3D printing-Based strategies for functional cartilage regeneration.

The regeneration of cartilage has made great progress in the past few decades， Previous techniques for constructing tissue-engineered cartilage scaffolds mainly include particulate-leaching, gas-foaming, freeze-drying and phase-separation techniques. Cartilage is heterogeneous, and it is difficult for traditional scaffolds to simulate such anisotropy. Therefore, the functional regeneration of cartilage is challenging. With advancements in additive manufacturing, it has become possible to prepare functional bionic scaffolds for structures and components by the codeposition of biological materials, cells and active biomolecules, thereby achieving functional cartilage regeneration. This paper reviews the applications of 3D printing techniques in the regeneration of cartilage at different anatomical locations, including articular cartilage, meniscus, intervertebral disc and auricle. In addition, methods for preparing biomimetic constructs with regional structural gradients and regional componential gradients are discussed, with multinozzle 3D bioprinting technology as a future research direction for the functional regeneration and repair of cartilage.