A medical device for prefabrication of large bone grafts in modern medicine.

Translating advances in the laboratory into sound clinical practice presents a series of formidable conceptual and technical challenges. One of them is our inability to maintain large grafts of living cells upon transfer from in vitro conditions into the host in vivo. This is due mainly to diffusion limitations within the grafting material. We embrace the well-known hypothesis of the "Diamond Concept" in bone tissue regeneration, which includes four key factors. Based on the understanding of basic elements of tissue engineering constructs, prefabrication and conditioning techniques and the nano-vascularisation of the scaffold, we furthermore hypothesize that combinations of cells, solid multipolymeric scaffold as the "core element" working as the extracellular matrix (ECM), growth factors and nano-vascularisation setting may eventually generate a large "ready-to-use"in vitro/in vivo graft. We are confident and think that growth factors will help in the construction of a step-by-step organisation of the bone tissue engineering construct (BTEC). A medical device, named in vitro/in vivo Bone Bioreactor Tissue Engineering Construct (IV2B2TEC), is proposed to fulfil the hypothesis. Soon, we hope to test the above hypothesis on a non-union bone defect in an animal model. This novel strategy will likely open new options for reconstructing extended bone defects and facilitate clinical translation of bone tissue engineering. As compared with conventional reconstructive methods, the strategy has four key advantages and might prove to be a novel armamentarium for clinicians in regenerative medicine.