纯钽表面微弧氧化“类骨小梁”状多孔涂层的细胞相容性

目的 提高医用纯钽的生物活性,利用微弧氧化(MAO)技术在其表面制备出“类骨小梁”状分级多孔涂层,并对比该涂层与传统“火山坑”状MAO涂层以及机械抛光纯钽表面在表面粗糙度、亲水性以及细胞相容性方面的差异。方法 使用0.1 mol/L Na₂B₄O₇和0.05 mol/L Na₃PO₄电解液在纯钽表面分别制备出“类骨小梁”状及“火山坑”状多孔涂层(分别命名为B-MAO和P-MAO涂层)。采用扫描电镜、X射线衍射以及X射线光电子能谱对不同结构涂层进行形貌观察和相组成分析,使用十字划格法评价涂层结合强度,使用激光共聚焦显微镜测定涂层的表面粗糙度,使用接触角仪测量其亲水性,并将小鼠前成骨细胞(MC3T3-E1)接种于材料表面,对比不同形貌状态对细胞铺展、增殖以及成骨分化的影响。结果 MAO涂层物相主要为Ta₂O₅。B-MAO涂层由于内部孔隙度高,应力释放充分,涂层结合强度高,而P-MAO涂层则因具有分层现象和较大的残余应力,易从基体剥落。抛光...

Cytocompatibility of "Trabecular Bone-like" Porous Coating Prepared by Micro-arc Oxidation on Pure Tantalum

Tantalum is widely used as a biomedical implant material, but the bioinert of its surface may affect its bonding with bone tissue. To improve the bioactivity of tantalum, researchers usually treat it with surface modification, among which micro-arc oxidation (MAO) is an effective method. The MAO can prepare a ceramic coating with a porous structure and high coating adhesion. Meanwhile, it can easily incorporate some bioactive elements into the coating. In this work, a novel "trabecular bone-like" hierarchical porous coating was prepared on the tantalum surface by MAO to improve its bioactivity. The difference between this coating and the conventional "crater-like" MAO coating as well as the mechanically polished pure tantalum surface was compared in terms of surface roughness, hydrophilicity, cytocompatibility, etc. A tantalum rod (>99.9 wt%) with a diameter of 10 mm was cut into tantalum sheets with a thickness of 2 mm. All tantalum sheets were polished with emery paper and cleaned in an ultrasonic cleaner. The MAO was conducted with a bipolar pulse power supply with a constant current model. The frequency and duty circle were set at 600 Hz and 9%, respectively. The "trabecular bone-like" porous coatings (appointed as B-MAO coatings) were prepared on tantalum sheets with 0.1 M Na2B4O7 electrolyte with the work current set to 4 A. The "crater-like" porous coatings (appointed as P-MAO coatings) were prepared on tantalum sheets with 0.05 M Na3PO4 electrolyte with the work current set to 12 A. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to observe the coating''s morphology and to analyze the coating''s phase composition. The coating adhesion was evaluated through the cross-scratch method. Their surface roughness was analyzed with confocal laser scanning microscopy (CLSM). The surface hydrophilicity was measured with a contact angle (CA) meter. And mouse preosteoblasts (MC3T3-E1) were seeded on the surface of the materials to compare the effects of different surface morphology on cell spreading, proliferation, and osteogenic differentiation. The XRD results showed that the phase composition of the MAO coating was mainly Ta2O5. The B-MAO coating had a high internal porosity, which resulted in adequate stress relief and thus high bonding strength. In contrast, the P-MAO coating was easy to peel off from the substrate due to the delamination and the significant residual stress. The roughness (Ra) of the polished pure tantalum surface, the P-MAO and B-MAO coatings were 0.06, 1.50 and 1.58 mm. Their corresponding contact angles were 42.6°, 15.5° and 7.2° respectively. The initial cell adhesion results indicated that the number of cells on the MAO coatings was more than those on the polished pure tantalum surface, and the spreading ability of cells on the B-MAO coating was better than those on the P-MAO coating and polished tantalum surfaces. The results of CCK-8 test showed that the number of cells increased gradually with time. The proliferation ability of cells in the MAO group was better than those in the polishing group, and the B-MAO group showed the best proliferation ability. The B-MAO group was also higher than the P-MAO and polished tantalum groups in terms of ALP activity. In conclusion, the MAO coatings exhibit higher roughness as well as hydrophilicity than the polished pure tantalum surface, resulting in high cell adhesion and proliferation ability. Compared with the "crater-like" single porous coating, the "trabecular bone-like" hierarchical porous coating has great potential for applications in hard tissue replacement due to its higher bonding strength, superhydrophilicity, and higher cell spreading, proliferation and osteogenic differentiation ability.