Biomimetic 3D printed scaffolds for meniscus tissue engineering

The menisci distribute loads to protect the articular cartilage of the knee joint from excessive stress. Injuries to their avascular inner regions do not heal, disrupt function, and increase the risk for knee osteoarthritis. Meniscus tissue engineering aims to restore normal meniscus function by use of regenerated tissue on bioengineered scaffolds. The primary purpose of this study was to design and 3D print polycaprolactone scaffolds that recapitulate the shape and structural components of the meniscus extracellular matrix to provide a template and structural support for complete cell-based meniscus regeneration. A secondary aim was to characterize 3D printed polycaprolactone scaffold fibre architectures with varied fibre spacings, offsets between layers, and circumferential orientations in terms of their equilibrium compressive modulus. Meniscus scaffolds were produced layer-by-layer with a biomimetic fibre architecture inspired by the circumferentially- and radially- oriented collagen fibre bundles found in the native tissue. Suture tabs were incorporated to facilitate fixation at the meniscal horns and the coronary attachments. These scaffolds were designed to have 100% pore interconnectivity and 61% porosity. The equilibrium compressive modulus at 10% strain of the meniscus scaffold architecture was 18.8 ± 3.1 MPa (mean ± standard deviation, n = 3) and ultimate load in a suture pull-out test on the anterior horn suture tab was 32 N. The scaffolds produced in this study demonstrate a promising strategy for meniscus tissue engineering as they provide a complete biomimetic template for regeneration of functional components of the meniscus extracellular matrix.