ABSTRACT
Three-dimensional bioprinting is a powerful technique for manufacturing improved engineered tissues. Three-dimensional bioprinted hydrogels have significantly advanced the medical field to repair cartilage tissue, allowing for such constructs to be loaded with different components, such as cells, nanoparticles, and/or drugs. Cartilage, as an avascular tissue, presents extreme difficulty in self-repair when it has been damaged. In this way, hydrogels with optimal chemical and physical properties have been researched to respond to external stimuli and release various bioactive agents to further promote a desired tissue response. For instance, methacryloyl gelatin (GelMA) is a type of modified hydrogel that allows for the encapsulation of cells, as well as oxygen-releasing nanoparticles that, in the presence of an aqueous medium and through controlled porosity and swelling, allow for internal and external environmental exchanges. This review explores the 3D bioprinting of hydrogels, with a particular focus on GelMA hydrogels, to repair cartilage tissue. Recent advances and future perspectives are described.
ABSTRACT
Cartilage is one of our body's tissues which are not repaired automatically by itself. Problems associated with cartilage are very common worldwide and are considered the leading cause of pain and disability. Smart biomaterial or "Four dimensional" (4D) biomaterials has started emerging as a suitable candidate, which are principally three dimensional (3D) materials that change their morphology or generate a response measured at space and time to physiologic stimuli. In this context, the release of oxygen through hydrogels in contact with water is considered as 4D biomaterials. The objective of this study is to develop strategies to release oxygen in a sustainable and prolonged manner through hydrogels systems to promote chondrocytes survival in oxygen-free environment. The 4D biomaterials are engineered from gelatin methacryloyl (GelMA) loaded with calcium peroxide (CPO), which have the ability to generate oxygen in a controlled and sustained manner for up to 6 days. The incorporation of CPO into the hydrogel system provided materials with enhanced mechanical and porosity properties. Furthermore, the hydrogels promoted chondrocyte survival and reduced cell death under oxygen-free conditions.
