UC San Diego

Micropatterning technologies have demonstrated that cell shape is a major regulator of cell behavior and differentiation status, but are typically limited to flat culture systems. The geometry of three-dimensional (3D) culture environments has also been shown to significantly influence cell function, including driving cancer progression and aggression. 3D tissues typically present a topographically complex fibrous adhesive environment, which is technically challenging to replicate and modulate in a controlled manner to provide a more physiologically relevant system for studying cell behavior. In this work, we develop a technique for systematically modulating 3D collagen fiber topography and architecture using inert molecular crowding agent, polyethylene glycol (PEG). Breast cancer cells, MDA-MB-231, were then embedded into the PEG-crowded collagen hydrogels and quantitatively characterized in terms of their morphology and migration. Herein, we demonstrate that the features of collagen gels such as fiber length, fiber width, pore size, and topographical heterogeneity, can be controlled independently of bulk density and stiffness through molecular crowding during polymerization. Then, we show that these alterations result in distinct 3D matrices that embedded cells perceive and interact with. Architectural differences are found to directly influence cell morphology, migration behavior, and phenotypic heterogeneity.