Renal Epithelial Cell Responses to Supramolecular Thermoplastic Elastomeric Concave and Convex Structures

The nephron naturally provides a concave conformation for epithelial cells, yet biomedical applications such as bioartificial kidney can employ convex seeding. Frequently glass or polydimethylsiloxane are utilized as base materials to study renal epithelial cell response to curvatures. Insights on relevant materials for biomedical applications remain limited. Here it is investigated how human immortalized renal proximal tubule epithelial cells (RPTEC) respond to a range of concave and convex curvatures made from a bis-urea modified polycaprolactone material. Solvent cast chips containing a 50–500 µm diameter range of both concave and convex semicylindrical structures are successfully produced. Concave structures are completely covered by cells under all conditions. Yet cell layers present gaps on the summits of convex structures; the relative gap size enlarges as the diameter decreased. Increased proliferation time and cell seeding density allow for cells to overcome summit avoidance and nearly engulf convex structures. Interestingly, sample inversion also results in gap closure on convex structures during live imaging. Polarization of RPTECs is more prominent on concave compared to convex structures. These findings suggest that biomedical applications such as the bioartificial kidney should focus on concave seeding of cells to acquire more functional cell monolayers.