Shear-Thinning Supramolecular Hydrogels with Secondary Autonomous Covalent Crosslinking to Modulate Viscoelastic Properties In Vivo

Clinical percutaneous delivery of synthetically engineered hydrogels remains limited due to challenges posed by crosslinking kineticstoo fast leads to delivery failure, too slow limits material retention. To overcome this challenge, supramolecular assembly is exploited to localize hydrogels at the injection site and introduce subsequent covalent crosslinking to control final material properties. Supramolecular gels are designed through the separate pendant modifications of hyaluronic acid (HA) by the guest-host pair cyclodextrin and adamantane, enabling shear-thinning injection and high target site retention (>98%). Secondary covalent crosslinking occurs via addition of thiols and Michael-acceptors (i.e., methacrylates, acrylates, vinyl sulfones) on HA and increases hydrogel moduli (E = 25.0 +/- 4.5 kPa) and stability (>3.5 fold in vivo at 28 d). Application of the dual-crosslinking hydrogel to a myocardial infarct model shows improved outcomes relative to untreated and supramolecular hydrogel alone controls, demonstrating its potential in a range of applications where the precise delivery of hydrogels with tunable properties is desired.