No abstract

Musculoskeletal conditions are a major health concern in United States because of a large aging population and increased occurrence of sport-related injuries. The need for bone substitutes is especially important. Traditional treatments of bone-defect have many of limitations. Bone tissue engineering may offer a less painful alternative to traditional bone grafts with lower risk of infection. This research integrates biomimetic modeling, solid freeform fabrication (SFF), systems and control, and tissue engineering in one intelligent system for structured, highly porous biomaterials, which will be applied to bone scaffolds. Currently a new SFF-based fabrication system has been developed, which uses a pressurized extrusion to print highly biocompatible and water soluble sucrose bone scaffold porogens. To date, this system can build simple bone structures. In parallel we are utilizing a commercial rapid prototyping (RP) machine to fabricate thermoplastic porogens of various designs to determine the feasibility of injecting a highly viscous scaffold material into porogens. Materials which have been successfully used to make scaffolds by injection include calcium phosphate cement (CPC), molten poly-caprolactone (PCL), 90/10 and 80/20 (v/v %) composite of PCL and calcium phosphate (CaPO4,). Results presented for the injection method include characterization of attainable feature resolution of the RP machine, as well as preliminary cell-biomaterial interaction data demonstrating biocompatibility of CPC scaffolds. The preliminary results using a commercial rapid prototyping machine have demonstrated that the indirect porogen technique can improve 2–4 folds the resolution of SFF system in fabricating bone scaffolds. The resultant scaffolds demonstrate that the defined porous structures will be suitable for tissue engineering applications.