The influence of approaches for the purification of natural cancellous bone grafts: Morphology, microstructure, composition, strength and biocompatibility study

To find an optimal approach for preparation of porous scaffold for tissue engineering, natural cancellous bone were processed with several techniques: calcination, lyophilization, treatment of chemical reagents and supercritical CO2 fluid extraction, respectively. Scanning electron micrograph, energy dispersive X-ray microanalysis, X-ray diffraction, Micro-CT, mechanical test and T-cell proliferation assay were used to observe and compare morphology, microstructure, composition, mechanical strength and biocompatibility of the different scaffolds. After processing all the scaffolds exhibited natural porous three-dimension microstructure, and the composition and properties of natural bone, such as Ca/P ratio and hydroxyapatite crystal were still preserved in all of them. Except scaffolds processed with lyophilization, all the other scaffolds showed no influence on the proliferation of T-cell. And scaffolds processed with supercritical CO2 fluid performed higher compressive strength than that of the other scaffolds, which was similar to natural bones. As the consequence, supercritical CO2 fluid extraction may be a useful approach for preparation of natural scaffolds for tissue engineering.