The Design and Characterization of a Strong Bio-Ink for Meniscus Regeneration

The meniscus is vital to the mechanical function of the knee, while it is frequently harmed because it bears a heavy load. A strong bio-ink for meniscus regeneration was prepared for the future meniscal tissue engineering. The prepared bio-ink consists of poly (vinyl alcohol) and decellularized extracellular matrix (PVA/dECM). The mechanical properties and the rheological features were explored to evaluate the effects of freezing/thawing cycles and alkaline treatment process. The printability was verified using a three-dimensional printer. The endothelial cells were employed to assess the biocompatibility. Finally, a 12-week rabbit meniscus defect model was established to evaluate the meniscus regeneration capability. We found that the bio-ink by soaking in alkaline for 40 min and 20 freezing/thawing cycles demonstrated excellent mechanical properties. The Young's modulus reached 0.49 MPa and the stress limitation was 2.9 MPa. The results also showed good printability and biocompatibility of the proposed bio-ink in vitro. The PVA/dECM hydrogel healed the meniscus defect after 12 weeks of implantation. The articular cartilage and subchondral bone exhibited normal microstructure and composition. These results suggested that the PVA/dECM hydrogel could be a promising solution to repair meniscal lesions with preventive effects against degenerative meniscal tears and post-traumatic arthritis.