Design and manufacture of combinatorial calcium phosphate bone scaffolds

It is well known that pore design is an important determinant of both the quantity and distribution of regenerated bone in artificial bone tissue scaffolds. A requisite feature is that scaffolds must contain pore interconnections on the order of 100-1000 m (termed macroporosity). Within this range, there is not a definitive optimal interconnection size. Recent results suggest that pore interconnections permeating the scaffold build material on the order of 2-20 m (termed microporosity) drive bone growth into the macropore space at a faster rate and also provide a new space for bone growth, proliferating throughout the interconnected microporous network. The effects of microstructural features on bone growth has yet to be fully understood. This work presents the manufacture and characterization of novel combinatorial test scaffolds, scaffolds that test multiple microporosity and macroporosity designs within a single scaffold. Scaffolds such as this can efficiently evaluate multiple mechanical designs, with the advantage of having the designs colocated within a single defect site and therefore less susceptible to experimental variation. This paper provides the manufacturing platform, manufacturing control method, and demonstrates the manufacturing capabilities with three representative scaffolds.