3D Bioprinted Implants for Cartilage Repair in Intervertebral Discs and Knee Menisci

Abstract

Cartilage defects pose a significant clinical challenge as they can lead to joint pain, swelling and stiffness, which reduces mobility and function thereby significantly affecting the quality of life of patients. More than 250,000 cartilage repair surgeries are performed in the United States every year. The current gold standard is the treatment of focal cartilage defects and bone damage with nonflexible metal or plastic prosthetics. However, these prosthetics are often made from hard and stiff materials that limits mobility and flexibility, and results in leaching of metal particles into the body, degeneration of adjacent soft bone tissues and possible failure of the implant with time. As a result, the patients may require revision surgeries to replace the worn implants or adjacent vertebrae. More recently, autograft – and allograft-based repair strategies have been studied, however these too are limited by donor site morbidity and the limited availability of tissues for surgery. There has been increasing interest in the past two decades in the area of cartilage tissue engineering where methods like 3D bioprinting may be implemented to generate functional constructs using a combination of cells, growth factors (GF) and biocompatible materials. 3D bioprinting allows for the modulation of mechanical properties of the developed constructs to maintain the required flexibility following implantation while also providing the stiffness needed to support body weight. In this review, we will provide a comprehensive overview of current advances in 3D bioprinting for cartilage tissue engineering for knee menisci and intervertebral disc repair. We will also discuss promising medical-grade materials and techniques that can be used for printing, and the future outlook of this emerging field.

Reviving Intervertebral Discs: Treating Degeneration Using Advanced Delivery Systems

“…As a personalized and flexible technology, 3D bioprinting has a broad application prospect in repairing IVDs. 125 Depending on the device, printing parameters, and printing time, 3D printing technology can not only print biological materials but also accurately place growth factors or cells. Sun et al 101 developed polydopamine nanospheres loaded with TGF-β3/connective tissue growth factor (CTGF) and mixed them with bone marrow MSCs and hydrogel to design and fabricate IVD scaffolds using a novel 3D printing technique.…”

Advances in 3D Bioprinting of Biomimetic and Engineered Meniscal Grafts

“…Extensive studies have shown that 3D bioprinting, [2] as a promising method, enables the design of spatially complex tissue structures in vitro and their potential implantation in vivo, providing an alternative approach for treating meniscal injuries. [3][4][5] Both meniscectomy and meniscus repair, as well as the utilization of meniscus allograft, have limitations in fully restoring the biomechanical properties and stability of the knee joint. Overcoming the challenge of reconstructing the structural inhomogeneity and anisotropy of the meniscus is a significant hurdle in clinical practice.…”

“…Extensive studies have shown that 3D bioprinting, [ 2 ] as a promising method, enables the design of spatially complex tissue structures in vitro and their potential implantation in vivo, providing an alternative approach for treating meniscal injuries. [ 3–5 ]…”

Development, Pathogenesis, and Regeneration of the Intervertebral Disc: Current and Future Insights Spanning Traditional to Omics Methods

“…Natural materials such as chitin, gelatin, and alginate have also been used to produce hydrogels like chitosan and gelatin methacryloyl (GelMA) that act as scaffolds and promote ECM production ( Guo et al, 2014 ; Li et al, 2017 ; Yang et al, 2020 ). Hydrogels and 3D printed implants to replace the damaged NP have shown potential to restore disc height and reduce pain ( Schmocker et al, 2016 ; Perera et al, 2021 ).…”