Unveiling the potential use of bioprinting materials in directing stem cell fate for cartilage regeneration: Focusing on induced pluripotent stem cells and enhanced lubrication (Review)

Cartilage is a strong, yet flexible, type of connective tissue found in various parts of the body.Cartilage that covers the ends of bones in joints, referred to as articular cartilage, is frequently damaged during injuries and osteoarthritis (OA).Lack of blood vessels and nerves in the cartilage limits its self-renewal capacity, rendering cartilage regeneration a critical challenge.Three-dimensional (3D) bioprinting provides a promising approach for cartilage regeneration by depositing bioink layer by layer to create a 3D structure of more complex tissues such as cartilage, with clinically relevant sizes and mimicking the native shape and natural microenvironment.The present review discusses the potential of bioprinting materials to direct the fate of induced pluripotent stem cells (iPSCs) towards chondrocytes, while simultaneously enhancing lubrication.This will be achieved by incorporating iPSCs, natural polymers, synthetic polymers and lubricants such as lubricin, growth factors and signaling molecules that are involved in chondrogenesis.By optimizing bioink formulation and other parameters in bioprinters, the production of tissues in a precisely controlled manner is ensured, and limitations in current treatments for degenerative diseases such as OA can be avoided.Researchers have developed various complex and functional tissues and organs using bioprinting with successful animal trials, and are in the process of developing patient-specific iPSCs to generate personalized cartilage grafts having high and prolonged regenerative ability with further enhanced lubrication.The present review aimed to provide hope for patients suffering from cartilage degeneration by demonstrating the potential of 3D bioprinting for effective cartilage regeneration.Contents 1. Cartilage: A closer look, cartilage degradation and the challenge of regeneration 2. Stem cells and induced pluripotent stem cells 3. Chondrogenesis 4. Proliferation and pre-hypertrophic differentiation 5. Hypertrophic differentiation and endochondral ossification 6. MSC therapy for cartilage regeneration 7. Use of iPSCs for cartilage regeneration 8. Signaling pathways for chondrocyte differentiation 9. Influence of 2D and 3D cell culture systems on chondrogenesis 10. 3D bioprinting 11.Bioink 12. Lubrication 13.Comparison of 3D bioprinting with current treatments for OA and stem cell therapy 14.Future directions 15.Conclusion