Viscoelastic and phototunable GelMA-alginate hydrogels for 3D cell culture

In this study, we developed a biocompatible 3D viscoelastic interpenetrating network (IPN) hydrogel that can be stiffened (increasing in elastic modulus from 1 to 18 kPa) over time. Our approach utilizes a dual-crosslinking strategy. Ionically crosslinked alginate permits stress relaxation of the gel while radical-mediated photocrosslinking of gelatin methacrylate (GelMA) enables dynamic stiffening. We found this technique to be cytocompatible with no significant loss of viability of mouse bone marrow stromal cells (MSC). This hydrogel platform is broadly applicable in 3D cell culture systems to better recapitulate the dynamic and time-dependent mechanics of the in vivo extracellular matrix (ECM).