Summary
Development of 3D-Printed Meniscus Scaffold with Composite Material for Zone-Specific Properties to Mimic Native Meniscus
Abstract
Introduction
The meniscus is vital for knee function, playing a key role in shock absorption and load distribution. Injuries from sports, aging, or trauma can lead to complications like osteoarthritis if untreated. Current treatments, such as meniscectomy and artificial replacements, often struggle with durability and fit. In this study, we developed a 3D-printed artificial meniscus that mimics the native tissue's structure and mechanical properties. Using a dual-nozzle 3D printing technique, we combined polymer composite (PCL/nanohydroxyapatite, HA) and hydrogel to enhance meniscal replacement performance. We hypothesized that incorporating HA into PCL would improve mechanical properties. To replicate the zone-specific composition of the meniscus, we used specialized hydrogels: PVA-g-GMA/SF-g-GMA for the chondrogenic inner zone and GelMA for the fibrogenic outer zone. We anticipate that this 3D-printed HA-reinforced PCL/hydrogel will effectively mimic human meniscus tissue, providing a promising solution for improved meniscus repair.
Methods
We produced samples with varying HA contents (5%, 10%, 15% w/w of PCL) to study HA's effect on mechanical properties. Xanthan gum (XG) was added to the hydrogel to enhance viscosity and optimize printability. We determined the optimal PCL/HA and hydrogel formulations, and a 3D bioprinter with dual-nozzle printing was used to fabricate an artificial meniscus mimicking native meniscus zones. The outer zone was created with PCL/HA and GelMA hydrogel, while the inner zone was formed with PCL/HA and PVA-g-GMA/SF-g-GMA hydrogel. We analyzed the artificial meniscus's optical appearance, morphology, porosity, surface wettability, and mechanical properties.
Results
Adding HA significantly improved the mechanical properties of the 3D-printed PCL composite. The PCL/10HA formulation showed the highest potential for artificial meniscus applications, with superior compressive and tensile properties closely resembling human meniscus tissue. For hydrogel printability, GelMA with 4% XG was selected for the outer zone, and PVA-g-GMA/SF-g-GMA with 3% XG was used for the inner zone. The 3D-printed PCL/HA/hydrogel meniscus showed promising properties. The outer zone exhibited compressive strength of 20.67 ± 3.39 MPa, tensile strength of 7.78 ± 0.32 MPa, and tensile modulus of 80.35 ± 10.77 MPa, while the inner zone had compressive strength of 21.26 ± 3.58 MPa, tensile strength of 8.05 ± 0.76 MPa, and tensile modulus of 89.37 ± 9.01 MPa. Both zones had similar porosity (around 34%) and surface wettability, indicating the artificial meniscus effectively replicates human meniscus tissue.
Discussion
This study demonstrated that the 3D-printed HA-reinforced PCL/hydrogel composite effectively mimics human meniscus tissue's physical and mechanical properties. The dual-nozzle 3D printing method successfully created a zone-specific structure, confirming our hypothesis that HA enhances PCL's mechanical properties. Future research will focus on cell viability, gene expression, and immune responses, essential for validating the meniscus scaffold's efficacy and advancing toward animal model testing and potential clinical use.