Preparation And Biological Safety Evaluation Of Polyhydroxyalkanoate/Tricalcium Phosphate Artificial Bone Scaffold By Fused Deposition

Background:In the clinical treatment,bone defect repair has been a major problem that puzzles the contemporary surgeon.Current,the commonly used treatment materials include autologous bone and allogeneic bone.The advantage of autologous bone is that there will be no rejection,but its source is very limited,and it will cause two damage to the patient.Although allogeneic bone has a lot of sources.However,there is the possibility of immune rejection,it can not be used in large numbers.However,with the development of computer aided design(CAD),3D printing technology and biomaterials,these technologies provide a new way to solve the above problems.Based on the above clinical problems,combined with CAD and fused deposition printing technology,use PHA and β-TCP as bioactive materials,preparation of artificial bone scaffold which has a porous structure.And through SEM,XRD,hardness test and biological safety test on the performance of the scaffold and evaluate the biological safety of the scaffold.Objective:1.To explore the effect of β-TCP content on the mechanical properties of PHA/β-TCP composites,crystallization and rheological properties.2.To explore the process conditions of PHA/β-TCP porous composite scaffolds,and to prepare porous scaffolds with good porosity and mechanical properties.3.To explore the biological safety of PHA/β-TCP composite scaffolds,and to provide scientific and theoretical basis for clinical trials.Methods:1.By melt blending method to prepare PHA/β-TCP composites with different content of TCP.And by using XRD,SEM,DSC,rheometer,the crystallization,mechanical and rheological properties of the composites were tested.2.Use SolidWorks computer aided design software,and build a three-dimensional cylindrical artificial bone scaffold,the internal pore structure of the scaffold design is neat,and between the inner hole and the hole are connected with each other,prepared PHA/β-TCP artificial bone scaffold which using FDM technology.By means of SEM,hardness test,compression test,porosity test,the basic properties of porous scaffolds were tested.3.The biological safety of PHA/β-TCP scaffold was tested by cytotoxicity test,systemic toxicity test,systemic subacute toxicity test and implant safety test.Conclusions:1.PHA is a typical ductile material,the addition of β-TCP significantly improved the tensile strength and elongation of PHA/β-TCP composite material,and the tensile strength and the elongation at break increases with the increase of the content of β-TCP increased first and then decreased;β-TCP in the PHA matrix as a nucleating agent,significantly increase the melting temperature of composite materials and the relative crystallization but,with the increase of the content ofβ-TCP,Tm and Xc composite increased first and then decreased;with the increase of β-TCP content,the apparent viscosity of the composites decreased first and then increased;with the increase of β-TCP content,the non Newton index material increased first and then decreased.2.PHA/β-TCP artificial bone scaffold was prepared by FDM technique under different β-TCP contents(5%wt,10%wt,20%wt,30%wt).By means of SEM,hardness test,compression test and porosity test,when the β-TCP content is 20%wt,the hardness and compressive strength of the PHA/P-TCP artificial bone scaffold reached a good level,and it can achieve good porosity.3.The testing of the PHA/β-TCP composite biological safety performance,the result is that PHA/β-TCP composites have no toxicity;systemic acute toxicity and subacute systemic toxicity test results showed that,in the experimental period the mice did not appear abnormal behavior and death,and the weight and the negative control group were consistent,indicating that PHA/β-TCP composites showed no acute systemic toxicity and subacute systemic toxicity;skin irritation test in experimental animal back without edema and erythema phenomenon,PHA/p-TCP composite without skin irritation on the experimental animal:after the PHA/β-TCP composite implantation,no inflammatory cells and fiber wrapped HE outbreak,the results show that the phenomena are self protective reaction matrix PHA/β-TCP,composite implant safety is good.In conclusion,PHA/β-TCP composite is a kind of safe material,which can be used in bone defect.