Several treatments have been developed for treating bone fractures as they are very common events. Amongst other new strategies, synthetic bone substitutes present a very high potential therapy because they lower the risk of infection and rejection. Moreover, bone progenitor cells have been added to these bone graft substitutes, allowing them to gain the property of osteogenesis. Surprisingly, it has been observed that bone formation was less efficient in the case of bone substitutes seeded with bone progenitor cells compared to cell-free bone substitutes. This result raised questions about the evolution of these cells inside the implant. In order to investigate this shortcoming, osteoprogenitor cells have been transfected using a GFP lentivirus. Using a viability assay and Alizarin and ALP stainings, the characterization of GFP-transfected bone progenitor cells demonstrated a phenotype unaltered after transfection with a lentivirus.