Enhanced tendon healing by a tough hydrogel with an adhesive side and high drug-loading capacity

A hydrogel serving as a high-capacity drug depot and combining a dissipative tough matrix on one side and a tendon-adhesive surface on the other side boosts tissue healing in rat models of tendon rupture. Hydrogels that provide mechanical support and sustainably release therapeutics have been used to treat tendon injuries. However, most hydrogels are insufficiently tough, release drugs in bursts, and require cell infiltration or suturing to integrate with surrounding tissue. Here we report that a hydrogel serving as a high-capacity drug depot and combining a dissipative tough matrix on one side and a chitosan adhesive surface on the other side supports tendon gliding and strong adhesion (larger than 1,000 J m(-2)) to tendon on opposite surfaces of the hydrogel, as we show with porcine and human tendon preparations during cyclic-friction loadings. The hydrogel is biocompatible, strongly adheres to patellar, supraspinatus and Achilles tendons of live rats, boosted healing and reduced scar formation in a rat model of Achilles-tendon rupture, and sustainably released the corticosteroid triamcinolone acetonide in a rat model of patellar tendon injury, reducing inflammation, modulating chemokine secretion, recruiting tendon stem and progenitor cells, and promoting macrophage polarization to the M2 phenotype. Hydrogels with 'Janus' surfaces and sustained-drug-release functionality could be designed for a range of biomedical applications.

Automated summary

A hydrogel with high-capacity drug storage function has been found to promote tissue healing in tendon injuries. This hydrogel has a tough structure on one side and an adhesive surface on the other, allowing it to support tendon gliding and strong adhesion. Through experiments, it has been shown that this hydrogel enhances healing and reduces scar formation in rat models of tendon rupture, and can sustainably release drugs. It has potential for biomedical applications.