Surface Characterization and Biocompatibility of Selenium‐Doped Hydroxyapatite Coating on Titanium Alloy

Selenium‐doped hydroxyapatite (HA) was biomimetically coated on Ti6Al4V plates with the aim of combining the anticancer and antibacterial properties of selenium with the biocompatibility and bioactivity of HA. For the coating process, the composition of 1.5 × SBF (solution with ion concentrations at 1.5 times that of simulated body fluid, SBF) was modified to include 0.15 mM selenate (SeO₄^2?) ion. The selenium‐doped HA coating was characterized by several methods, such as scanning electron microscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy. The cytotoxicity of selenium on osteoblast and osteosarcoma cells was determined. The coating was shown to inhibit the growth of Staphylococcus epidermidis.     

Biomimetic Hydroxyapatite Coating on Metal Implants

The combination of the high mechanical strength of metals with the osteoconductive properties of calcium phosphates make hydroxyapatite coatings on titanium implants widely used in orthopedic surgery. However, the most popular coating method, plasma spraying, exhibits some important drawbacks: the inability to cover porous implants and to incorporate biologically active agents, delamination, and particle release. The aim of this study was to elaborate a dense, strong, and thick calcium-phosphate coating on titanium and porous-tantalum implants using a two-step biomimetic procedure. In the first step, the implants were soaked in a solution that was 5 times more concentrated than regular simulated body fluid (SBF-A solution). A thin but uniform amorphous calcium-phosphate coating was deposited on the metal. Then, the implants were immersed in the SBF-B solution, which had a similar composition as the SBF-A solution, but with decreased contents of crystal growth inhibitors (i.e., Mg²⁺ and HCO₃⁻). This resulted in the fast precipitation of a 30 μm thick crystalline calcium-phosphate coating. The pH of the SBF-B solution and the thickness of the crystalline coating layer were studied as a function of time. The Fourier transform infrared spectra and X-ray diffraction patterns showed that this new coating closely resembles bone mineral. Our biomimetic coating should facilitate rapid bone formation around the implant, reducing therewith the patient's recovery time after surgery.     

Dip Coating of Calcium Hydroxyapatite on Ti-6Al-4V Substrates

Ti-6Al-4V alloy is the most commonly used metallic material in the manufacture of orthopedic implants. The main inorganic phase of human bone is calcium hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂, HA). To achieve better biocompatibility with bone, metal implants made of Ti-6Al-4V are often coated with bioceramics. Dip-coating techniques scarcely are used to apply HA onto metallic implants. New dipping-solution recipes to be used for HA coatings are described in this work. Scanning electron microscopy and X-ray diffractometry have been used for sample characterization.     

碱处理法制备钛合金表面羟基磷灰石涂层

采用碱处理法制备钛基羟基磷灰石涂层,考察了碱液处理中有关钛合金表面活化参数对其诱导羟基磷灰石沉积速度的影响,采用X射线衍射和扫描电镜对样品的化学组成、结构和性能进行了表征,确定了钛合金表面活化处理的最优参数.结果表明,钛基体经10 mol/L氢氧化钠,饱和硝酸钙预钙化处理,模拟体液中培养后,羟基磷灰石沉积速度快,14 d就可形成致密﹑均匀﹑裂纹少的涂层;碱液处理后饱和硝酸钙溶液预钙化可得到片状的羟基磷灰石生物矿化层;且钛基体在600 ℃的热处理是HAP涂层沉积的重要条件之一.与相关研究相比较,该方法的优点在于可在形状复杂的植入体上形成均匀的涂层,工艺简单,并且涂层与基体结合牢固.     

Preparation and Characterization of Lanthanum-Incorporated Hydroxyapatite Coatings on Titanium Substrates

Titanium (Ti) has been widely used in clinical applications for its excellent biocompatibility and mechanical properties. However, the bioinertness of the surface of Ti has motivated researchers to improve the physicochemical and biological properties of the implants through various surface modifications, such as coatings. For this purpose, we prepared a novel bioactive material, a lanthanum-incorporated hydroxyapatite (La-HA) coating, using a dip-coating technique with a La-HA sol along with post-heat treatment. The XRD, FTIR and EDX results presented in this paper confirmed that lanthanum was successfully incorporated into the structure of HA. The La-HA coating was composed of rod-like particles which densely compacted together without microcracks. The results of the interfacial shear strength test indicated that the incorporation of lanthanum increased the bonding strength of the HA coating. The mass loss ratios under acidic conditions (pH = 5.5) suggested that the La-HA coatings have better acid resistance. The cytocompatibility of the La-HA coating was also revealed by the relative activity of alkaline phosphatase, cellular morphology and cell proliferation assay in vitro. The present study suggested that La-HA coated on Ti has promising potential for applications in the development of a new type of bioactive coating for metal implants.     

Self-Lubrication of Chlorine-Implanted Titanium Nitride Coating

Chlorine implantation into TiN coatings decreases the wear loss and the friction coefficient. Even by low-dose chlorine implantation, the wear volume is decreased by three orders of magnitude or more, and the friction coefficient becomes <0.1. This self-lubrication mechanism is related to the presence and mobility of implanted chlorine atoms inside the columnar TiN microstructure. According to observations of chlorine-implanted TiN coatings using high-resolution transmission electron microscopy, the chlorine atoms are present in the damaged region, where TiN is composed of nanosized grains. From these data, a self-lubrication mechanism is proposed with chlorine catalyzing the oxidation of titanium and leading to the formation of some tribological reaction product.     

Composition and Crystallization of Hydroxyapatite Coating Layer Formed by Electron Beam Deposition

To improve the biocompatibility of Ti-based metal implants, a hydroxyapatite (HA) coating layer was formed on the surface by electron-beam deposition. The dissolution rate of the coating layer was strongly dependent on the layer's calcium/phosphorus (Ca/P) ratio. Layers with a Ca/P ratio close to that of crystalline HA (Ca/P = 1.67) showed good stability in a physiologic saline solution. When the layer was crystallized by heat treatment in air at temperatures between 400° and 500°C, the stability was enhanced further while maintaining good interfacial bonding strength with the substrate. Preliminary in vivo tests on rabbits indicated that heat treatment and the resultant enhancement in stability are beneficial for bone attachment to the implants.     

溶胶凝胶法制备钛基羟基磷灰石涂层的研究

混合硝酸钙乙醇溶液和磷酸三甲酯水溶液作为羟基磷灰石(HA)前驱体,利用旋转涂膜技术在钛片表面制备羟基磷灰石涂层.研究了溶胶陈化时间和凝胶热处理温度对涂膜的影响,同时对涂层的生物活性进行了研究.样品利用X射线衍射仪(XRD)和扫描电子显微镜(ESEM)进行表征.结果表明:利用经过24 h陈化的溶胶涂膜的样品在500℃热处...     

Glass-Ceramic Protective Coating for Titanium Alloys

A glass-ceramic coating that protects a titanium alloy against oxidation during heat treatment has been successfully developed. In the present study, the conditions for preparing this glass-ceramic coating were investigated. In addition, the prepared coating was characterized by X-ray diffractometry, energy-dispersive spectroscopy analysis, and oxygen weight-gain testing. The results showed that the glass-ceramic coating has excellent oxygen-proof properties to protect the titanium alloy from oxidation by the atmosphere at high temperature (900°C).     

羟基磷灰石涂层的制备

本文以五氧化二磷、无水乙醇、硝酸钙为原料,通过溶胶-凝胶法制备羟基磷石灰涂层。选用2mm/s的速度浸渍提拉载玻片,在载玻片上进行涂膜,经60℃干燥后在650℃烧结保温3h,可在载玻片上得到羟基磷灰石涂层。研究结果表明:制备溶胶合适的配比为Ca(NO3)22·4H2O:P2O5(摩尔比)=10:3,即Ca/P原子比=5:3(约等于1.67)。     

在改性模拟体液中电沉积羟基磷灰石涂层

Hydroxyapatite coatings were directly prepared on anodized titanium by electro-deposition method in a modified simulated body fluid. The configuration, structure and bioactivity of the coating were investigated with scanning electron microscopy (SEM), X-ray diffraction analyzer (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. The results demonstrated that pure and homogeneous hydroxyapatite coating can be obtained without any post-treatment. The prepared coating showed good bioactivity in simulated body fluid (SBF). The time required for a fully covered dense hydroxyapatite coatings was 4 days immersion in SBF.     

羟基磷灰石涂层的生物仿生法研究进展

羟基磷灰石的生物复合涂层具有很高的外科应用价值.制备羟基磷灰石复合材料的方法有很多种,其中仿生法模仿了自然界生理磷灰石的矿化机制,在类似于人体组织内环境条件的水溶液中自然沉积出磷灰石层.仿生法具有许多其它方法无可比拟的优越性.本文对近年来文献报道中出现的生物仿生法进行了综述,阐述了各种仿生法中包括对基体进行预处理使其表面官能团化,再将基体在模拟体液中浸泡从而使磷灰石自然沉积的模拟生物矿化的4个阶段的工艺过程及其仿生机理.     

等离子喷涂羟基磷灰石涂层

羟基磷灰石由于具有优良的生物性能，被广泛应用于生物材料领域，而等离子喷涂制备羟基磷灰石涂层是应用最为广泛的制备方法之一。在综合国内外献的基础上，本从羟基磷灰石的本征性能、喷涂工艺的影响、结合强度和梯度涂层等方面进行综述。     

羟基磷灰石生物陶瓷涂层制备方法评述

根据医用生物陶瓷羟基为磷灰石及医用金属材料的生物，力学特性，本文认为在金属基体表面涂覆羟基磷灰石是综合金属材料及生物陶瓷材料各自优越性阳有希望的途径这一。评述了羟基磷灰石涂层的制备方法，论证了较为优化的涂层结构。     

Deposition of Nanostructured Fluorine‐Doped Hydroxyapatite Coating from Aqueous Dispersion by Suspension Plasma Spray

In this study, we prepared an aqueous dispersion of fluorine‐doped hydroxyapatite (FHA) nanoparticles by a wet chemical method. For the first time, the as‐prepared aqueous dispersion of FHA nanoparticles was directly used as suspension for depositing nanostructured FHA coating on stainless steel substrate by suspension plasma spray (SPS) method. Field‐emission scanning electron microscopy images confirm that the coating was nanostructured. X‐ray Diffraction pattern, Fourier‐transform infrared spectroscopy, and Raman spectra show that the as‐sprayed coating was FHA phases. The experimental result confirmed that OH^? and F^? ions have been well kept in FHA crystal lattice and structural integrity has been maintained during SPS process by using an aqueous dispersion of FHA nanoparticles. The potentiodynamic polarization and electrochemical impedance spectroscopy results prove that the nanostructured FHA coating can greatly enhance the anticorrosion performance of stainless steel in phosphate‐buffered saline solution.     

Preliminary Experiments of In Situ Atomic Force Microscopy Observation of Hydroxyapatite Formation on Bioactive Glass Surface

This paper demonstrates the use of atomic force microscopy (AFM) to image the bioactivity of phosphate glasses that are well-known to react rapidly in simulated body fluid. The present study demonstrates that the hydroxyapatite (HAP) crystalline layer found via AFM in the examined samples coincides with that identified using scanning electron microscopy. Moreover, the effect of a notorious bacteriostatic cation—tetravalent cerium, Ce(IV)—on the kinetics of the HAP layer is investigated in CeO₂-doped bioactive glasses.     

电泳沉积磷灰石生物陶瓷涂层的研究进展

羟基磷灰石(HA)生物涂层材料是最有发展前途的生物硬组织替代材料之一.电泳沉积具有装置简单,操作方便,非线性,沉积温度低等特点,可以解决传统HA生物陶瓷涂层制备工艺上的各种不足.文中探讨了电泳沉积的各种工艺影响因素,综合介绍了国内外有关电泳沉积HA复合(梯度)生物涂层和电泳沉积与其它方法复合制备HA生物涂层的研究报道,进而提出了相应的设想和展望.     

羟基磷灰石复合涂层制备的研究进展

将羟基磷灰石复合涂层按照特征分为三类,即单层复合涂层、双层复合涂层和梯度复合涂层。概述了这三类羟基磷灰石复合涂层的特点,并简要介绍这三类羟基磷灰石复合涂层的制备方法和研究进展,对开发出反应步骤更为简单,反应条件更为湿和,生物相容性更好的硬组织置换材料的研究前景进行了展望。     

通过仿生法在纯镁表面制备羟基磷灰石涂层的研究

在纯镁表面自组装单分子层,用CaCl2和K2HPO4溶液对其进行预钙化处理,将处理过的纯镁试样浸泡于钙磷饱和溶液,仿生沉积得到羟基磷灰石涂层。利用X射线衍射和扫描电子显微镜对形成的涂层进行表征。试验结果表明,6天后即在镁基体表面得到了均匀致密、以羟基磷灰石（HA）为主晶相的羽毛状涂层。     

金属基生物活性羟基磷灰石涂层材料的研究进展

羟基磷灰石(HA)是人体和动物的骨骼和牙齿的主要无机成分,人工合成的羟基磷灰石具有良好的生物相容性和生物活性,但质脆;医用金属材料具有较好的强度、韧性和优良的加工性能,但是生物相容性差。金属基生物活性HA涂层材料兼备金属材料优良的力学性能和生物陶瓷材料的生物相容性,成为近年来发展最为迅速的一种生物材料。本文简要评述了国内外金属基HA涂层材料的研究进展状况,主要介绍了制备金属基HA涂层材料的各种物理化学方法,提出了一些存在的问题和解决方法,展望了制备HA复合涂层的发展前景。