Enhancing the maturity of in vitro engineered cartilage from Wharton's jelly-derived photo-crosslinked hydrogel using dynamic bioreactors and its in vivo outcomes in animal models.

Abstract

The immature state of in vitro engineered cartilage (IVEC) hinders its clinical translation, highlighting the need for optimized scaffold platforms and cultivation models. Our previous work demonstrated that Wharton's jelly (WJ) contains an extracellular matrix (ECM) whose composition closely resembles that of native cartilage and includes several bioactive factors that promote chondrogenic induction. Furthermore, earlier studies have shown that photo-crosslinkable hydrogels are ideal carrier scaffolds for cartilage tissue engineering and that bioreactors improve nutrient and waste exchange between scaffolds and the culture medium. Based on these findings, we employed a dynamic bioreactor in combination with a WJ-derived photo-crosslinkable hydrogel to enhance IVEC maturity. Our results indicate that the decellularized WJ matrix (DWJM) effectively retains its native chondrogenic ECM components and bioactive factors. The photo-crosslinkable ADWJM hydrogel-produced by modifying DWJM with methacrylate anhydride-demonstrated excellent gelation capacity as well as tunable rheological properties, swelling ratios and degradation rates across different DWJM concentrations. In addition, the ADWJM hydrogel exhibited outstanding biocompatibility by providing a favorable 3D microenvironment for chondrocyte survival and proliferation. Most importantly, the dynamic bioreactor markedly promoted IVEC maturation. Constructs cultured under dynamic conditions displayed increased thickness, wet weight and volume; enhanced mechanical strength; more typical lacunae structures; and uniform deposition of cartilage-specific ECM compared to constructs maintained in static conditions or within a static bioreactor. Moreover, in vivo subcutaneous implantation of IVEC in goats further validated these findings, as the implanted constructs exhibited cartilage components and mechanical properties closely resembling those of natural cartilage. These results offer a promising approach for enhancing IVEC maturity and support its future clinical translation.