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The thesis aims to successfully fabricate NaHAp films doped separately and simultaneously with microelements: sodium, magnesium, strontium, fluorine, copper, silver and zinc on 316L stainless steel substrate to meet the requirement of screw bracing bone. Study on physicochemical characteristics, study on toxicity, antibacterial ability and bio-compatibility of NaHAp films separately and concurrently with trace elements.
VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY - Vo Thi Hanh SYNTHESIS AND CHARACTERIZATION OF TRACE ELEMENTS CO-DOPED HYDROXYAPATITE ON 316L STAINLESS STEEL APPLICATION IN BONE IMPLANT Major: Code: Theoretical and Physical Chemistry 62 440119 SUMMARY OF DOCTORAL THESIS IN CHEMISTRY Hanoi – 2018 The thesis has been completed at: Department of Corrosion and Protection of Metals - Institute for Tropical Technology - Vietnam Academy of Science and Technology Scientific Supervisors: Assoc Prof Dr Dinh Thi Mai Thanh, Institute for Tropical Technology Vietnam Academy of Science and Technology Reviewer 1: Reviewer 2: Reviewer 3: The thesis was defended at Evaluation Council held at Graduate University of Science and Technology - Vietnam Academy of Science and Technology on , 2018 Thesis can be further referred at: - The Library of Graduate University of Science and Technology - National Library of Vietnam INTRODUCTION The necessary of the thesis Nowadays, 316L stainless steel (316LSS), titanium and alloys of titanium are widely used in orthopedic surgery with the purpose of splinting bone Materials made of titanium and titanium alloy have a good mechanical properties and good biocompatibility but they have a high cost Therefore, in Vietnam, to reduce the cost of medical services, most of the splints are made of 316L stainless steel However, 316L stainless steel could be corroded and limited the ability of biological compatibility in the biological environment To improve these problems, 316LSS is generally coated biomaterials such as hydroxyapatite (Ca10(PO4)6(OH)2, HAp) HAp has chemical composition and biological activity similar to the natural bone HAp could stimulate the bonding between the host bone to implant materials and make bone healing ability faster Moreover, HAp also protects for the metal surfaces against corrosion and prevents the release of metal ions from the substrates into the environment However, pure HAp has been dissolved in the physiological environment which may lead to the disintegration of the coatings and affects the implant fixation These disadvantages could deal with doping some trace elements in the HAp structure by replacing Ca2+ ions with cations and substituting OHgroup with anions In addition, the present of trace element such as magnesium, sodium, strontium, fluorine, zinc … has also the role to stimulate the new bone formation and provides minerals for bone cells to grow Besides, the problem of postoperative infection should be concerned Thus, antibacterial elements such as copper, silver and zinc are also being studied to incorporated into HAp Based on the reasons mentioned above, the research topic of thesis is chosen as following: “Synthesis and characterizations of trace elements codoped hydroxyapatite coatings on 316L stainless steel application in bone implaint” The objectives of thesis: - Trace elements (sodium, magnesium, strontium, fluorine, copper, silver and zinc) doped NaHAp coatings are synthesized sucessfully on the 316LSS substrates, separately and simultaneously - Research on the physical and chemical characteristics, cytotoxicity and antibacterial ability, biological compatibility of the NaHAp coating doping some trace elements separately and simultaneously Research contents of the thesis: - Investigating and selecting of optimal conditions for the synthesis of NaHAp coatings and NaHAp coatings doping magnesium, strontium and fluorine separately and simultaneously by cathodic scanning potential method - Investigating and selecting of optimal conditions for the synthesis of NaHAp coatings doping copper, siliver and zinc separately and simultaneously by ion exchange method - The HAp coatings doping elements simultaneously: Mg, Sr, F, Na, Cu, Ag, Zn are studied to synthesize by the combination two methods: electrodeposition and ion exchange - Studying on the biological activity of materials: 316LSS, NaHAp/316LSS, MgSrFNaHAp/316LSS and HApđt/316LSS in simulated body fluid (SBF) solution - Studying on the cytotoxicity ability of powder: NaHAp, MgSrFNaHAp - Studying on antibacterial ability of powder: NaHAp, MgSrFNaHAp, AgNaHAp, CuNaHAp, ZnNaHAp HApđt - Evaluation of the biological compatibility of materials: 316LSS, NaHAp/316LSS, MgSrFNaHAp/316LSS on dog’s body CHAPTER OVERVIEW OF HAp AND DOPED HAp 1.1 The properties and synthesized methods of HAp and doped HAp coatings Some trace elements doped HAp coatings have more advantages than pure HAp coatings, such as: decrease of the dissolution, increase of the metabolism, antibacterial ability and compatibility HAp coatings is deposited on the substrates by many methods: plasma, magnetron and electrodeposition … These methods have advantages and disadvantages The electrodeposition has an important technology because of the advantages: the low temperature, easily controlling the coatings thickness, the high purity, high bonding strength and low cost of the equipment Furthermore, it is easy to substitute some trace elements ions (Mg2+, Na+, K+, Sr2+ and F- …) into HAp coatings by addiction M(NO3)n or NaX into the electrolyte Dope HAp is producted according to the chemical reaction: (10-x)Ca2+ + 6PO43- + (2-y)OH- + xM2+ + yX- Ca10-x M x(PO4)6(OH)2-yXy 1.2 In vitro and in vivo test of HAp The compatibility of materials is studied by immersion them in SBF solution and investigate the formation of apatite on the material surface Besides, the compatibility of materials is also studied by in vivio test on the animal 1.4 The application of HAp, doped HAp HAp and doped HAp are used as: - The medicine of calcium supplements: the composition of HAp contains a lot of calcium and be absorbed directly without transformation - Material for implantation: repair of the teeth and bone defects 1.5 The situation of HAp research in the country Basic on the overview of HAp and doped HAp, it can be seen that there is no published report about doped HAp coatings in our country; in the world, the trace elements doped HAp coatings have been only synthesized separately Thus, in this doctoral thesis, some trace elements (sodium, magnesium, strontium, fluorine, copper, silver and zinc) doped HAp coatings were synthesized separately and simultaneously The HAp obtained coatings have many good properties, such as: decrease of the dissolution and increase of the metabolism, antibacterial ability and compatibility for HAp coatings CHAPTER EXPERIMENT AND RESEARCH METHODS 2.1 Synthesis of doped HAp 2.1.1 By the electrodeposition method (cathodic scanning potential) 2.1.1.1 Electrochemical cells The electrodeposition was carried out in a three-electrode cell with 316LSS as the working electrode, platinum foil as the counter electrode and a saturated calomel electrode (SCE) as the reference electrode 2.1.1.2 Synthesis of NaHAp coatings - NaHAp coatings were synthesized on the 316LSS by cathodic scanning potential method in 80 mL solution containing Ca(NO3)2 3×10-2 M + NH4H2PO4 1.8×10-2 M and NaNO3 with different concentrations: 4.10-2 M (DNa1), 6.10-2 M (DNa2) 8.10-2 M (DNa3) - NaHAp coatings were synthesized under following conditions as follows: the different scanning potential ranges: to -1.5, to -1.7, to -1.9 and to -2.1 V/SCE; reaction temperatures: 25, 35, 50, 60 and 70 oC; pH = 4.0, 4.5, 5.0 and 5.5; scanning time: 1, 3, 5, and 10; scanning rate: 3, 4, 5, and mV/s 2.1.1.3 Synthesis of Mg2+, Sr2+ or F- doped NaHAp coatings (ĐNaHAp) ĐNaHAp were deposied at 50 oC in 80 mL solution containing at the Table 2.1 and under following conditions: the different scanning potential ranges: to -1.5, to -1.7, to -1.9 and to -2.1 V/SCE; scanning time: 1, 3, 5, and 10; scanning rate: 3, 4, 5, and mV/s Table 2.1 Chemical composition of the electrolyte ĐNaHAp MgNaHAp SrNaHAp Notation DMg1 DMg2 DMg3 DMg4 DSr1 DSr2 Chemical composition DNa2+ Mg(NO3)2 1x10-4 M DNa2+ Mg(NO3)2 5x10-4 M DNa2+ Mg(NO3)2 1x10-3 M DNa2+ Mg(NO3)2 5x10-3 M DNa2 + Sr(NO3)2 1x10-5 M DNa2 + Sr(NO3)2 5x10-5 M FNaHAp DSr3 DSr4 DF1 DF2 DF3 DNa2 + Sr(NO3)2 1x10-4 M DNa2 + Sr(NO3)2 5x10-4 M DNa2 + NaF 5x10-4 M DNa2 + NaF 1x10-3 M DNa2 + NaF 2x10-3 M 2.1.3.4 Synthesis of Mg2+, Sr2+ and F- co-doped NaHAp coatings (MgSrFNaHAp) MgSrFNaHAp were synthesized in 80 mL solution containing at DNa2 + NaF 2.10-3 M + Sr(NO3)2 5.10-5 M + Mg(NO3)2 1.10-3 M and under following conditions as follows: the different scanning potential ranges: to -1.5, to 1.7, to -1.9 and to -2.1 V/SCE; reaction temperatures: 25, 35, 50, 60 and 70 o C; scanning time: 3, 4, 5, 6, and 10; scanning rate: 3, 4, 5, and mV/s 2.1.2 By the ion exchange method Preparing material of NaHAp/316LSS: NaHAp coatings were synthesized on the 316LSS substrates by cathodic scanning potential method in the otimal condiction: the scanning potential range of to -1.7 V/SCE, the reaction temperatures of 50 oC, the scanning time of and the scanning rate of mV/s in 80 mL DNa2 solution 2.1.2.1 Synthesis of Cu2+, Ag+ or Zn2+ doped NaHAp coatings Material of NaHAp/316LSS with mass of 2.45x10-3 g was immersed in mL M(NO3)n solutions with variable concentration showed on Table 2.2 and at different time immersions: 0; 2.5; 5; 10; 20; 30; 60 and 80 minutes at room temperature Table 2.2 The initial concentration of Mn+ (mol/L) M(NO3)n Concentration (mol/L) Cu(NO3)2 0.005 0.01 0.02 0.05 0.1 AgNO3 0.0012 0.0022 0.005 0.01 Zn(NO3)2 0.01 0.05 0.1 0.15 2.1.2.2 Synthesis of Cu2+, Ag+ and Zn2+ co-doped NaHAp coatings CuAgZnHAp coatings was synthesized by the way: immersion the material of NaHAp/316LSS about 30 minutes at room temperature in mL solutions containing simultaneously: Cu(NO3)2 0.02 M + AgNO3 0.001 M + Zn(NO3)2 0.05 M 2.1.3 Synthesis of Mg2+, Sr2+, Na+, Cu2+, Ag+, Zn2+ and F- co-doped HAp coatings (HApđt) - Preparing material of MgSrFNaHAp/316LSS: MgSrFNaHAp coatings were synthesized on the 316LSS substrates by cathodic scanning potential method in the otimal condiction: the scanning potential range of to -1.7 V/SCE; reaction temperatures of 50 oC; scanning time of 5; scanning rate of mV/s in 80 mL the solution containing: DNa2 + NaF 2.10-3 M + Sr(NO3)2 5.10-5 M + Mg(NO3)2 1.10-3 M - HApđt coatings was synthesized by the way: immersion the material of MgSrFNaHAp/316LSS about 30 minutes at room temperature in 4mL solutions containing simultaneously: Cu(NO3)2 0.02 M + AgNO3 0.001 M + Zn(NO3)2 0.05 M 2.2 Research method 2.2.1 Electrochemical method Methods of scanning potential, potential applied, open circuit potential and electrochemical impedance spectra which were carried out on AUTOLAB equipment at Institute for tropical Technology 2.2.2 Ion exchange method Ion exchange was done by immersing the meterial of NaHAp/316LSS or MgSrFNaHAp/316LSS in solution containing Mn+ with different concentrations 2.2.3 Coatings characterization The composition and structure of doped HAp obtained coatings were analyzed by the method: IR, XRD, SEM, AFM, EDX (or AAS or ICP-MS), UV-VIS Physical properties of the coatings was determined by: mass, thickness, adhesion strength The dissolution behavior of the coatings were studied by measuring the concentration of Ca2+ dissolved from the coatings and iron released from 316LSS substrates when the samples immersed into the 0.9 % NaCl solution or SBF solution 2.2.5 In vitro and in vivo Test 2.2.5.1 Invitro test in simulated body fluid (SBF) solutions The in vitro tests in SBF solution investigated by the apatite formed ability and the protection substrates ability of meterials and using the method: open circuit potential (OCP), electrochemical impedance measurements at the OCP and the polarized Tafel curves 2.2.5.2 Cytotoxicity ability test The safety and biocompatibility of NaHAp and MgSrFNaHAp powder were tested on fibroblasts cells by two methods: the Trypan Blue and the MTT 2.2.5.3 Antibacterial ability test The antibacterial ability of NaHAp, MNaHAp, MgSrFNaHAp and HApđt powder were tested on three strains: E.faecalis, E.coli, C.albicans P.aerugimosa by the disk diffusion agar method 2.2.5.4 In vivo test Healthy dogs are divided to groups, each group of dogs, which are implanted with splint made of: 316LSS, NaHAp/316LSS and MgSrFNaHAp/316LSS by two methods: implantation the materials on the thigh and on the femur The material compatibility is evaluated by observation of the situation the incision, the general images and the microscope images at transplant location CHAPTER RESULTS AND DISCUSSION i (mA/cm ) 3.1 Synthesis and characterization of doped HAp coatings 3.1.1 Electrodeposition of doped HAp coatings 3.1.1.1 NaHAp coatings a The cathodic polarization curve The cathodic polarization curve of 316LSS substrates at the potential range ÷ -2.1 V/SCE are shown in Figure 3.1 With this potential range, there are several electrochemical reactions, such as: 2H+ + 2e- H2 (3.1) O2 + 2H2O + 4e 4OH (3.2) 3 H PO4 + 2e PO4 + H2 (3.3) 2 H2 PO4 + 2e HPO4 + H2 (3.4) HPO24 + 2e- PO34 + H2 (3.5) NO3 + 2H2O + 2e NO2 + 2OH (3.6) 2H2O + 2e H2 + 2OH (3.7) 2 H PO4 + OH HPO4 + H2O (3.8) HPO24 + OH- PO34 + H2O (3.9) 3 2+ + − 10(Ca , Na ) + PO4 + 2OH → (Ca, Na)10(PO4)6(OH)2 (3.10) 0.0 -0.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0 -5.5 -6.0 -2.2 -2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 E (V/SCE) Figure 3.1 The cathodic polarization curve of 316LSS substrates in the DNa2 solution b Effect of Na+ concentration The ratio of (Ca+0.5Na+Mg)/P in all obtained coatings samples at DNa1, DNa2 and DNa3 solutions is the same the ratio of Ca/P in the natural bone (1.67) (Table 3.1) However, to reach the Na/Ca ratio similar to its in natural bone, the deposited NaHAp coatings in the DNa1 and DNa2 solution are suitable Therefore, DNa2 was chosen for the next experiments Table 3.1 The component of elements of NaHAp deposited on 316L SS in DNa1, DNa2 and DNa3 solutions Weigh (%) DD Na / Ca (0.5 Na+ Ca)/ P P Ca Na DNa1 17.25 36.09 0.32 0.0155 1.63 DNa2 16.80 33.20 1.50 0.0785 1.61 DNa3 16.60 33.09 2.20 0.1156 1.58 3- PO4 2- CO3 3500 447 603 Intensity PO4 874 1384 11 1 1 1 566 NaHAp HAp (NIST) 1036 4000 (a) 3- OH 1641 H2O 3441 Tranmistance (a.u) - CO3 2- HAp; CrO.FeO.NiO; Fe 3000 2500 2000 1500 1000 500 10 -1 Wave number (cm ) 20 30 40 50 60 70 degree Figure 3.2 IR spectra and XRD patterns of NaHAp deposited in DNa2 solution Both IR spectra and XRD patterns of NaHAp deposited in DNa2 solution exhibit that NaHAp coatings have crystals structure and single phase of HAp (Figure 3.2) c Effect of the scanning potential range The charge, mass, thickness and adhesion strength of NaHAp coatings at the different potential ranges show that the thickness and adhesion strength of NaHAp coatings reaches the maximum value at potential range of ÷ -1.7 V/SCE (Table 3.2) Thus, the potential range to -1.7 V/SCE is chosen for NaHAp coatings electrodeposition Table 3.2 The variation of charge, mass, thickness and adhesion strength of obtained NaHAp coatings at the different scanning potential ranges Scanning potential ranges Charge Mass Thickness Adhesion (V/SCE) (C) (mg/cm ) (àm) (MPa) ữ -1.5 0.41 1.00 3.2 ÷ -1.7 3.23 2.45 7.8 7.2 ÷ -1.9 4.29 1.82 5.8 7.1 ÷ -2.1 6.57 1.67 5.3 7.0 d Effect of electrodeposition temperature The SEM images of NaHAp coatings deposited in DNa2 at different temperatures show that the temperature have an effected on the morphology of obtained coatings The XRD diffraction data of NaHAp coatings at the different temperatures are shown in Figure 3.4 The typical peaks of the 316LSS substrates were observed in all samples At 25 and 35 oC, the obtained coatings is mostly dicalcium phosphate dehydrate (CaHPO4.2H2O, DCPD) with the typical peaks at 2 12o and 24o With temperature from 50°C, the peaks of DCPD are not detected and there are only characteristic peaks of HAp phase at 2 26o (002), 32o (211), 33o (300), 46o (222) and 54o (004) Thus, 50 oC is chosen to prepare NaHAp coatings Figure 3.3 The SEM images of deposited NaHAp coatings at different temperatures 34 HAp; DCPD CrO.FeO.NiO; Fe 1 Intensity 60 C 50 C 35 C 25 C 10 20 30 40 50 60 70 degree Figure 3.4 XRD patterns of NaHAp deposited at different temperatures e Effect of pH Results of mass and thickness of NaHAp coatings with pH solusions from 4.0 to 5.5 show on table 3.3 The results indicate that their values reaches the highest value at pH0=4.5 Thus, pH0 is chosen for NaHAp coatings electrodeposition Table 3.3 The variation of mass and thickness of obtained NaHAp coatings at pH solutions difference pH 4.0 4.5 5.0 5.5 Mass of NaHAp coatings (mg/cm ) 2.05 2.43 1.54 1.31 Thickness of NaHAp coatings (µm) 6.55 7.80 4.92 4.19 g Effect of the scanning times The charge, mass, thickness and adhesion strength of NaHAp coatings at the different scanning times show that the thickness and adhesion strength of NaHAp coatings are highest at scanning times (Table 3.4) Table 3.4 The variation of charge, mass, thickness and adhesion strength of obtained NaHAp coatings at the different scanning times Scanning times (times) Charge (C) Mass (mg/cm2) Thickness (µm) Adhesion (MPa) Table 3.7 The atomic ratios of X/Ca, Y/P and the formula of ĐNaHAp coatings The formula (expectation) DD Na/Ca X/Ca Y/ P -3 DMg1 0.062 2.90x10 1.59 Ca9.403Mg0.027Na0.570(PO4)6(OH)2 -3 DMg2 0.056 5.70x10 1.58 Ca9.438Mg0.052Na0.510(PO4)6(OH)2 -3 DMg3 0.060 9.60x10 1.54 Ca9.378Mg0.086Na0.536(PO4)6(OH)2 -2 DMg4 0.056 1.95x10 1.50 Ca9.352Mg0.168Na0.480(PO4)6(OH)2 -4 DSr1 0.065 1.74x10 1.64 Ca9.403Sr0.002Na0.595(PO4)6(OH)2 -4 DSr2 0.061 3.68x10 1.59 Ca9.447Sr0.003Na0.549(PO4)6(OH)2 -4 DSr3 0.0605 6.30x10 1.57 Ca9.457Sr0.006Na0.537(PO4)6(OH)2 -3 DSr4 0.049 1.00x10 1.58 Ca9.469Sr0.009Na0.521(PO4)6(OH)2 -2 DF1 0.052 5.50x10 1.66 Ca9.508Na0.492(PO4)6(OH)1.477F0.523 -2 DF2 0.070 7.40x10 1.67 Ca9.326Na0.674 (PO4)6(OH)1.293F0.707 -2 DF3 0.099 9.90x10 1.67 Ca9.085Na0.915(PO4)6(OH)1.097F0.903 (X/Ca = Mg/Ca or Sr/Ca or F/Ca; Y/P = (0,5Na+ Ca + Mg + Sr)/P) b The effect of scanning potential range Table 3.8 shows that the scanning potential range of ÷ -1.7 V/SCE for MgNaHAp + SrNaHAp and at ÷ -1.8 V/SCE for FNaHAp, the mass, thickness and adhension strength of obtained ĐNaHAp coatings are best Thus, the scanning potential range of ÷ -1.7 V/SCE is selected to synthesize the MgNaHAp + SrNaHAp coatings and ÷ -1.8 V/SCE for FNaHAp coatings Table 3.8 The variation of charge, mass, thickness and adhesion strength of deposited ĐNaHAp coatings at the different scanning potential ranges Scanning ĐNaHAp potential ranges (V/SCE) ÷ -1.5 ÷ -1.7 MgNaHAp ÷ -1.9 ÷ -2.1 ÷ -1.5 ÷ -1.7 SrNaHAp ÷ -1.9 ÷ -2.1 ÷ -1.6 ÷ -1.7 FNaHAp ÷ -1.8 ÷ -1.9 Charge Mass Thickness (C) (mg/cm ) (µm) 0.42 3.56 4.52 6.85 0.31 3.51 4.32 6.69 0.50 3.63 4.25 4.97 1.21 2.63 1.96 1.41 1.12 2.35 1.91 1.45 1.40 2.40 2.90 1.80 11 5.5 8.1 6.3 4.5 5.2 7.6 6.1 4.7 4.2 7.8 8.3 5.4 Adhesion (MPa) 7.3 7.2 7.1 7.0 7.4 7.3 7.1 7.0 7.6 7.1 6.9 5.5 3- 2- PO4 3- CO3 PO4 - OH CO3 H2O F 11 FNaHAp Intensity 874 NaHAp 2500 2000 1500 -1 Wave number (cm ) 602 MgNaHAp 1000 565 1035 1390 3445 3000 SrNaHAp 437 MgNaHAp 3500 SrNaHAp 4000 23 HAp; CrO.FeO.NiO; Fe - 1645 Tranmistance (a.u) FNaHAp 2- c The effect of the scanning times The results of the mass and thickness of ĐNaHAp coatings at the different scanning times show on Table 3.9 The mass, thichness and adhesion strength of deposited ĐNaHAp coatings at scanning times are higher than othes scanning times so scanning times is chosen to deposited the ĐNaHAp coatings Table 3.9 The variation of charge, mass, thickness and adhesion strength of deposited ĐNaHAp coatings at the different scanning times Scanning Charge Mass Thickness Adhesion ĐNaHAp times (C) (mg/cm ) (µm) (MPa) 0.76 0.57 1.6 2.40 1.72 5.5 7.3 MgNaHAp 3.51 2.63 8.1 7.2 4.61 1.41 4.5 6.3 10 6.33 0.98 3.1 5.7 0.56 0.37 1.2 2.13 1.51 5.2 10.0 SrNaHAp 3.51 2.35 7.6 7.3 4.02 1.51 4.8 7.5 10 4.98 1.12 3.7 5.2 0.78 0.62 1.8 2.61 1.80 5.6 7.4 FNaHAp 3.82 2.40 7.8 7.1 5.14 1.52 4.9 6.1 10 6.96 1.26 4.1 5.8 d Characterization of ĐNaHAp coatings The analysed results of IR spectra, XRD patterns and SEM images show that deposited ĐNaHAp coatings have crystals structure and single phase of HAp (Figure 3.7) and the morphology change because of the presence of Mg, Sr or F into NaHAp coatings (Figure 3.8) NaHAp 500 10 15 20 25 30 35 40 45 50 55 60 65 70 degree Figure 3.7 IR spectra and XRD patterns of ĐNaHAp coatings 12 Figure 3.8 SEM images of NaHAp and ĐNaHAp coatings 3.1.1.3 Synthesis of Mg2+, Sr2+and F- co-doped NaHAp coatings (MgSrFNaHAp) a The effect of the scanning potential range The MgSrFNaHAp coatings is produced on the cathode substrates according to the chemical reaction: 10(Ca2+,Na+,Mg2+,Sr2+) + PO34 + 2OH- (Ca,Na,Mg,Sr)10(PO4)6(OH)2 (3.15) (Ca,Na,Mg,Sr)10(PO4)6(OH)2 + x F- + x H+ (Ca,Na,Mg,Sr)10(PO4)6(OH)2- xFx + xH2O (3.16) The change of charge, mass, thickness and adhesion strength of MgSrFNaHAp coatings with the different potential ranges shows on Table 3.10 The mass and thickness of MgSrFNaHAp coatings are highest at ÷ -1,7 V/SCE Table 3.10 The variation of charge, mass, thickness and adhesion strength of deposite MgSrFNaHAp coatings with the different scanning potential ranges Scanning potential Charge Mass Thickness ranges (V/SCE) (C) (mg/cm ) (àm) ữ -1.5 1.13 1.01 3.1 ÷ -1.7 4.32 3.17 8.9 ÷ -1.8 5.08 2.54 7.8 ÷ -1.9 5.92 1.95 5.9 ÷ -2.1 7.84 1.47 4.2 SEM images of MgSrFNaHAp coatings deposited with different potential ranges are presented in Fig 3.9 With potential ranges of ÷ -1.7 ÷ -1.8 V/SCE, the deposited coatings are denser with cylinder shapes Therefore, the potential ranges of ÷ -1,7 V/SCE is selected to electrodeposited MgSrFNaHAp coatings Figure 3.9 SEM images of MgSrFNaHAp coatings deposited with the potential ranges: (a) ÷ -1,5; (b) ÷ -1,7; (c) ÷ -1,8; (d) ÷ -1,9 (V/SCE) 13 b Effect of electrodeposition temperature At 25 and 35 oC, the deposited coatings are mostly DCPD With higher temperature, the peaks of DCPD are not detected and there are only peaks of HAp phase (Figure 3.10a) Thus, 50 oC is chosen to prepare MgSrFNaHAp coatings c The effect of the scanning times The XRD patterns indicate that the phase of deposited coatings at one scanning times is only DCPD without HAp At scanning times, it appears the phase of HAp but DCPD is still the mainly component From scanning times, the obtained coatings have single phase of HAp (Figure 3.10b) Thus, scanning times is chosen for MgSrFNaHAp coatings electrodeposition d Effect of the scanning rate Figure 3.10c presents the XRD patterns of MgSrFNaHAp coatings deposited at different scanning rates Both XRD patterns exhibit the hydroxyapatite phase with the typical peaks at 2 of 32o and 26o However, with the scanning rate at 6, mV/s, there are also appear peaks of DCPD at 2 of 12o Thus, scanning rate mV/s is chosen to deposite of MgSrFNaHAp coatings 1 HAp; DCPD; CrO.FeO.NiO; Fe (c) 1 70 C Intensity 60 C 1 13 lÇn quÐt 50 C 1 10 lÇn quÐt lÇn quÐt Intensity 34 1 HAp; DCPD; CrO.FeO.NiO; Fe 34 (b) HAp; DCPD; CrO.FeO.NiO; Fe 11 mV/s Intensity (a) mV/s mV/s 2 lÇn quÐt mV/s 35 C mV/s lÇn quÐt 25 C 10 20 30 40 degree 50 60 70 10 20 30 40 degree 50 60 70 10 20 30 40 degree 50 60 Figure 3.10 XRD patterns of deposited coatings with the change: (a) temperature, (b) scanning time, (c) scanning rate e Characterization of MgSrFNaHAp coatings The EDX spectra of MgSrFNaHAp coatings shows that: the presence of main elements doped in HAp including: Ca, O, P, Mg, Na, F and Sr (Table 3.11) These results have been used to calculate the atomic ratios of M/Ca, (Ca + M)/P (Table 3.12) The ratios suggest that the components of the elements in the coatings are similar to component of mineral phase in natural bone Table 3.11 The element component of MgSrFNaHAp coatings deposited on 316L SS Elements O Ca P Na Sr Mg F Weigh (%) 39.34 32.65 15.76 0.56 0.03 0.14 1.50 Atomic (%) 68.20 18.00 11.20 0.99 0.01 0.13 1.47 14 70 Table 3.12 The atomic ratios of M/Ca and M/P in MgSrFNaHAp coatings and in natural bone M/Ca (M: Na, Mg, Sr, F) MgSrFNaHAp In natural bone -2 Na/ Ca 8.8×10 0.102 -3 Mg/Ca 1.2ì10 6.7ì10-3ữ 1.7ì10-2 Sr/ Ca 8.9ì10-4 2.7ì10-4 ữ 9.8ì10-4 F/ Ca 1.3ì10-2 0.024 ữ 0.15 (0,5 Na + Mg + Sr + Ca)/P 1.664 SEM and AFM images of deposited coatings are shown in Figure 3.11 At the same conditions, MgSrFNaHAp coatings with the presence of Mg, Sr, F are high density, uniform and has a rod shape, while HAp coatings has a plate shape The roughness value (Ra) of MgSrFNaHAp coatings is less times than its of NaHAp coatings Figure 3.11 SEM (a) and AFM (b) images of NaHAp and MgSrFNaHAp coatings 3.1.2 Synthesis of doped HAp by ion exchange method 3.1.2.1 Synthesis of Cu2+, Ag+ or Zn2+ doped NaHAp coatings a Effects of M2+ concentration For the ion exchange between HAp and Cu2+, the initial concentration of Cu2+ increases from 0.005 M ÷ 0.02 M, the ion exchange capacity rises rapidly When the concentration of Cu2+ was elevated to 0.05 M and 0.1 M, the capacity altered slightly, as the ion exchange process had reached trace of the equilibrium Therefore, 0.02 M Cu2+ solution is used to synthesize CuHAp coatings (Table 3.13) For ion exchange between HAp coatings with Ag+ and Zn2+ ions, ion exchange capacity increased simutaneously as Ag+ and Zn2+ concentration increased Xray diffraction of the obtained samples after ion exchange are presented in Fig With concentration of Ag+ from 0.001 M to 0.005 M and Zn2+ from 0.01 M to 0.1 M, all the samples have crystals structure and single phase of HAp Contrary, with the Ag+ concentration of 0.01 M, the obtained coatings have mainly the phase of Ag3PO4 Therefore, 0.001 M Ag+ and 0.05 M Zn2+ solutions are used to synthesize AgHAp and ZnHAp coatings 15 Table 3.13 Ion exchange capacity and the formula of MHAp Ion Cu2+ Ag+ Zn2+ Concentration Mn+ (M) 0.005 0.01 0.02 0.05 0.1 0.001 0.002 0.005 0.01 0.01 0.05 0.1 The formula MNaHAp (expectation) Ca9.278Na0.722 Cu0.065(PO4)6(OH)2 Ca9.162Na0.722 Cu0.116(PO4)6(OH)2 Ca9.113Na0.722 Cu0.165(PO4)6(OH)2 Ca9.076Na0.722 Cu0.202(PO4)6(OH)2 Ca9.064Na0.722 Cu0.214(PO4)6(OH)2 Ca9.021Na0.722 Ag0.257(PO4)6(OH)2 Ca8.907Na0.722 Ag0.371(PO4)6(OH)2 Ca8.714Na0.722 Ag0.564(PO4)6(OH)2 Ca8.783Na0.722 Zn0.495(PO4)6(OH)2 Ca8.040Na0.722 Zn1.238(PO4)6(OH)2 Ca5.452Na0.722 Zn3.826(PO4)6(OH)2 Q (mmol/g) 0.065 0.117 0.166 0.204 0.216 0.259 0.374 0.569 2.470 0.499 1.248 3.858 HAp; CrO.FeO.NiO; Fe; Ag 3PO4 4 4 g Intensity 23 4 4 f e d c b a 10 15 20 25 30 35 40 45 50 55 60 65 degree Figure 3.12 XRD patterns of the obtained samples after ion exchange between HAp and solution containing: 0.01 M Zn2+ (a), 0.05 M Zn2+ (b), 0.1 M Zn2+ (c) and 0.001 M Ag+ (d), 0.002 M Ag+(e), 0.005 M Ag+ (f), 0.01 M Ag+ (g) b Effect of contact time The change in ion exchange capacity folowing the contact time are presented in Fig The results show that: after 10 minutes contact with Ag+ ion and after 30 minutes contact with Cu2+ or Zn2+, the ion exchange capacity has reached equilibrium trace (figure 3.13); if the contact time is longer, this value changes light Thus, the contact time is selected to synthesize CuNaHAp or ZnNaHAp of 30 minutes and AgNaHAp coatings of 10 minutes 16 0.55 0.45 + 0.16 0.50 0.15 0.14 0.13 0.40 0.35 + NaHAp + Ag 0,001M 2+ NaHAp + Cu 0,02M 0.12 1.4 1.2 2+ 0.17 1.6 Q (mmol Zn /g NaHAp) 0.60 0.18 Q (mmol Ag /g NaHAp) 2+ Q (mmol Cu /g NaHAp) 0.19 1.0 0.8 0.6 2+ NaHAp + Zn 0,05M 0.30 10 20 30 40 50 60 70 80 90 10 20 Time (min) 30 40 50 60 70 80 90 10 20 30 40 Time (min) 50 60 70 80 90 Time (min) Figure 3.13 The change in ion exchange capacity of the HAp coatings with Mn+ solutions c Characterization of CuNaHAp, AgNaHAp, ZnNaHAp coatings CuHAp Intensity 1390 AgHAp (a) 1 PO4 3- PO4 H2O Tranmistance (a.u) 3- CO3 - OH HAp; CrO.FeO.NiO; Fe 2- NaHAp 11 ZnNaHAp AgNaHAp ZnHAp CuNaHAp 1643 3430 602 565 NaHAp 1034 4000 3500 3000 2500 2000 1500 1000 500 10 -1 Wave number (cm ) 20 30 40 degree 50 60 Figure 3.14 IR spectra and XRD patterns of NaHAp and MNaHAp coatings Both IR spectra and XRD patterns of MNaHAp coatings exhibit that NaHAp coatings have crystals structure and single phase of HAp (Figure 3.14) SEM images of HAp and MHAp coatings show that with the present of Cu, Ag, Zn in HAp structure, the morphology changes from plate shape of HAp to rod shape of CuHAp; fiber shape of AgHAp and coral-shape of ZnHAp (Figure 3.15) Figure 3.15 SEM images of NaHAp and MnaHAp coatings 3.1.2.2 Synthesis of Cu2+, Ag+ and Zn2+ co-doped NaHAp coatings The ion exchange capacity of NaHAp coatings with the solution containing simultaneously: Cu2+ 0.02 M + Ag+ 0.001 M + Zn2+ 0.05 M at 30 minutes is smaller than its with the solution containing separately: Cu2+ 0.02 M or Ag+ 0.001 M or Zn2+ 0.05 M (Table 3.14) Table 3.14 The ion exchange capacity and the fomular of CuAgZnNaHAp coatings Ion Cu2+ Concentration Mn+ (M) 0.02 Q (mmol/g) 0.121 17 The formula MNaHAp (expectation) Ca8.550Na0.722 Cu0.121 Ag+ 0.001 0.207 Ag0.208Zn1.121(PO4)6(OH)2 2+ Zn 0.05 1.117 Results of IR spectra, XRD patterns and SEM images demonstrate that CuAgZnNaHAp obtained coatings have crystals structure with slate shape and single phase of HAp (Figure 3.16) HAp; CrO.FeO.NiO; Fe 1 1390 Intensity Tranmistance (a.u) (a) 1643 (b) 3432 602 565 2 1 (b) (a) 1034 4000 3000 2000 -1 Wave number (cm ) 1000 10 15 20 25 30 35 40 45 50 55 60 65 degree Figure 3.16 IR spectra and XRD patterns of NaHAp (a) and CuAgZnNaHAp (b) coatings and SEM images of CuAgZnNaHAp coatings 3.1.3 Synthesis of Mg2+, Sr2+, Na+, Cu2+, Ag+, Zn2+ and F- co-doped HAp coatings (HApđt) The EDX spectra of HApđt coatings obtained shows that: There are the presence of 10 main elements doped in HAp, including: Ca, O, P, Mg, Na, F, Sr, Cu, Ag and Zn with their components listed at table 3.15 The atomic ratios of X/Ca and (0,5Na+Ca+Mg+Sr+Cu+0,5Ag+Zn)/P (symbol Z/P) are calculated and show on Table 3.16 To compare with component of mineral phase in natural bone, the element components of Mg, Sr, F and Na in the coatings are similar to but this values of Cu, Ag and Zn and Na are higher to increase the antibacterial ability of the coatings Table 3.15 The element component of HApđt coatings Elements O P Ca Na Mg Sr F Cu Ag Zn Weigh (%) 29.01 14.67 52.83 0.15 0.04 0.03 1.07 0.18 0.39 1.06 Atomic (%) 49.17 12.63 35.82 0.18 0.05 0.008 1.53 0.08 0.1 0.44 Table 3.16 The atomic ratios of X/Ca and Z/P in HApđt coatings and in natural bone The atomic F/Ca Mg/Ca Sr/Ca Na/Ca Cu/Ca Ag/Ca Zn/Ca Z/P ratios HApđt 0.0646 2x10-3 4x10-4 8x10-3 3x10-3 4x10-3 0.0187 1.65 coatings Natural bone 0.149 0.176 4x10-4 0.102 1x10-4 1x10-6 6x10-4 1.67 The fomular Ca9.005Mg0.019Sr0.004F0.638Cu0.032Ag0.041Zn0.185Na0.074(PO4)6(OH)2 (expectation) IR spectra, XRD patterns and SEM images of HApđt obtained coatings demonstrate that they have crystals structure with slate shape and single phase of HAp (Figure 3.17) 18 HAp; CrO.FeO.NiO; Fe (a) 1390 1643 (b) 1 (b) 1 Intensity Tranmistance (a.u) 3432 (a) 602 565 1034 4000 3000 2000 -1 Wave number (cm ) 10 1000 15 20 25 30 35 40 45 degree 50 55 60 65 Figure 3.17 IR spectra and XRD patterns of NaHAp (a) and HApđt (b) coatings and SEM images of HApđt coatings The dissolution behaviors of HApđt, MgSrFNaHAp and NaHAp coatings is studied by immersions materials in 0.9% NaCl and SBF solutions For all samples, the dissolved amount of Ca2+ ions from these coatings increases with immersion time However, The dissolution of HApđt coatings is slowest and of NaHAp is faster at any time (Figure 3.18a) The release concentration of iron ions from substrates increases according to time for all sample Because HApđt coatings play as a barrier to protect the substrates and the dissolution of the coatings decreases with the presence of the trace elements in HAp structure so the iron ion release is arranged in order: 316LSS > NaHAp/316LSS > MgSrFNaHAp/316LSS > HApđt/316LSS This suggested that the protect ability for the substrates of the coatings: HApđt > MgSrFNaHAp > NaHAp 200 a: NaHAp/TKG316L b: MgSrFNaHAp/TKG316L c: HAp®t /TKG316L a Concentration Fe (ppb) 2+ Concentration Ca (ppm) b c 150 a: TKG316L b: NaHAp/TKG316L c: MgSrFNaHAp/TKG316L d: HAp®t /TKG316L a b 100 c d 50 2 10 12 14 16 18 Time (days) 14 21 28 Time (days) Figure 3.18 The release concentration of Ca2+ (1) and Fen+ (2) 3.2 The in vitro and in vivo test 3.2.1 The in vitro test 3.2.1.1 Invitro test in simulated body fluid (SBF) solutions a The variation of the pH and the open circuit potential (OCP - Eo) value With 316LSS sample, the pH solution decreases and Eo tends to increase during immersion time (Figure 3.19) 19 8.2 7.6 80 E0 (V/SCE) 7.8 7.4 pH 7.2 7.0 (a) (b) (c) 6.8 6.6 (d) (c) 40 (b) -40 (a) -80 -120 (d) 6.4 (a): TKG316L (b): NaHAp/TKG316L (c): MgSrFNaHAp/TKG316L (d): HAp®t/TKG316L 120 (a): TKG316L (b): TKG316L/NaHAp (c): TKG316L/MgSrFNaHAp (d): TKG316L/HApdt 8.0 -160 6.2 10 15 20 25 Time (days) 10 12 14 Time (days) 16 18 20 22 Figure 3.19 The variation of pH (1) and Eo (2) vs different immersion times in SBF solution With doped HAp/316LSS materials, pH solution and value of Eo have fluctuated which shows the formation of new apatite crystals or the dissolution of the coatings in the immersion process The dissolution HAp causes to increase pH solution Eo In the process of forming apatite, OH- as Ca2+, PO43- is consumed large quantities leading to reduce pH and rise Eo b The electrochemical impedance During 21 immesion days, the impedance of 316LSS increases, these values of doped HAp coated 316LSS changes, but they are much higher than 316LSS because of protection ability of coatings and tend to increase which demonstrates that the rate of the formation is higher than the rate of the dissolution of the coatings (Figure 3.20) Moreover, the variations of impedance modulus at 100 mHz frequency show that the values of impedance modulus of MgSrFNaHAp/316LSS and HApđt/316LSS material are higher than of NaHAp/316LSS and 316LSS which indicates that HAp doped with the present of some trate elements have the protection ability better than NaHAp coatings 22 12 316LSS NaHAp/316LSS 11 x : 100 mHz 18 Z'' (.cm ) day days days days 10 days 14 days 17 days 21 days 3 5 Z' (.cm ) HAp®t/316LSS x : 100 mHz IZI (k.cm ) 22 Z'' (.cm ) 20 18 16 14 12 10 day days days days 0 10 12 14 16 Z' (.cm ) 10 11 18 20 10 days 14 days 17 days 21 days 22 24 26 28 30 28 26 24 22 20 18 16 14 12 10 (d) (a) 10 12 14 Time (days) 20 10 12 14 16 18 20 22 Figure 3.20 Nyquist plots and the variation of impedance modulus at 100 mHz versus immersion time in SBF solution (b) 10 days 14 days 17 days 21 days (c) day days days days Z' (.cm ) a: 316LSS b: NaHAp/316LSS c: MgSrFNaHAp/316LSS d: HApdt/316LSS 12 Z' (.cm ) 24 10 2 28 26 12 0 14 10 days 14 days 17 days 21 days day days days days x : 100 mHz 16 Z'' (.cm ) Z'' (.cm ) MgSrFNaHAp/316LSS 20 x : 100 mHz 10 16 18 20 22 c The polarized Tafel curves The presence of trace elements in HAp structure leads to move the corrosion potential (Ecorr) toward the positive side and reduce the corrosive current density (icorr) in comparation with 316LSS (Figure 3.21 and Table 3.17) This indicates that the protection ability for the substrates of doped HAp coatings is better than that of NaHAp one Table 3.17 The values of the corrosion current density (icorr) and the corrosion potential (Ecorr) of meterials after immersion in SBF solution -3.5 (a): 316LSS (b): NaHAp/316LSS (c): MgSrFNaHAp/316LSS (d): HAp®t/316LSS -4.0 -5.0 lg(i), A/cm -4.5 -5.5 -6.0 Materials -6.5 -7.0 a b -7.5 -8.0 -8.5 -0.8 c d -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 E (V/SCE) Figure 3.21 The polarized Tafel curves of materials 316LSS NaHAp/316LSS MgSrFNaHAp/316LSS HApđt/316LSS Ecorr (V) -0.424 -0.354 -0.258 -0.213 icorr (µA/cm2) 2.773 0.842 0.355 0.193 d The SEM images Figure 3.22 presents SEM images of 316LSS, NaHAp/316LSS, MgSrFNaHAp/316LSS and HApđt/316LSS before and after immersion in SBF solution After immersion, the formation of new apatite crystals is observed on the surface of all materials Figure 3.22 SEM images of materials before (above) and after (under) 21 immersion days in SBF solution 3.2.1.2 Cytotoxicity ability test Results of the cytotoxicity ability test by Trypan Blue and the MTT method show that NaHAp or MgSrFNaHAp powder with different concentrations are safe for fibroblasts and lymphocyte cells 3.2.1.3 Antibacterial ability test The results of antibacterial ability test with three strains (P.aerugimosa, E coli and E.faecalis) show that: AgHAp and HApđt have good resistance to all 21 of them; CuHAp has a good effect on P aerugimosa; the HAp and ZnHAp have no effect on all strains; 3.2.2 In vivo test on the dog 3.2.2.1 Results of implantation at the thigh At the first days, the wound at implantation area has been edema but not bleeding After month, the skin was almost completely covered (Figure 3.23) Figure 3.24 The woud at implantation area Microscopic images at implantation area shows that all implanted animals have the same results The area of the direct contact with the material is forming a membrane link However, some lymphocyte cells appear on 316LSS and NaHAp/316LSS materials but in contrast, they are completely not observed on MgSrFHAp/316LSS material 3.2.2.2 Results of transplantation on the femur The wound has been edema but not bleeding at the first days and after month, the skin was almost completely covered at the location of transplantation Microscopic images at transplantation area shows that: - After week: all transplanted animals have the same results At the transplantation area, many osteoblasts cells are observed but acute inflammation cells still exist (Figure 3.24) Figure 3.24 Images of NaHAp/316LSS after week transplantation - After month: the acute inflammation cells have absented and the necrosis have not observed on all transplanted materials There are many osteoblasts cells on 316LSS and NaHAp/316LSS but still have the lymphocyte cells (Figure 3.25a) With MgSrFNaHAp/316LSS, the osteoblast concentrate on the location of the bone edge to form bone (Figure 3.25b) and form a membrane link attached on the surface of this material (Figure 3.25c) 22 Figure 3.25 Images of the osteoblast near the location of transplanted materials: 316LSS (a), MgSrFNaHAp/316LSS (b, c) after month - After months: There are many osteoblasts cells on 316LSS and NaHAp/316LSS but still have few the lymphocyte cells (Figure 3.26a) The tissues adhese on the surface of NaHAp/316LSS better than the 316LSS On the surface of MgSrFNaHAp/316LSS, the lymphocyte cells have not observed (Figure 3.26b) and a new bone layer is produced (Figure 3.26c) Figure 3.26 Images of the osteoblast near the location of transplanted materials: 316LSS (a), MgSrFNaHAp/316LSS (b, c) after months - After months: on all transplanted materials, there are not the lymphocyte cells (Figure 3.27a, b) On the surface of MgSrFNaHAp/316LSS, a thick new bone is formed which are rarely found out on 316LSS and NaHAp/316LSS (Figure 3.27c) Figure 3.27 Images of the osteoblast near the location of transplanted materials: 316LSS (a), MgSrFNaHAp/316LSS (b, c) after months CONCLUSIONS The optimal conditions is selected to synthesize the NaHAp coatings and NaHAp coatings doping magnesium, strontium and fluorine separately and simultaneously by cathodic scanning potential method: the scanning potential range of to -1.7 V/SCE (0 ÷ -1.8 V/SCE for FNaHAp); the reaction temperatures of 50 oC; the scanning time of 5; the scanning rate of mV/s in DNa2, DMg3, DSr3, DF3 DNaMgSrF, respectively The dope deposited HAp have crystals structure and single phase of HAp with the thickness about 7,6 ữ 8,1 àm The component wt% of the elements Na, Mg, 23 Sr or F in the NaHAp, MgNaHAp, SrNaHAp, FNaHAp coatings are 1.5; 0.2; 6.3x10-4 1.55 %, respectively and in the MgSrFNaHAp are 0.56 % Na; 0.14 % Mg; 0.03 % Sr and 1.5 % F The NaHAp coatings doping copper, siliver and zinc separately and simultaneously are synthesized successfully by ion exchange method and by the way: immersion the material of NaHAp/316LSS at room temperature in 4mL solutions containing separately or simultaneously: Cu(NO3)2 0.02 M, AgNO3 0.001 M and Zn(NO3)2 0.05 M about 30 minutes (10 minute for AgNaHAp coatings) The HAp coatings doping elements simultaneously: Mg, Sr, F, Na, Cu, Ag, Zn are synthesized successfully by the combination two methods: electrodeposition and ion exchange The HApđt obtained coatings have crystals structure with coral shape and single phase of HAp The component wt% of the elements Mg, Sr, F, Na, Cu, Ag and Zn in the coatings are 0,04; 0,03; 1,07; 0,15; 0,18; 0,39 1,06 %, respectively The presents of seven elements in the coatings lead to decrease the dissolution behaviors and increase the protect ability for the substrates The in vitro test in SBF solution by the methods of open circuit potential, electrochemical impedance measurements and the polarized Tafel curves show that the biological activity and the protect ability of these material follow the order: HApđt/316LSS > MgSrFNaHAp/316LSS > NaHAp/316LSS > 316LSS The cytotoxicity ability test by Trypan Blue and the MTT method show that NaHAp or MgSrFNaHAp powder with different concentrations are safe for fibroblasts cells The antibacterial ability test with three strains (P.aerugimosa, E coli and E.faecalis) show that: AgHAp and HApđt have good resistance to all of them; CuHAp has a good effect on P aerugimosa; the HAp and ZnHAp have no effect on all strains The in vivo test on dog’s body by implantation splints made from: 316LSS, NaHAp /316LSS and MgSrFNaHAp/316LSS at the thigh and on the femur with tested time from to months show that their biological compatibility follows the order: MgSrFNaHAp/316LSS > NaHAp /316LSS > 316LSS NEW CONTRIBUTIONS OF THESIS The HAp coatings doping elements simultaneously: Mg, Sr, F, Na, Cu, Ag, Zn are synthesized successfully on 316LSS substrates by the combination two methods: electrodeposition and ion exchange The presents of seven elements in the coatings lead increasing the abilities of the biological compatibility, the antibactery and the protection for the substrates and decreasing the dissolution behaviors in comparation with MgSrFNaHAp and NaHAp coatings 24 The in vivo tests on dog’s body with tested time from to months indicate that MgSrFNaHAp/316LSS with the presents of some trace elements (Mg, Sr and F) in the coatings lead the biological compatibility better than NaHAp/316LSS and uncoated 316LSS which is demonstrated by the forminations a thick new bone on the surface of MgSrFNaHAp/316LSS after months transplantation LIST OF PUBLICATIONS Pham Thi Nam, Nguyen Thi Thom, Nguyen Thu Phuong, Vo Thi Hanh, Nguyen Thi Thu Trang, Vu Thi Hai Van, Trinh Hoang Trung, Tran Dai Lam, Dinh Thi Mai Thanh Electrodeposition of substainable fluoridated Hydroxylapatite coatings on 316L stainless steel for application in bone implaint Green Processing and Synthesis, 5, 499 - 510, 2016 (ISI) Vo Thi Hanh, Pham Thi Nam, Nguyen Thi Thom, Do Thi Hai Dinh Thi Mai Thanh Electrodeposition of sodium doped hydroxyapatite coatings on 316L stailess steel Vietnam Journal of Chemistry, 55(3), 348 - 354, 2017 Vo Thi Hanh, Pham Thi Nam, Dinh Thi Mai Thanh Electrodeposition and characterization of strontium hydroxyapatite coatings on 316L stailess steel Vietnam Journal of Chemistry, 55(3e12), 346 - 350, 2017 Vo Thi Hanh, Pham Thi Nam and Dinh Thi Mai Thanh Synthesis ad characterization of copper doped hydroxyapatite on on 316L stailess steel HNUE Journal of Science 62(3), 51 - 59, 2017 Vo Thi Hanh, Le Thi Duyen, Do Thi Hai, Pham Thi Nam, Nguyen Thi Thom, Nguyen Thu Phuong, Dinh Thi Mai Thanh Electrodeposition and characterization of Mg2+, Sr2+, F-, Na+ co-doped hydroxyapatite coatings on 316L stailess steel Processdings of 6th Asian Symposium on Advanced Materials, 740 - 746, 2017 Vo Thi Hanh, Le Thi Duyen, Pham Thi Nam and Dinh Thi Mai Thanh Study on the electrochemical behavior of NaHAp/316L stainless steel materials in solution simulated body fluid Vietnam Journal of Chemistry 55(5E1,2), 114-119, 2017 Vo Thi Hanh, Pham Thi Nam, Nguyen Thu Phuong, Nguyen Thi Thom, Le Thi Phuong Thao, Dinh Thi Mai Thanh Electrodeposition and characterization of magnesium hydroxyapatite coatings on 316L stailess steel Vietnam Journal of Chemistry, 55(5), 657-662, 2017 Vo Thi Hanh, Pham Thi Nam, Nguyen Thu Phuong, Dinh Thi Mai Thanh Electrodeposition of co-doped hydroxyapatite coatings on 316L stailess steel Vietnam Journal of Science and technology, 56 (01), 94-101, 2018 Vo Thi Hanh, Le Thi Duyen, Pham Thi Nam and Dinh Thi Mai Thanh The influence of NaNO3 and H2O2 to electrodeposition process of sodium doped hydroxyapatite on 316L stailess steel substrates, HNUE Journal of Science accepted 6/2017 (DOI: 10.18173/2354-1059.2017-0011) 25 ... following: Synthesis and characterizations of trace elements codoped hydroxyapatite coatings on 316L stainless steel application in bone implaint” The objectives of thesis: - Trace elements (sodium,... Thi Mai Thanh Electrodeposition of substainable fluoridated Hydroxylapatite coatings on 316L stainless steel for application in bone implaint Green Processing and Synthesis, 5, 499 - 510, 2016... Investigating and selecting of optimal conditions for the synthesis of NaHAp coatings doping copper, siliver and zinc separately and simultaneously by ion exchange method - The HAp coatings doping elements