Synergistic chondrogenesis promotion and arthroscopic articular cartilage restoration via injectable dual-drug-loaded sulfated hyaluronic acid hydrogel for stem cell therapy

Bone marrow stem cells (BMSCs)-loaded injectable hydrogels are promising vehicles for the restoration of articular cartilage defect (ACD), while was limited with insufficient chondrogenic capacity and poor maintenance of chondrogenic phenotype. Herein, we reported a dual-drug delivering sulfated hyaluronic acid (SHA) hydrogel with injectable capacity to promote ACD repairment. Two precursor solutions were initial prepared: the HA-CHO-SO3 solution loaded with Kartogenin (KGN), β-cyclodextrin-CHO (β-CD-CHO) and BMSCs, and the HA-NHNH2-SO3 loaded with transforming growth factor β1 (TGF-β1) and BMSCs. The HA-CHO-SO3 could adsorb TGF-β1 through sulfonic acid group, and β-CD-CHO could preabsorb KGN through a hydrophobic cavity on β-CD. The aldehyde group on β-CD-CHO could react directly with the acylhydrazide to load KGN onto the HA-NHNH2-SO3 network. The mixture of two solutions resulted in the formation of a SHA@KGN/TGF-β1 hydrogel through reversible dynamic Schiff-based cross-linking between hydrazide and aldehyde groups. The SHA@KGN/TGF-β1 hydrogel had the benefits of injectability, rapid gelation, self-healing, and firm adhesion to the host tissue due to the reaction between the amine group on the host tissue and the aldehyde group on the SHA. Additionally, it could simultaneously load both TGF-β1 and KGN through electrostatic reaction and host-guest reaction, respectively, providing sustained release kinetics for both drugs. The dual-loaded drugs in the SHA@KGN/TGF-β1 hydrogel could synergistically enhance chondrogenic differentiation and suppress the hypertrophy of BMSCs, effectively promoting cartilage regeneration at both in vitro and in vivo circumstance. The one-step construction of this hydrogel system via mixing injection endowed facile arthroscopic ACD restoration and may significantly promote clinical application.