ABSTRACT
Cartilage tissue has limited regenerative capacity when it is damaged due to common reasons like systemic disorders, degeneration, trauma, sports-related injuries, etc. Current treatments for cartilage repair are unsatisfactory and rarely restore the full functionality of native tissue. Therefore, a tissue engineering approach based on three-dimensional (3D) scaffolds is often used to produce functional cartilage tissue substitutes. Among 3D biomaterials, hydrogels have been extensively examined as scaffolding materials for cartilage tissue engineering because of their biocompatibility, controllable mechanical properties, flexibility, high water content, and ability to encapsulate various cells and bioactive agents. However, constructing hydrogel scaffolds in 3D structures with the stabilization of the desired shape is challenging due to the low viscosity of hydrogel precursors. 3D printing is the most convenient method to generate custom-made hydrogel scaffolds with varying sizes, shapes, and resolutions. These scaffolds should meet requirements similar to those of natural cartilage tissue in terms of appropriate architectural, physicochemical, and biological properties. Furthermore, the rheological properties must also be considered in order to use hydrogels as ink. This chapter summarizes recent approaches to engineering hydrogels for 3D printing cartilage repair with an eye toward eventual clinical translation.
