Using Competitor Molecules to Reversibly Modulate the Mechanical Properties of Viscoelastic Hydrogels

We report a new strategy that allows reversible tuning of the stiffness and stress-relaxation of viscoelastic hydrogels cross-linked via hydrazone bonds by incorporating a small-molecule competitor. The competitor molecule competes for the formation of reversible hydrazone bonds and temporarily reduces the cross-linking density in the hydrogel, thus softening the hydrogel and accelerating its stress-relaxation. By rapidly diffusing the competitor in and out of the hydrogel, the mechanical properties of hydrogels can be reversibly altered over many cycles. We further examined the biocompatibility of the competitor and explored its application in cell delivery via injection by temporarily adjusting the hydrogel mechanical properties to improve cell viability during the injection.

Automated summary

In this study, we introduce a new strategy to reversibly tune the stiffness and stress-relaxation of hydrazone-crosslinked hydrogels by incorporating a small-molecule competitor. By adjusting the cross-linking density, the mechanical properties of hydrogels can be altered, which has potential applications in cell delivery to improve cell viability during injection.