Effect on three-dimensional collective cell organization of minimal curvature surfaces

Collective cell organization can be influenced by surface curvature, as studied in cylindrical, spherical, and sinusoidal surfaces; however, hyperbolic geometries have been overlooked due to their biofabrication complexity, despite their presence in biological structures, and their potential role in minimizing cell bending energy. Therefore, understanding cell behavior in complex-hyperbolic geometries is important to design in vitro biomimetic platforms and scaffolds. This work studies the role of curvature on collective cell spatiotemporal growth and adhesion, using the gyroid, a minimal periodic hyperbolic surface. The gyroid biofabrication has been limited by its interconnected curved structure, which is solved here by using its fundamental unit of symmetry, parametrized in terms of mean and Gaussian curvatures, achieving its biofabrication with>90% of resolution, allowing the exploration of its effect in guiding cell behavior, isolating the curvature variable from substrate stiffness and extracellular ligands. Three cell lines were studied: two epithelial-like (HEPG2 and HEK293), and one fibroblastic (NIH3T3), using superficial cell seeding and cell hydrogel encapsulation. It was observed by confocal microscopy that the gyroid was able to orient and guide the cells cytoskeleton in the direction to minimize their energy, showing less nuclei compression and eliciting more confluency than in semi-spheres and flat surfaces.