Development of 3D-Printed Scaffolds with Mathematically Defined Curvature for Osteochondral Defect Repair Applications ^†

Scaffolds are one major component in osteochondral tissue engineering (OCTE) applications, acting as a structural support for cell proliferation and differentiation. However, the majority of described scaffolds present planar surfaces, compromising the reproduction of the natural curvature of the tissue (e.g., bone). Mimicking native tissue should be crucial, particularly in OCTE so that mechanical loads could be evenly distributed over the engineered constructs. In this work, a new strategy for the design of scaffolds is presented, using the radius of a sphere to characterize their curvature. Following a parametric design strategy, it becomes a versatile and efficient process to create scaffolds with diverse curvatures. The manufacture of the scaffolds was accomplished by fused filament fabrication (FFF) technique using the biocompatible, biodegradable and FDA-approved poly (lactic acid) (PLA) material. Considering the necessity for each layer to be printed over the bed or previously deposited material, a maximum curvature radius, to be produced by FFF, of 17.0638 mm was calculated for scaffolds with side dimensions of 20.1 mm × 20.1 mm. Curved scaffolds were manufactured with a radius of 17.0638 mm and 20 mm and structural integrity evaluated by micro-CT imaging, confirming the maximum curvature printability limitations. Additionally, finite element analysis (FEA) was used to assess the mechanical behavior of scaffolds to compressive loads. Considering these results, FFF curved scaffold manufacturing holds promising prospects to address the fabrication of scaffolds mimicking the natural curvature of osteochondral tissues.