Advances of injectable hydrogel-based scaffolds for cartilage regeneration

Abstract

Articular cartilage is an important load-bearing tissue distributed on the surface of diarthrodial joints. Due to its avascular, aneural and non-lymphatic features, cartilage has limited self-regenerative properties. To date, the utilization of biomaterials to aid in cartilage regeneration, especially through the use of injectable scaffolds, has attracted considerable attention. Various materials, therapeutics and fabrication approaches have emerged with a focus on manipulating the cartilage microenvironment to induce the formation of cartilaginous structures that have similar properties to the native tissues. In particular, the design and fabrication of injectable hydrogel-based scaffolds have advanced in recent years with the aim of enhancing its therapeutic efficacy and improving its ease of administration. This review summarizes recent progress in these efforts, including the structural improvement of scaffolds, network cross-linking techniques and strategies for controlled release, which present new opportunities for the development of injectable scaffolds for cartilage regeneration.

Keywords: cartilage regeneration; drug delivery; injectable hydrogel; tissue engineering.

Figure 1.

The schematic of the applications of injectable scaffolds for cartilage regeneration

Figure 2.

(A) The schematic of the anatomy, cell morphology and zonal features of articular cartilage, and its progression to different types of osteoarthritis. (B) The schematic of different structure scaffold networks utilized in the cartilage regeneration engineering

Figure 3.

The implantation of the cell-laden trilayer scaffold resulted in the formation of osteochondral tissue with a lubricin-rich cartilage surface. This figure was adapted with permission from Kang et al. [47]

Figure 4.

(A) Schematic of KGN-loaded PLGA NPs, molecule structures of KGN and acrylated HA (m-HA). (B) Schematic of the surgical procedure for cartilage defect repair. (C) Schematic of the hyaline cartilage chondrogenesis with the photo-cross-linked HA scaffold encapsulated with KGN-loaded NPs. This figure was adapted with permission from Shi et al. [161]