Capillary action: enrichment of retention and habitation of cells via micro-channeled scaffolds for massive bone defect regeneration.

The development of a biomaterial substitute that can promote bone regeneration in massive defects has remained as a significant clinical challenge even using bone marrow cells or growth factors. Without an active, thriving cell population present throughout and stable anchored to the construct, exceptional bone regeneration does not occur. An engineered micro-channel structures scaffold within each trabecular has been designed to overcome some current limitations involving the cultivation and habitation of cells in large, volumetric scaffolds to repair massive skeletal defect. We created a scaffold with a superior fluid retention capacity that also may absorb bone marrow cells and provide growth factor-containing body fluids such as blood clots and/or serum under physiological conditions. The scaffold is composed of 3 basic structures (1) porous trabecular network (300-400 μm) similar to that of human trabecular bones, (2) micro-size channels (25-70 μm) within each trabecular septum which mimic intra-osseous channels such as Haversian canals and Volkmann's canals with body fluid access, diffusion, nutritional supply and gas exchange, and (3) nano-size pores (100-400 nm) on the surface of each septum that allow immobilized cells to anchor. Combinatorial effects of these internal structures result in a host-adapting construct that enhances cell retention and habitation throughout the 3 cm-height and 4 cm-length bridge-shaped scaffold.