Nanofiber Composite Microchannel-Containing Injectable Hydrogels for Cartilage Tissue Regeneration.

Articular cartilage tissue is incapable of self-repair and therapies for cartilage defects are still lacking. Injectable hydrogels have drawn much attention in the field of cartilage regeneration. Herein, we proposed the novel design of nanofiber composite microchannel-containing hydrogels inspired by the tunnel-piled structure of subway tu nnels. Based on the al dehydized polyethylene glycol/carboxymethyl chitosan (APA/CMCS) hydrogels, thermo-sensitive gelatin microrods (GMs) were used as a pore-forming agent, and coaxial electrospinning polylactic acid/gelatin fibers (PGFs) loaded with kartogenin (KGN) were used as a reinforcing agent and a drug delivery system to construct the nanofiber composite microchannel-containing injectable hydrogels (APA/CMCS/KGN@PGFs/GMs hydrogels). The in situ formation, micromorphology and porosity, swelling and degradation, mechanical properties, self-healing behavior, as well as drug release of the nanofiber composite microchannel-containing hydrogels were investigated. The hydrogel exhibited good self-healing ability, and the introduction of PGFs nanofibers could significantly improve the mechanical properties. The drug delivery system could realize sustained release of KGN to match the process of cartilage repair. The microchannel structure effectively promotes bone marrow mesenchymal stem cells (BMSCs) proliferation and ingrowth within the hydrogels. In vitro and animal experiments indicated that the APA/CMCs/KGN@PGF/GM hydrogels could enhance the chondrogenesis of BMSCs and promote neocartilage formation in the rabbit cartilage defect model. This article is protected by copyright. All rights reserved.