Fabrication of polylactic acid (PLA)-based porous scaffold through the combination of traditional bio-fabrication and 3D printing technology for bone regeneration

Artificial bone grafts possess the advantages of good biodegradability, customizable dimensions, and sufficient mechanical properties, which can promote cell proliferation and differentiation in bone tissue regeneration. 3D printing is a delicate approach that endows the scaffolds with excellent controllability and repeatability when compared with conventional bio-fabrication methods. However, the limitation of printing resolution somehow makes it difficult to prepare bone defect substitution with high porosity and hierarchical construct. In this study, we utilized polylactic acid (PLA) as printing materials and developed a smart strategy to combine 3D printing technology with bio-fabrication methods. A porous planar scaffold was printed and then rolled up into a spiral structure with adjustable pore size and porosity. The topographic features and morphology of the artificial scaffolds were examined through stereomicroscope and SEM, respectively. The porous spiral scaffold presented good mechanical properties in a set of mechanical testing. Later, the human fetal osteoblasts (hFOB) were cultured on the porous spiral scaffold and its control groups for a total of 28 days. The MTS analysis, alkaline phosphatase (ALP) assay, and alizarin red S (ARS) staining were used to analyze the cell proliferation, osteogenic differentiation, and mineral deposition after a certain period of time. The results indicated that compared with the other two scaffolds, the porous spiral scaffold with larger surface area and better interconnections between internal porous networks could significantly improve the spatial cell compartment and promote cell growth and differentiation. The porous spiral scaffold may see versatile applications in large-volume bone defects regeneration.