An injectable, click-crosslinked, cytomodulin-modified hyaluronic acid hydrogel for cartilage tissue engineering

摘要

This is the first report, to our knowledge, of the preparation of an injectable in situforming click-crosslinked hyaluronic acid (Cx-HA) hydrogel (Cx-HA-CM) containing chemical immobilized cytomodulin-2 (CM), a chondrogenic differentiation factor, and on the utility of human periodontal ligament stem cells (hPLSCs) as a cell source for cartilage tissue engineering.hPLSCs served here as a stem cell source tolerant to ex vivo manipulation.CM induced in vitro chondrogenic differentiation of hPLSCs comparable to induction with traditional TGF-.Cx-HA was prepared via a click-reaction between tetrazine-modified HA and transcyclooctene-modified HA.Cx-HA displayed significantly more features of a stiff hydrogel than HA.Cx-HA had a three-dimensional porous interconnected structure, absorbed a large volume of biological medium, and showed excellent biocompatibility.In contrast to HA, the Cx-HA hydrogel persisted in vitro and in vivo for an extended period, as evidenced by in vivo near-infrared fluorescence imaging.CM covalently linked to Cx-HA (Cx-HA-CM) remained inside Cx-HA for a prolonged period compared with CM physically loaded onto Cx-HA [Cx-HA (+CM)].Cx-HA-CM also caused better chondrogenic differentiation of hPLSCs, as evidenced by Alcian blue and Safranin O staining, and greater increases in the expression of type II collagen, glycosaminoglycan content and SOX9, aggrecan, and type 21 collagen mRNA levels.Thus, compared to Cx-HA (+CM), the hPLSC-loaded Cx-HA-CM hydrogel induced greater chondrogenic differentiation of hPLSCs via CM that was retained in the hydrogel for a much longer period of time.Injectable polymers that spontaneously form three-dimensional porous scaffolds may make it easier to repair cartilage tissue in arthritis sufferers.Recent findings have shown that periodontal stem cells harvested from tissue surrounding human teeth can differentiate into cartilage cells when seeded onto scaffolds containing bioactive peptides.Moon Suk Kim from Ajou University in Suwon, South Korea, and colleagues have now improved this approach by chemically attaching peptides that mimic natural growth factors to water-filled polymers called hydrogels.Cell culture experiments demonstrated that this new material improved resistance against breakdown compared with hydrogels containing physically absorbed bioactive peptides.By injecting live mice with injectable polymers, the team induced hydrogels via click-crosslink into a subcutaneous scaffold loaded with periodontal stem cells.Hydrogels revealed the formation of cartilagelike tissues over four weeks without causing inflammation.In this work, we confirmed that an in situforming click-crosslinked hyaluronic acid (Cx-HA) hydrogel with chemical immobilization of cytomodulin-2 (CM) (Cx-HA-CM) and human periodontal ligament stem cells (hPLSCs) have a good potential for cartilage tissue engineering.The CM that is retained inside the Cx-HA hydrogel for a long time synergistically induces chondrogenic differentiation of hPLSCs.Therefore, such an injectable formulation of the Cx-HA-CMbased hydrogel proposed in this work provides an opportunity to satisfy the unmet need for (pre)clinical repair of damaged articular cartilage.