Regularized phase tomography enables study of mineralized and unmineralized tissue in porous bone scaffold

Regularized phase tomography was used to image non-calcified fibrous matrix in in vitro cell-cultivated porous bone scaffold samples. 3D micro-architecture of bone and bone scaffold has previously been studied by micro-computed tomography, synchrotron radiation (SR) micro-computed tomography and microdiffraction. However, neither of these techniques can resolve the low-calcified immature pre-bone fibrous structures. Skelite porous scaffold discs were seeded with osteoblasts, a combination of osteoblast and pre-osteoclasts and, as controls, with pre-osteoclasts only, and then cultivated for 8 weeks. They were subsequently imaged using SR propagation-based phase contrast imaging. Reconstructions using a regularized holographic phase tomography approach were compared to standard (absorption) SR micro-computed tomography, which show that quantitative analysis, such as volume and thickness measurements, of both the calcified fraction and the immature bone matrix in the reconstructed volumes is enabled. Indications of the effect of this type of culture on Skelite, such as change in mineralization and deposit of mature bone on the walls of the scaffold, are found. The results are verified with a histological study.