest that membrane parameters can be engineered for specific cell types and tissues to promote improved in vitrobarrier properties and potentially mimic softer more tissue-like substrates.