Effect of dual-pore 3D printed scaffolds on the osteogenic differentiation of MG-63 cells

Abstract

Along with aging of the population, and development of science, research on replacing organs and tissues has been actively conducted in the field of tissue engineering. Recently, manufacturing technologies for bone tissue engineering are growing with an understanding of the biology involved in bone regeneration. Among the various technologies, 3D printing is becoming popular due to its ability to directly print porous scaffolds with designed shape, controlled mechanical properties and interconnected porosity. Porous structure of scaffolds plays an important role in extracellular matrix (ECM) production, ingrowth of bone tissues, and loading active agents. In this study, a scaffold having dual porous structure was fabricated through 3D printing by fused deposition modeling (FDM) using foamable poly (lactic acid) (PLA) filament. To impart the foamability, PLA was extruded using twin extruder after mixing with epoxy chain extender and chemical foaming agent. Osteoblast-like MG-63 cells were cultured for 14 days on the prepared scaffolds coated with osteoconductive materials such as hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP), and HA/β-TCP (1:1) mixture, and cell adhesion, proliferation, and alkaline phosphatase (ALP) activity for bone differentiation were analyzed. 3D printed scaffolds having macro/micro-sized dual porous structure were successfully fabricated with one-step 3D printing process, and micropores present in the scaffolds were confirmed to be more effective in loading osteoconductive materials on the surface of scaffolds. Compared to neat PLA scaffolds fabricated without foaming process, dual-pore 3D printed scaffolds showed better results in cell adhesion, cell growth, protein synthesis, and ALP activity, particularly when β-TCP or HA/β-TCP was coated on the surface of scaffolds. The results suggest that our scaffolds are highly effective in osteogenic differentiation and are promising for bone tissue engineering applications