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.