Harnessing Theraoenergetics for Cartilage Regeneration: Development of a Therapeutic and Bioenergetic Loaded Janus Nanofiber Reinforced Hydrogel Composite for Cartilage Regeneration

Advancements in tissue engineering and regenerative medicine have highlighted different strategies of engineering and designing hydrogels to replicate the intricate structure of cartilage extracellular matrix (ECM) for effective cartilage regeneration. However, despite efforts to meet the elevated structural and mechanical demands of cartilage repair, researchers often overlook the challenging environmental conditions at damaged cartilage sites such as inflammation, hypoxia, and the limited availability of nutrients and energy, which are critical for supporting tissue regeneration. The insufficient oxygen, nutrient availability, and oxidative stress in avascular cartilage limit the oxidative phosphorylation-mediated bioenergetics in cells needed for energy demands required for anabolic biosynthesis, cell division, and migration during tissue repair. Thus, there is a need to develop an advanced approach to engineer a unique hydrogel system that not only provides intricate structural properties but also integrates therapeutics (like anti-inflammatory, reactive oxygen species (ROS) scavenging) and bioenergetics (like oxygen, energy demand) into the hydrogel, which may offer a holistic and effective solution for repairing cartilage defects under a harsh microenvironment. In this study, we engineered an innovative approach to develop a new class of theraoenergetic hydrogel system by reinforcing a Janus nanofiber (JNF) carrying therapeutic (MgO) and bioenergetic (polyglutamic acid), PGA) components into a dual network photo-crosslinkable hydrogel. Reinforcement of JNF microfragments and the photo-crosslinking dual network of synthesized gelatin methacryloyl (GelMA) and carboxymethyl chitosan (CMCh) not only enhances the hydrogel's mechanical properties by 800% to withstand mechanical load but also ensures a controlled release of magnesium, oxygen, and PGA over 30 days. Co-delivery of magnesium and bioenergetic PGA with oxygen helped synergistically to reduce intracellular ROS and inflammatory markers IL-6 and TNF-α, providing a supportive environment for enhancing cell mitochondrial oxidative metabolism leading to active proliferation and chondrogenic differentiation of stem cells to deposit glycosaminoglycan (GAG)-rich extracellular matrix to regenerate cartilage. The developed theraoenergetic hydrogel system represents a promising solution for regenerating cartilage under a harsh microenvironment to treat osteoarthritis, a rising global health burden.