Abstract
Summary Statement
A three dimensional meniscal scaffold with controlled fibre diameter and orientation was fabricated by an improved E-Jetting system that mimic the internal structure of natural meniscus. In vitro cellular tests proved its feasibility in meniscal tissue engineering applications.
Introduction
Current surgical and repair methods for complex meniscal injuries still do not often give satisfactory long-term results. Thus, scaffold-based grafts are the subject of much research interest. However, one major hurdle is that current techniques are unable to replicate the precise 3D microstructure of meniscus, nor the variations in the fibrillar structure and tissue content from layer to layer. In this work, an improved electrohydrodynamic jet printing system (E-Jetting system) was developed to fabricate biomimetic meniscal scaffold for tissue regeneration.
Methods
Polycaprolactone (PCL) and ACS reagent grade acetic acid were purchased from Sigma-Aldrich. 70% w/v PCL solution was prepared by dissolving polymer in acetic acid. A customised hydrodynamic E-Jetting system was employed to fabricate the scaffold. Scaffold topography was observed by optical microscope (OM) and scanning electron microscope (SEM). Chondrocytes were used to evaluate the in vitro biological properties of scaffolds, including cell viability, sulfated glycosaminoglycan (sGAG) production, as well as gene expression of chondrogenic markers. Mechanical testing was also performed on the scaffolds with and without cell loading.
Results
Meniscal scaffolds of specific fiber orientation were fabricated in a single fabrication run at room temperature. These scaffolds were printed with circumferentially oriented PCL fibers interspersed with radial fibers, which mimic the internal structure of the natural meniscus. In vitro cell culture tests demonstrated that chondrocytes attached and spread well on the scaffolds, and produced significant extracellur matrix of cartilage (sGAG and collagen type II). Mechanical test was conducted on the meniscus scaffolds. Significantly enhanced tensile strength was seen on cell-laden scaffolds compared with that without cells.
Discussion/Conclusion
The three dimensional meniscal scaffold with controlled fibre diameter and orientation fabricated by the improved E-Jetting system was able to approach the internal structure of natural meniscus. Chondrocytes attached and spread well on the scaffolds, maintained their healthy phenotypes within the scaffold, and produced cartilage-like extracelluar matrix. Cell loading further enhanced the mechanical strength of scaffolds and replicated the anisotropic mechanical property of natural meniscus. It is proposed that the E-jetted meniscal scaffold has the potential for future applications in meniscal replacement therapeutic options.
