Preparation And Biological Properties Of TiO₂ Porous Coating With Embedded Cu Nanoparticles

Titanium and its alloy,which has small density,high strength,low elastic modulus and other good mechanical properties,are usually used to surgical instruments,implants,cardiovascular stents and other medical materials.However,there are still some shortcomings such as no antibacterial properties,poor biological activity,poor corrosion resistance and so on.This titanium and its alloy implanted in the body easily lead to implant infection,implant loosening and other issues,which are severely restricted titanium and titanium in clinical.Therefore,the preparation of bio-active coating with good antibacterial properties and excellent corrosion resistance has important clinical significance.In this paper,TiO₂ porous coating with different copper contents was prepared on the surface of pure titanium by adding 0,0.3 and 3.0g copper nanoparticles in the electrolyte using micro-arc oxidation technology.The structural characteristics,antibacterial,corrosion resistance and biological properties of the coatings were evaluated.The results are shown as follows:（1）Well separated pores homogeneously distributed over the surface of 0Cu,0.3Cu and 3.0Cu coatings prepared on the surface of pure titanium by micro-arc oxidation,ranging from a few nanometers up to 5μm in size.The coating thickness is 5 to 10 μm.The coating is mainly composed of anatase phase and pure titanium phase,and the copper contents of each coating are 0,1.3 and 2.76 at.%,Mainly in the form of nano copper and CuO.During the immersion days in phosphate buffer solution,Cu²⁺ were released from 0.3Cu and 3.0Cu coatings continously.Generally,the initial release rate is high and decreases with immersion time,3.0Cu release more Cu²⁺.（2）The antimicrobial properties of the coating on Staphylococcus aureus were evaluated by plate count,bacterial morphology and fluorescence staining.The results showed that 0.3Cu and 3.0Cu coatings had good antibacterial properties and the antibacterial rate was over 99%.0Cu coating without antibacterial properties,bacteria in the 0Cu surface can be normal growth and reproduction（3）The results of open circuit potential and polarization curve show that the corrosion resistance of pure titanium after micro-arc oxidation is obviously enhanced,and the incorporation of copper in coating has little effect on corrosion resistance.（4）3.0Cu coating had no obvious effect on the initial adhesion of MC3T3-E1 osteoblasts.However,3.0Cu coating showed higher cytotoxicity to osteoblasts after 1 day culture.0Cu and 0.3Cu coatings promote the proliferation and differentiation of osteoblasts,and promote the secretion of collagen on the surface of osteoblasts,accelerate the extracellular matrix mineralization,and promote the bone binding between the coating and the host bone.（5）Micro-arc oxidation coating can promote the proliferation and differentiation of ECs in human vascular endothelial cells and promote the secretion of NO and VEGF in the cells.With the increase of copper content in the coating,the activity of endothelial cells increased,the secretion of NO and VEGF also will increase.