Preparation And Properties Of Zn-Cu Alloy Tissue Engineering Scaffold

In the field of bone tissue engineering,because zinc has a more suitable corrosion degradation rate than magnesium and iron and has good biocompatibility.It is expected to become a new generation of promising tissue engineering scaffold materials.Although zinc meets the basic requirements for tissue engineering scaffold materials.However,pure zinc has high density,poor mechanical properties,and low degree of matching with human bone mechanics.And implant materials are extremely prone to bacterial infections.The existence of these problems makes the practical application of zinc as a tissue engineering scaffold material still needs further research.In this study,copper was used as an alloying element.While improving the mechanical properties of pure zinc,it also controlled the corrosion degradation rate and endowed it with certain antibacterial properties.In this study,Zn-xCu(x=0,1,2,3)alloy tissue engineering scaffolds with the theoretical porosity of 60%and pore size ranging from150 to 300?m was prepared by the gas compression percolation method.Then the pore structure,microstructure,mechanical properties,in vitro degradation,antibacterial properties and cytotoxicity of four different copper content scaffolds were evaluated.Then the ZnO coating was prepared on the surface of the scaffold material by hydrothermal method.The ZnO coating improves the wettability of the surface of the material and realizes the functionalization of the surface of scaffolds.In addition,this paper also initially combined with the 3D printing technology to carry out the pore structure design,which provided a new method for the fabrication of zinc and zinc alloy tissue engineering scaffolds.The main conclusions of this article are as follows:(1)The prepared Zn-xCu(x=0,1,2,3)alloy tissue engineering scaffolds have uniform pore distribution and good connectivity between pores.The average pore size is 275?m.Compression mechanical performance tests show that the plateau stress?_y at 3%strain of the material is 2.55 to 51.15 MPa,and the elastic modulus E is 0.34 to 3.75 GPa.This is similar to the mechanical properties of human cancellous bone.The deformation of the scaffold is stable during the process of stress,and the shock absorption and energy absorption effect is obvious.(2)Simulated body fluid immersion experiments show that Zn-xCu(x=0,1,2,3)alloy tissue engineering scaffolds can well induce the deposition of Ca and P ions in simulated body fluids.The results of weight loss in immersion showed that Zn-3Cu had the fastest corrosion degradation,with an average daily weight loss of about 2.83 mg during 30 days of immersion.The amount of dissolved zinc is well below the human daily tolerance limit of 40 mg.The corrosion of the scaffold is mainly an electrochemical corrosion process,which is a typical component selective corrosion.(3)The antibacterial test results showed that:Zn-xCu(x=0,1,2,3)alloy tissue engineering scaffolds have obvious killing ability to E.coli and S.aureus.Cytotoxicity experiments showed that:the Zn-xCu(x=0,1,2,3)alloy scaffolds were immersed for 24 h in the extract and co-cultured with MC3T3 and L-929 for 24 h,the cell proliferation rate was above 80%,showing0??Grade cytotoxicity.After co-culture for 48 h,only L-929 cells showed grade?cytotoxicity to Zn-3Cu,and the rest showed grades 0??cytotoxicity.(4)The appearance of ZnO coating has improved the surface wettability of the material.The higher the copper content,the greater the thickness and density of the surface coating of the scaffold,and the better the wettability.The Zn-3Cu scaffold coated with ZnO was completely wetted.(5)The monomer obtained by the inverse calculation of the P function has the advantages of smooth surface transition and easy control of parameters,etc.,and is the most advantageous scaffold monomer model.The gypsum-salt turning mold prepared from the 3D printed polylactic acid scaffold can basically be formed,but still needs further improvement.