An oxide ceramic coating can be formed on the surface of magnesium alloy by micro-arc oxidation so that the corrosion resistance of the magnesium alloy can be enhanced. In this paper, a general overview of the surface treatment of micro-arc oxidation on the surface of magnesium alloy is presented, the related research on the treatment of several kinds of magnesium alloys is introduced in detail, and a brief introduction of biological activity of magnesium alloy due to micro-arc oxidation is given. Finally, the technical advantages and existing problems are summarized.
ObjectiveTo evaluate the effect of a novel micro-arc oxidation (MAO) coated magnesium-zinc-calcium (Mg-Zn-Ca) alloy scaffold/autologous bone particles to repair critical size bone defect (CSD) in rabbit and explore the novel scaffold in vivo corrosion resistance and biocompatibility.MethodsSeventy-two New Zealand white rabbits were randomly divided into 3 groups (n=24), group A was uncoated Mg-Zn-Ca alloy scaffold group, group B was 10 μm MAO coated Mg-Zn-Ca alloy scaffold group, and group C was control group with only autologous bone graft. The animals were operated to obtain bilateral ulnar CSD (15 mm in length) models. The bone fragment was removed and minced into small particles and were filled into the scaffolds of groups A and B. Then, the scaffolds or autologous bone particles were replanted into the defects. The animals were sacrificed at 2, 4, 8, and 12 weeks after surgery (6 rabbits each group). The local subcutaneous pneumatosis was observed and recorded. The ulna defect healing was evaluated by X-ray image and Van Gieson staining. The X-ray images were assessed and scored by Lane-Sandhu criteria. The percentage of the lost volume of the scaffold (ΔV) and corrosion rate (CR) were calculated by the Micro-CT. The Mg2+ and Ca2+ concentrations were monitored during experiment and the rabbit liver, brain, kidney, and spleen were obtained to process HE staining at 12 weeks after surgery.ResultsThe local subcutaneous pneumatosis in group B was less than that in group A at 2, 4, and 8 weeks after surgery, showing significant differences between 2 groups at 2 and 4 weeks after surgery (P<0.05); and the local subcutaneous pneumatosis was significantly higher in group B than that in group A at 12 weeks after surgery (P<0.05). The X-ray result showed that the score of group C was significantly higher than those of groups A and B at 4 and 8 weeks after surgery (P<0.05), and the score of group B was significantly higher than that of group A at 8 weeks (P<0.05). At 12 weeks after surgery, the scores of groups B and C were significantly higher than that of group A (P<0.05). Meanwhile, the renew bone moulding of group B was better than that in group A at 12 weeks after surgery. Micro-CT showed that ΔV and CR in group B were significantly lower than those in group A (P<0.05). Van Gieson staining showed that group B had better biocompatibility and osteanagenesis than group A. The Mg2+ and Ca2+ concentrations in serum showed no significant difference between groups during experiments (P>0.05). And there was no obvious pathological changes in the liver, brain, kidney, and spleen of the 3 groups with HE staining at 12 weeks.ConclusionThe MAO coated Mg-Zn-Ca alloy scaffold/autologous bone particles could be used to repair CSD effectively. At the same time, 10 μm MAO coating can effectively improve the osteanagenesis, corrosion resistance, and biocompatibility of Mg-Zn-Ca alloy scaffold.
【摘要】 目的 探討微弧氧化（microarc oxidation，MAO）結合應用于純鈦種植體表面處理的可行性。 方法 根據對純鈦鈦片處理的不同將實驗分為對照組（A組，不作處理）、MAO組（B組，純鈦片上進行MAO處理）及MAO加Ⅰ型膠原組（C組，純鈦片上MAO處理后吸附Ⅰ型膠原）。將成骨細胞培養于各組鈦片上，通過掃描電鏡、MTT法檢測不同時間點各組鈦片表面的細胞生長及增殖情況，并檢測堿性磷酸酶（alkaline phosphatase，ALP）活性。 結果 掃描電鏡顯示成骨細胞在C組鈦片上細胞黏附情況優于A、B組；MTT法及ALP活性檢測示培養3、6 d，成骨細胞在C組鈦片上的增殖及ALP活性與A、B組比較差異均有統計學意義（Plt;0.05）。 結論 MAO結合Ⅰ型膠原處理的鈦片可更有效提高成骨細胞表面附著、增殖，且具有較高的ALP活性。【Abstract】 Objective To study the feasibility of applying microarc oxidation (MAO) with collagen Ⅰ in surface modification of pure titanium. Methods According to different processing methods, the pure titanium was divided into three groups: the control group (without surface modification, group A), MAO group (with microarc oxidation applied in pure titanium surface modification, group B), MAO+Ⅰ group (with microarc oxidation and collagen Ⅰ applied in pure titanium treatment, group C). Osteoblasts were cultured on the surface of titanium in each group, and the cell proliferation in each group was detected at different time points by scanning electron microscopy and MTT method. Moreover, the activity of alkaline phosphatase (ALP) was also detected. Results Scanning electron microscopy showed that adhesion of osteoblasts for group C was better than group A and group B. MTT method and ALP activity detection indicated that there was a significant difference between group C and group A, B in cell proliferation and ALP activity on the third and sixth day of cultivation (Plt;0.05). Conclusion MAO with collagen Ⅰ applied in surface modification of pure titanium may increase osteoblast attachment, and promote its proliferation and ALP activity.
Objective To research in vitro biocompatibility of silicon containing micro-arc oxidation (MAO) coated magnesium alloy ZK60 with osteoblasts. Methods The surface microstructure of silicon containing MAO coated magnesium alloy ZK60 was observed by a scanning electron microscopy (SEM), and chemical composition of the coating surface was determined by energy dispersive spectrum analysis. The experiments were divided into 4 groups: silicon containing MAO coated magnesium alloy ZK60 group (group A), uncoated magnesium alloy ZK60 group (group B), titanium alloy group (group C), and negative control group (group D). Extracts were prepared respectively with the surface area to extraction medium ratio (1.25 cm2/ mL) according to ISO 10993-12 standard in groups A, B, and C, and were used to culture osteoblasts MC3T3-E1. The α-MEM medium supplemented with 10% fetal bovine serum was used as negative control in group D. The cell morphology was observed by inverted phase contrast microscopy. MTT assay was used to determine the cell viability. The activity of alkaline phosphatase (ALP) was detected. Cell attachment morphology on the surface of different samples was observed by SEM. The capability of protein adsorption of the coating surface was assayed, then DAPI and calcein-AM/ethidium homodimer 1 (calcein-AM/EthD-1) staining were carried out to observe cell adhesion and growth status. Results The surface characterization showed a rough and porous layer with major composition of Mg, O, and Si on the surface of silicon containing MAO coated magnesium alloy ZK60 by SEM. After cultured with the extract, cells grew well and presented good shape in all groups by inverted phase contrast microscopy, group A was even better than the other groups. At 5 days, MTT assay showed that group A presented a higher cell proliferation than the other groups (P lt; 0.05). Osteoblasts in groups A and C presented a better cell extension than group B under SEM, and group A exhibited better cell adhesion and affinity. Protein adsorption in group A [ (152.7 ± 6.3) μg/mL] was significantly higher than that of group B [(96.3 ± 3.9) μg/mL] and group C [ (96.1 ± 8.7) μg/mL] (P lt; 0.05). At each time point, the adherent cells on the sample surface of group A were significantly more than those of groups B and C (P lt; 0.05). The calcein-AM/EthD-1 staining showed that groups A and C presented better cell adhesion and growth status than group B. The ALP activities in groups A and B were 15.55 ± 0.29 and 13.75 ± 0.44 respectively, which were significantly higher than those in group C (10.43 ± 0.79) and group D (10.73 ± 0.47) (P lt; 0.05), and group A was significantly higher than group B (P lt; 0.05). Conclusion The silicon containing MAO coated magnesium alloy ZK60 has obvious promoting effects on the proliferation, adhesion, and differentiation of osteoblasts, showing a good biocompatibility, so it might be an ideal surface modification method on magnesium alloys.