(265f) Covalently Adaptable Networks As Biophysical-ECM Mimics for Cell Culture

Covalently crosslinked synthetic hydrogels are especially suitable as tissue engineering scaffolds due to their well-defined and easily tunable biochemical and biophysical properties. In order to enable complex cell functions like ECM deposition, motility, and spreading, a mechanism for crosslink degradation must be engineered into the material; however, the presence of a degradation trigger can complicate the cellular biophysical microenvironment. Furthermore, covalently crosslinked polymers typically produce an elastic material, while native tissues are complex viscoelastic structures. Here, we present a step-growth poly(ethylene glycol) (PEG) hydrogel crosslinked by reversible hydrazone bonds. The macromer components are readily synthesized from commercially available precursors, and the resulting gels form rapidly under physiological conditions and provide a non-toxic matrix that is suitable for cell culture. This material is capable of mimicking aspects of the viscoelastic properties of native tissues, and the dynamic stress relaxing crosslinks permit complex cellular functions to occur while retaining the benefits of traditional covalently crosslinked hydrogels. Taken together, these attributes make hydrazone crosslinked hydrogels a unique tool for designing viscoelastic scaffolds and studying cellular responses to scaffold elasticity.