Engineered bone from bone marrow stromal cells: a structural study by an advanced x-ray microdiffraction technique

The mechanism of mineralized matrix deposition was studied in a tissue engineering approach in which bone tissue is formed when porous ceramic constructs are loaded with bone marrowstromal cells and implanted in vivo. We investigated the local interaction between themineral crystals of the engineered bone and the biomaterial by means of microdiffraction, using a set-up based on an x-ray waveguide. We demonstrated that the newly formed bone is well organized inside the scaffold pore, following the growth model of natural bone. Combiningwide angle (WAXS) and small angle (SAXS) x-ray scattering with high spatial resolution, we were able to determine the orientation of the crystallographic c-axis inside the bone crystals, and the orientation of the mineral crystals and collagen micro-fibrils with respect to the scaffold. In this work we analysed six samples and for each of them two pores were studied in detail. Similar results were obtained in all cases but we report here only the most significant sample.