Developing Bioactive Hydrogels Containing Cell-derived Extracellular Matrix: Implications in Drug and Cell-free Bone and Cartilage Repair

The prevalence of osteoarthritis has been increasing in aging populations, which has necessitated the use of advanced biomedical treatments. These involve grafts or delivering drug molecules entrapped in scaffolds. However, such treatments often show suboptimal therapeutic effects due to poor half-life and off-target effects of drug molecules. This study aims to overcome these limitations by 3D printing gelatin-based hydrogel scaffolds containing cell-derived extracellular matrix (ECM) as the bioactive therapeutic cargo. Here, pre-osteoblastic and pre-chondrogenic murine cells were differentiated in vitro, decellularized, and incorporated into methacrylated gelatin (GelMA) solutions to form osteogenic (GelO) and chondrogenic (GelC) hydrogels, respectively. The integration of the bioactive decellularized extracellular matrix (dECM) allows GelO and GelC to induce differentiation in human adipose-derived stem cells (hADSCs) toward osteogenic and chondrogenic lineages. GelO and GelC can be covalently adhered using carbodiimide coupling reaction, forming bioactive osteochondral plug. Moreover, this osteochondral plug can also induce differentiation of hADSCs. To conclude, this ECM-based bioactive hydrogel offers a promising new drug-free and cell-free treatment strategy for bone and cartilage repair, and future osteoarthritis management.