Pore Structure Design And Performance Study Of Ti6Al4V Femoral Tissue Engineering Scaffold Based On Additive Manufacturing

The advent of tissue engineering technology provides a new solution for bone defects.The porous scaffold structure can provide adhesion and support to cells.Pore structure is one of the key factors of tissue engineering scaffolds,which directly affects the performance of scaffolds.But there is not a complete system to design the pore structure.The development of additive manufacturing provide a new method to process the tissue engineering scaffold,and it can greatly improve the controllability of pore structure.However,the technology of additive manufacturing is still not mature enough,and the performance of the specimen is still need to be tested.This paper is to design the porous structure of tissue engineering scaffolds with better biological properties based on Ti6Al4 V.Porous scaffolds were obtained by selective laser melting technology and their compressive mechanical properties were investigated.And the biological properties of Ti6Al4 V materials were obtained through cell culture experiments.To several square cell structures commonly used in tissue engineering scaffolds,we mainly consider pore size,porosity,surface area volume ratio and other factors,and use Ansys Workbench software to do mechanical simulation analysis.Two kinds of improved structure design and topology optimization design of square hole of scaffold are presented,and its carrying capacity is improved by 10%-20%.A preliminary design of femoral scaffold implant was made in this paper.In view of the difficulty of modeling the minimal surface structure,we use the additive plane method and the offset surface method to model the P surface,G surface and D surface.The comparison of the various aspects of the two modeling methods was made.The processing characteristics of the additive manufacturing equipment were obtained through experiments,and the scaffolds with different structures were obtained.The warping deformation,melt penetration,over melting,sticky powder and irregular flow in the forming process are analyzed.The influence of these phenomena on the performance of the scaffold was studied,and the mechanical properties of the irregular structure caused by melt penetration were analyzed.The relationship between the performance of the scaffold and porosity,cell size and pore shape was obtained through compression experiments.Two kinds of improved structure and topology optimization structure have been verified to improve their mechanical properties.At the same time,the moduli measurement error caused by the deformation of the pressing head of universal testing machine is analyzed.In order to improve the biological properties of Ti6Al4 V,alkali-heat treatment is used to process the materials.By observing the surface morphology of SEM,it is found that titanate precipitation occurs after treatment.The surface composition of the specimen was analyzed by XPS,and the surface was further oxidized by alkali-heat treatment.Contact angle measurement before and after alkali heat treatment is carried out.The results show that both of them have good hydrophilicity before and after treatment.And after treatment,the contact angle decreases and the hydrophilicity is further improved.The results of cell culture experiments showed that cells could adhere and proliferate on the surface of Ti6Al4 V material obtained by additive manufacturing method,and the material has good biological properties.