Figure 2.

Selective cell retention. After harvesting, (a) the bone marrow is drawn through (b) an implantable graft matrix. This process facilitates matrix exposure to a high volume of bone marrow in a short time. The process is repeated until graft saturation is achieved. Several porous materials can be used as a graft matrix, e.g., demineralized bone matrix, cancellous bone chips, hydroxyapatite, and β-tricalcium phosphate. A higher fraction of mesenchymal progenitor cells are retained within the graft, whereas the retention of hematopoietic cells is significantly lower (c). After enrichment the graft is ready for implantation, although postprocessing procedures such as addition of whole bone marrow or platelet-rich plasma can be performed to improve graft handling properties and to improve the therapeutic potential of the graft. Figure was produced using Servier Medical Art (http://www.servier.com/servier-medical-art).