A novel sucrose porogen-based solid freeform fabrication system for bone scaffold manufacturing

Purpose - Musculoskeletal conditions are a major health concern in the USA because of a large aging population and increased occurrence of sportrelated injuries. Bone tissue engineering may offer a less painful alternative to traditional bone grafts with lower risk of infection. The purpose of this paper is to present a novel porogen-based fabrication system for tissue engineering scaffolds using sucrose (C12H22O11) as the porogen building material. Design/methodology/approach - A new solid freeform fabrication system has been developed and tested, which uses pressurized extrusion to print highly biocompatible and water soluble sucrose bone scaffold porogens (or negtives). Polycaprolactone (PCL) scaffolds are manufactured by injecting molten polymer into the porogens, and the porogens are subsequently dissolved with water. The resultant scaffolds demonstrate the defined porous structure designed into the sucrose porogen manufacturing computer-aided design model. Findings - To optimize the porogen manufacturing process, the viscosity of sucrose mixtures is measured. Design of experiments is used to plan and analyze the relationships between the porogen characteristics and the process parameters. Reservoir pressure and print head speed are identified as the dominant factors affecting sucrose flow rate and porogen strut diameter, respectively. The biocompatibility of the new system is assessed by in vitro cell culture testing. Endothelial hybridoma cells (EAhy 926) and osteoblasts (7F2) seeded on the fabricated PCL scaffolds adhered to the scaffold and proliferated over four to six days. Epifluorescence and scanning electron microscopy images reveal cell spreading and multiple layers of cells on the scaffold surface. The results demonstrated the potential of the structured sucrose porogen-based fabrication method in manufacturing bone tissue scaffolds. Originality/value - This paper describes the first time use of biomaterials-sucrose to make scaffold porogens and how an injection molded biopolymer scaffold can then be received.