In Vitro Study Of Constructing Tendon Stem Cell Composite Calf Freeze-dried Cancellous Bone Graft

Objective:In order to improve the technique for processing calf freeze-dried cancellous bone,accurately design the femoral head bone scaffold by digital model and load tendon stem cells into the self-developed perfusion bioreactor to induce osteogenic differentiation and for the regeneration material for femoral head necrosis.Methods:Micro CT data of the femoral heads of SD rats were segmented and reconstructed,and the femoral head bone scaffold models were designed.The modified calf freeze-dried cancellous bone processing method was used to numerically carve the fresh cancellous bone into the femoral head bone scaffold,and the enzyme digestion method was used for antigen-free freeze-drying.A 12-axis perfusion bioreactor model was designed and manufactured according to the femoral head bone scaffold models,and the models were 3D printed.SD rat tendon stem cells were isolated,extracted and expanded to the third generation for bioreactor loading,and induced osteogenesis using bone induction medium.Results:Compared with fresh cancellous bone of calf,freeze-dried cancellous bone of calf was more brittle and easy to be broken in small scale processing.The improved method of processing calf freeze-dried cancellous bone by first processing and then cell-free freeze-drying successfully solved the problem of fragmentation of calf freeze-dried cancellous bone at small scale processing.The machined femoral head bone brackets had an accuracy of less than 100?m.The self-designed bioreactor perfusion flow rate could reach the surface flow rate of 400-1000 ?m/s on the femoral head bone scaffold by optimizing the flow rate of osteogenesis and proliferation of tendon stem cells.The femoral head bone scaffold rich in tendon stem cells could be successfully induced to become bone.Conclusion:The numerical control processing technology of calf freeze-dried cancellous bone can produce bone scaffolds with natural trabecular anisotropy structure,which can be placed in a perfusion bioreactor,and tendon stem cells can proliferate and differentiate on its surface.This medical material may have the potential to treat femoral head necrosis.