Multifunctional load-bearing hybrid hydrogel with combined drug release and photothermal conversion functions

The inability of damaged load-bearing cartilage to regenerate and self-repair remains a long-standing challenge in clinical settings. In the past, the use of PVA hydrogels as cartilage replacements has been explored; however, both pristine and annealed PVA are not ideal for load-bearing cartilage applications, and new materials with improved properties are highly desirable. In this work, we developed a novel hybrid hydrogel system consisting of glycerol-modified PVA hydrogel reinforced by a 3D printed PCL-graphene composite scaffold. The composition of the hydrogel within the hybrid material was optimized to achieve high water retention and enhanced stiffness. The hybrid hydrogel formed by reinforcement with a 3D printed PCL-graphene scaffold with optimized architecture demonstrated desirable mechanical properties (stiffness, toughness and tribological properties) matching those of natural load-bearing cartilage. Our novel hydrogel system has also been designed to provide drug release and on-demand photothermal conversion functions and at the same time offers excellent biocompatibility with low cell adhesion. These promising properties may allow our unique hybrid hydrogel system to be used for potential applications, such as load-bearing cartilage repair/replacement, as well as targeting certain challenging clinical conditions, such as the treatment of severe arthritis.