The Intersecting Physical Mechanisms That Regulate Cell Viability in 3D Synthetic Hydrogels

Hydrogels restrict protein transport to different extents, with nanoporous synthetic polymer networks providing far less protein permeability compared to microporous biopolymer networks. To evaluate whether reduced permeability was a driving factor in reduced cell viability in synthetic hydrogels, we compared poly(ethylene glycol) vinyl sulfone (PEG-VS) hydrogels with Matrigel to quantify the influences of modulus, transport, and confinement on encapsulated cells. We observed extensive reductions in cell viability when encapsulated in PEG-VS gels compared to Matrigel. In transwell experiments that decouple hydrogel-restricted serum from cell-gel adhesion, serum restriction reduced cell viability, matching the cell viability observed in 3D cultures. Our unique combination of 2D and 3D hydrogel-based cell cultures provides a framework for investigating the intersecting effects of the cell microenvironment's properties on cell viability. This work demonstrates that biomaterial-restricted protein transport is a critical design consideration when using synthetic 3D cell culture hydrogels.