Natural-based injectable hydrogels for osteoarthritis treatment

Osteoarthritis (OA), the most common form of inflammatory arthritis in the world, is listed by the World Health Organization as one of the ten leading causes of disease burden in high-income countries. Unfortunately, there is no cure treatment for OA, and most treatments available focus on symptom management and slowing disease progression. Tissue engineering holds great promise in the repair of damaged cartilage and bone tissue. Regarding the applicability of hydrogels for tissue engineering, injectable hydrogels have proven large potential to be used in cartilage and bone tissue engineering as three-dimensional cell culture scaffolds, not only due to their high-water content, extracellular matrix similarity and suitable porosity for cell proliferation but also due to their minimally invasive application and capacity to match irregularly shaped defects. This chapter will provide an overview of distinct natural materials, bioactive molecules and cells frequently exploited in the production of injectable hydrogels, using either physical or chemical crosslinking gelation methods, which guarantee excellent injectable hydrogel design for cartilage and bone repair. Finally, we conclude with the future perspectives for injectable hydrogels in cartilage tissue engineering.