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Objective@# To investigate the effect of cobalt (Co) and calcium-phosphate (Ca/P) doped coating on titanium surfaces and their angiogenic effect.@*Methods @# Microarc oxidation (MAO) was used to prepare Co-Ca/P-doped and Co-doped coatings. Titanium (Ti) sheet without MAO treatment was used as control. Scanning electron microscopy (SEM) was used to observe the surface micromorphology of the coatings. Energy dispersive spectrometry (EDS) was also applied to detect the doped chemicals and their contents. Standard soaking solutions of these coatings were prepared using an endothelial cell medium (ECM) solution for subsequent angiogenesis experiments. Human umbilical vein endothelial cells (HUVECs) were cultured on Matrigel with ECM soaking solutions for 4 h and 8 h. The microvessels were observed under a microscope, and the number of microtubules and their interconnecting nodes were analyzed with Image J software. @*Results@# Co doped and Co-Ca/P-doped coatings were successfully prepared by MAO, which was demonstrated by both SEM observation and EDS analysis. SEM observation showed that irregular crystals of the above chemicals were present on both Co and Co-Ca/P-doped coatings, commonly with a diameter <2 μm. However, more crystals were observed on the Co-Ca/P coatings than on the Co coating, and the distribution of the crystals was more homogenous on the Co-Ca/P coatings. However, only polishing scratches were observed on the Ti sample surface. EDS analysis indicated that in contrast to only Co in the Co coating, Co, Ca and P were doped within the Co-Ca/P coating, and none of the three elements were observed on the Ti plate surface. The number of vascular rings and nodes formed by HUVECs in the extract of the Co-Ca/P group was significantly higher than that of the Co group (P<0.05), and the angiogenic effect of these two components was significantly better than that of the Ti group (P<0.05). @*Conclusion@#The Co-Ca/P coating exhibits good angiogenic properties in vitro and is valuable for the development of new titanium implants with high surface bioactivity.
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BACKGROUND: Electrochemical method based nanoscale hydroxyapatite coating has slow degradation speed (8-12 weeks). Micro-arc oxidation based method could form homogeneous coating on complex surfaces, and this coating promotes cell adhesion and ingrowth in bone tissues. OBJECTIVE: To explore the effect of micro-arc oxidation hydroxyapatite coating titanium alloy on osteoblast proliferation and osteogenic differentiation ability. METHODS: Hydroxyapatite coating titanium alloy materials were prepared by electrochemical method and micro-arc oxidation method. The contact angles of the two materials were detected. Osteoblasts (hFOB1.19) were incubated on the hydroxyapatite coating titanium alloy materials for 48 hours. The morphological changes of osteoblasts on the materials were observed under scanning electron microscope. The cell proliferation was detected by MTT method at 1, 12, 24, 48 and 72 hours. The cell count and alkaline phosphatase activity were detected at 1, 3 and 5 days of culture. At 5 days, the expression levels of bone morphogenetic proteins 2 and 4 were detected by western blot assay. RESULTS AND CONCLUSION: (1) The contact angle in the micro-arc oxidation group was smaller than that in the electrochemical group [(66.5±2.2)°, (52.8±2.1)°, P=0.001 5)]. (2) Scanning electron microscope revealed that the osteoblasts in the electrochemical group had an irregular and shrunken shape, and adhered loosely to the material surface. The osteoblasts in the micro-arc oxidation had a fully outstretched and flat shape, and adhered tightly to the material surface. (3) From 12 to 72 hours, the cell proliferation in the micro-arc oxidation group was faster than that in the electrochemical group (P < 0.05). At 3 and 5 days after culture, the cell proliferation in the micro-arc oxidation group was faster than that in the electrochemical group (P < 0.05). (4) At 1, 3 and 5 days, the alkaline phosphatase activity of osteoblasts in the micro-arc oxidation group was higher than that in the electrochemical group (P < 0.05). (5) The expression levels of bone morphogenetic proteins 2 and 4 were significantly up-regulated in the micro-arc oxidation group compared with the electrochemical group (P < 0.05). (6) These results indicate that micro-arc oxidation hydroxyapatite coated titanium alloy increases osteoblast proliferation and osteogenic differentiation ability.
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Objective To evaluate the implant-bone interfaces on implants with active Zn coating in a rabbit model.Methods Pure titanium cylinder implants,fabricated by machining,were prepared by surface microarc oxidation (MAO).The MAO-Zn/Ca/P coated (experimental group) and the MAO-Ca/P coated (control group)implants were randomly placed in the rabbit mandible.The samples were harvested at 4 and 12 weeks postoperatively,histological analysis on the implant-bone interfaces of the two implants was performed,and the bone coverage was compared.Results The coatings of MAO presented micro-porous structure with dense and uniform features,in which size of micro-porous increased with zinc element.The histological examination of implant-bone contact interfaces showed that the bone tissues attached on the coatings increased with time.Further,the adhered bone tissue in the experimental group was thicker and denser and had a larger amount compared to that in the control group at 4 and 12 weeks postoperatively.The bone coverage in the experimental group (70.8％±13.6％) at 12 weeks postoperatively was significantly higher than that in the control group (55.9％±13.8％) (P＜0.05).The results of bone interface element showed that the apatite layer was precipitated at 12 weeks.Conclusion The addition of active zinc element can improve the biological activity of the coating,enhance the osteogenesis ability of the coating,and accelerate the osseointegration of implant-bone interfaces.
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In our previous studies,a novel cortex-like TiO2 coating was prepared on Ti surface through micro-arc oxidation (MAO) by using sodium tetraborate as electrolyte,and the effects of the coating on cell attachment were testified.This study aimed to investigate the effects of this cortex-like MAO coating on osseointegration.A sand-blasting and acid-etching (SLA) coating that has been widely used in clinical practice served as control.Topographical and chemical characterizations were conducted by scanning electron microscopy,energy dispersive X-ray spectrometer,X-ray diffraction,contact angle meter,and step profiler.Results showed that the cortex-like coating had microslots and nanopores and it was superhydrophilic,whereas the SLA surface was hydrophobic.The roughness of MAO was similar to that of SLA.The MAO and SLA implants were implanted into the femoral condyles of New Zealand rabbits to evaluate their in-vivo performance through micro-CT,histological analysis,and fluorescent labeling at the bone-implant interface four weeks after surgery.The micro-CT showed that the bone volume ratio and mean trabecular thickness were similar between MAO and SLA groups four weeks after implantation.Histological analysis and fluorescent labeling showed no significant differences in the bone-implant contact between the MAO and SLA surfaces.It was suggested that with micro/nanostructure and superhydrophilicity,the cortex-like MAO coating causes excellent osseointegration,holding a promise of an application to implant modification.
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Objective:To study the cytocompatibility of Zr-Cu-Al-Ag alloy coated by micro-arc oxidation.Methods:Components of Zr-Cu-Al-Ag alloy coated by micro-arc oxidation in three different voltages of 300 V,350 V and 400 V,Zr-Cu-Al-Ag alloy as cast condition and TI6Al4V alloy were made for the test.The water extracted from the components were obtained according to national standard.The L929 cells were cultivated in vitro in the extracts of these components separately.The L929 cells,cultured in Dulbecco's modified Eagle medium supplemented with 10 ％ fetal calf serum,served as the negative control group.And cells,cultured in Dulbecco's modified Eagle medium supplemented with 10 ％ fetal calf serum and 64 g/L phenol,served as the positive control group.The cytocompatibility of these components were evaluated by MTT colorimetric.Results:The cytotoxicity of Zr-Cu-Al-Ag alloy coated by micro-arc oxidation is 0 grade.Microscopy showed that the morphology of L929 cells,cultured in the extracts of Zr-Cu-Al-Ag alloy coated by micro-arc oxidation were normal.There were no significant differences between micro-arc oxidationt and negative control groups.The cell multiplication curves of micro-arc oxidation and negative control groups were nearly overlapping and in the linearity increasing trend.The OD in micro-arc oxidation groups had no significant differences with negative control group (P＞0.05),but were higher than that of Zr-Cu-Al-Ag alloy as cast condition,TI6Al4V alloy and positive control groups (P＜0.05).Conclusions:The cytocompatibility of Zr-Cu-Al-Ag alloy has been improved by micro-arc oxidation technique.
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Magnesium and its alloys have recently been used in the development of lightweight, biodegradable implant materials. However, the corrosion properties of magnesium limit its clinical application. The purpose of this study was to comprehensively evaluate the degradation behavior and biomechanical properties of magnesium materials treated with micro-arc oxidation (MAO), which is a new promising surface treatment for developing corrosion resistance in magnesium, and to provide a theoretical basis for its further optimization and clinical application. The degradation behavior of MAO-treated magnesium was studied systematically by immersion and electrochemical tests, and its biomechanical performance when exposed to simulated body fluids was evaluated by tensile tests. In addition, the cell toxicity of MAO-treated magnesium samples during the corrosion process was evaluated, and its biocompatibility was investigated under in vivo conditions. The results of this study showed that the oxide coating layers could elevate the corrosion potential of magnesium and reduce its degradation rate. In addition, the MAO-coated sample showed no cytotoxicity and more new bone was formed around it during in vivo degradation. MAO treatment could effectively enhance the corrosion resistance of the magnesium specimen and help to keep its original mechanical properties. The MAO-coated magnesium material had good cytocompatibility and biocompatibility. This technique has an advantage for developing novel implant materials and may potentially be used for future clinical applications.
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Adult , Female , Humans , Middle Aged , Cognition Disorders/psychology , Hospitals , Personnel, Hospital/psychology , Stress, Psychological/psychology , Cognition Disorders/epidemiology , Finland/epidemiology , Surveys and QuestionnairesABSTRACT
Objective:To investigate the effects of titanium surface modified by micro-arc oxidation (MAO)on the collagen secre-tion and the expression of osteogenesis-related genes of MC3T3-E1 cells.Methods:Pure titanium discs were divided into two groups:Titanium with modified surface by MAO(MAO group)and titanium with polished surface(PT group).Tissue culture polysty-rene plates (TC)were used as controls.Surface morphology of the samples was examined by field-emission scanning electron micros-copy(FESEM).Surface roughness of samples was measured by surface roughness meter.MC3T3-E1 cells were cultured on the sur-face of the samples and the collagen secretion on the samples was measured by sirius red-based colorimetric microassay after 12 days of culture.On day 16 of culture,the expression of osteogenesis-related genes was examined by RT-PCR.Results:A porous oxide layer was observed on the surface of MAO treated samples and the surface roughness was more than that of PT group(P<0.01 ). Cells in MAO group showed higher collagen secretion than in PT or TC groups(P<0.05).MAO treated surface induced higher OSX, COL-Iα1 and OPN expression than PT.Conclusion:MAO treated titanium surface may induce more collagen secretion of MC3T3-E1 cells than PT.
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10.3969/j.issn.2095-4344.2013.25.002
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Objective; To evaluate the influence of electrolyte's concentration at micro-arc oxide treatment on the bonding strength of titanium to porcelain. Methods; CP titanium specimens with size of 25 mm ×3 mm ×0. 5 mm were treated with micro-arc oxidation (MAO) in Na_2SiO_3 solution of three different concentrations. After ultra-low-fusing porcelain was applied, a three-point-flexure-test was used to evaluate the bonding strength of titanium to porcelain. The surface of the specimens was observed by SEM and EDS, as well as the interface between titanium and porcelain. Results; The bonding strength values between titanium treated with MAO and porcelain was significantly higher then the control groups, Croup 20 g/L has the highest bonding strength values. SEM/EDS suggested that a porous thin layer of oxide which contains Si element is created by MAO, and higher concentration of Na_2SiO_3 leads to more Si element in oxide. Conclusion; MAO treating can improve the bonding strength between titanium and ceramic. Electrolyte's concentration has an effect on the bond strength between titanium and porcelain.
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Objective:To study the effects of duty cycle and frequency of microarc oxidation(MAO) on the titanium ceramic bonding strength.Methods:Titanium samples were treated with MAO in a Na2SiO3 electrolytic solution with voltage 300 V?3 min. According to the different duty cycle and frequency,experimental groups were named as:group Ⅰ(0.2, 500 Hz); group Ⅱ(0.2, 1 000 Hz); group Ⅲ(0.04,1 000 Hz); group Ⅳ(0.04,500 Hz) and group Ⅴ(0.12,750 Hz). The non-MAO samples were used as a control group.The surface of the samples was observed by scanning electron microscope (SEM).The samples were bonded to porcelain,and the bonding strength was measured by a three point bending test according to ISO 9693.Results:The surfaces of 1 000 Hz test pieces were smaller holes,more holes in the number and thicker layer than that of 500 Hz. When measured the bonding strength(MPa) of the samples, group Ⅳ was higher than group Ⅲ(P