Tuning the viscoelastic response of hydrogel scaffolds with covalent and dynamic bonds

The processes of growth, proliferation and differentiation of stem cells encapsulated in 3D hydrogel microenvironments are strongly affected by the viscoelastic properties of the platforms. As the viscoelastic response of a hydrogel is determined by the rates of thermally induced dissociation of reversible cross-links, its modulation by introduction of several types of supramolecular and/or dynamic covalent bonds with different characteristic lifetimes has recently become a hot topic. To reduce the number of experiments needed for design of hydrogel microenvironments with required mechanical properties, a model is developed for the viscoelastic and viscoplastic responses of hydrogels with multiple networks bridged by covalent and physical bonds. An advantage of the model is that it (i) involves a small number of material parameters, (ii) describes observations in rheological and mechanical tests in a unified manner, and (iii) predicts conventional measures of viscoelasticity used in the analysis of viability of cells.

Automated summary

The viscoelastic properties of hydrogel microenvironments have a strong impact on the growth, proliferation, and differentiation processes of stem cells. Recent research has focused on modulating the viscoelastic response of hydrogels by introducing supramolecular and/or dynamic covalent bonds. To reduce the number of experiments required for designing hydrogel microenvironments with specific mechanical properties, a model has been developed that describes the viscoelastic and viscoplastic responses of hydrogels with multiple networks bridged by covalent and physical bonds. This model offers advantages in terms of material parameters, unified description of test results, and prediction of conventional measures of viscoelasticity used in cell viability analysis.