Preparation And Characterization Of Modified Nano-hydroxyapatite By Dual-phase Deposition

Nano-hydroxyapatite(n-HAp),as one of the most promising bioactive ceramics,has good biocompatibility and inhibits tumor growth.However,the antibacterial properties of nanohydroxyapatite are insufficient,and bacterial infections are prone to occur during implantation,which affects its clinical application.In this paper,a co-doping-dual-phase deposition duplex modification method combining zinc,silver,copper ion doping modification and nano zinc oxide,nano silver,nano copper surface deposition modification is used to improve the antibacterial effect of nano-hydroxyapatite performance.Zinc-doped,silver-doped,zinc-silver co-doped and copper-zinc co-doped nanohydroxyapatite were prepared by acid-base neutralization method.The type and quantity of doped ions and the pH of the reaction solution have an effect on phase composition,lattice structure,particle size and actual element incorporation of n-HAp,while they do not affect the microscopic morphology of n-HAp.In order to maintain a single phase n-HAp,the minimum threshold of the reaction solution pH is 9 when the doping amount of zinc or silver ion is 0.5-2mol%.When the co-doping amount of zinc and silver is 0.5-2.5mol%,and the co-doping amount of copper and zinc is 0.5-1.5mol%,the minimum threshold of the reaction solution pH increases to 9.5.The smaller the element doping amount and the higher the pH of the reaction solution,the easier it is for the product to maintain a single n-HAp phase.The lattice parameters of doped HAp have a non-monotonic relationship with the pH of the reaction solution and the amount of ion doping,while these parameters are also affected by the type of doped ions.In most cases,the theoretical doping amounts of zinc,silver and copper ions are larger than the actual doping amounts in the samples.In the co-doping system,zinc ions and copper ions are easily incorporated into the HAp lattice,whereas silver ions are more difficult to incorporate.Hydroxyapatite-copper-zinc oxide nanocomposites were fabricated using copper sulfate and zinc nitrate as the copper source and zinc source.The hydroxyapatite-copper-zinc oxide nanocomposite was gained by the process of depositing nano-zinc oxide and then depositing nano-copper or simultaneous deposition.The former had a better deposition effect.Meanwhile,the process of depositing nano-copper and then depositing nano-zinc oxide can only prepare hydroxyapatite-zinc oxide nano-composite.As the amount of copper source decreases,the deposited amount of nano-copper decreases and the morphology also changes.The co-doped copper-zinc treatment is beneficial for the subsequent deposition of nanocopper and nano-zinc oxide in the duplex co-doping-dual-phase deposition treatment process.The HAp-Ag-Zn O and HAp-Cu-Zn O nanocomposites obtained by the duplex treatment can significantly improve the antibacterial properties of the nano-hydroxyapatite,and the former has a stronger antibacterial ability.