纯钛阳极氧化及表面薄层羟基磷灰石形成技术的研究 Ⅱ．电解质及电压对氧化膜性能的影响

目的：了解电解质和电压因素对氧化膜成分、形态和稳定性能的影响。方法：将纯钛片分别在六种不同浓度电解质中（β－磷酸甘油钠：醋酸钙＝0.01M:0.15M,0.02M:0.20M,0.03M:0.25M,0.04M:0.25M,0.05M:0.25M,0.06M:0.30M)和4种不同电压条件下（200V,250V,300V,350V）进行阳极氧化,观察表面氧化膜性能的改变。结果：随着电解质和电压的增加,钛表面氧化膜突起高度增加,孔隙,边缘逐渐不平滑,形状逐渐不规则。能谱分析表明,在形成近HA化学当量的6组电解质中,Ca/Ti比随电解质浓度的增加而增加。结论：根据HA的析出量和氧化膜的稳定性,确定β－磷酸甘油钠：醋酸钙=0.04M:0.25M为较佳电解质浓度比（Ca/Ti比为3.6);根据Ca/P比值,确定300V为最佳电解条件（Ca/P比为1．8）。     

阳极氧化促进钛表面生物矿化的研究

目的：用阳极氧化法在纯钛表面制备纳米二氧化钛管（TiO2nanotube）以及TiO2纳米管诱导羟基磷灰石（HA）沉积的能力。方法：用扫描电子显微镜（SEM）观察钛片在不同氧化时间和电压下,在含0．1mol／LNaH2PO4和0．1mol／LNH4F的电解液中阳极氧化后的表面形貌。经阳极氧化后的样本在SBF溶液中进行体外矿化处理,矿化后的试样用SEM、X射线衍射分析仪（XRD）观察分析羟基磷灰石（HA）的形貌和晶形。结果：在20V电压下,氧化2h,钛表面形成孔径均一、排列规整的纳米二氧化钛管;在20V电压下氧化2h的试样（实验组）与末经阳极氧化的试样（对照组）在仿生体液中浸泡7d后,实验组表面沉积的HA晶体更多。结论：阳极氧化时间、电压对钛表面的TiO2纳米管形貌及结构产生影响,TiO2纳米管可以加速诱导HA在其表面沉积。     

纯钛阳极氧化及表面薄层羟基磷灰石形成技术的研究Ⅲ.蒸汽温度及Ca2+浓度对氧化膜表面析出晶体性能的影响

目的：了解蒸汽温度及Ca^2 浓度对氧化膜表面析出晶体性能的影响。方法：将钛片分别在六种不同Ca^2 浓度的电解质溶液中进行电解（β-磷酸甘油钠：醋酸钙=0.04M:0.15M,0.04M:0.20M,0.04M;0.25M,0.04M:0.30M,0.04M:0.35M,0.04M:0.40M)和在三种不同蒸汽温度下进行水热处理（200℃，250℃，300℃）。结果：随着水热温度的增高，钛片表面晶体开始析出并增多，在200℃水热处理时，钛片表面几乎无晶体析出，300℃为较理想的水热温度的增高，钛片表面晶体开始析出并增多，在200℃水热处理时，钛片表面几乎无晶体析出，300℃为较理想的水热处理温度，随着Ca^2 浓度的增加，钛片表面晶粒逐渐变细，增多，形状逐渐规则，Ca/P比则从1-3不等，结论：蒸汽温度以及Ca^2 浓度对于氧化膜表面结晶物和HA的析出有重要的影响。HA在高温下生成，因而较稳定，此外，在贫钙状态，析出晶体较为粗大，而在富钙状态，析出晶体较为细小。     

纯钛阳极氧化伴水热处理后羟基磷灰石薄涂层种植体的实验研究

目的：了解阳极氧化伴水热处理后纯钛种植的体内成骨效应。方法：36枚纯钛种植体采用4种表面处理,随机植入12只兔股骨内,分别在术后4周、8周、16周取出带种植体骨块制作磨片,观察界面新生骨情况以及抛光、水热处理种植体术后8周的界面超微结构,行表面能谱分析。结果：术后8周,阳极氧化伴水热处理种植体表面编码骨的转化和成熟较快,至16周时界面几乎无编织骨和剥脱的羟基磷灰石碎片,种植体表面的钙,磷含量在种植后增加,抛光种植体表面钙、磷含量增加不明显。结论：纯钛经阳极氧化伴水热处理后,可以加快种植表现编织骨转化为板层骨,从而可能促进种植区的早期愈合,薄涂层特有的优越性尚待进一步研究。     

采用仿生溶液法在纯钛表面制备羟基磷灰石涂层的研究

目的：初步了解在仿生溶液中，纯钛表面沉积羟基磷灰石涂层的技术路线。方法：商业纯钛片经抛光，喷砂，清洗，酸碱腐蚀氧化及加热等预处理后，先后置于37℃的仿生液及1．5倍仿生液中16天。结果：酸碱处理后钛片表面呈现均匀多孔的网状结构，热处理后网状结构更致密，置仿生溶液中16天后，在钛片表面呈现结晶物，X射线衍射分析证明其为羟基磷灰石。结论：预处理后可能在纯钛表面形成多孔网状结构的氧化膜，经仿生液处理后在氧化膜表面沉积了羟基磷灰石涂层。     

预阳极氧化和水热沉积复合法制备纯钛表面羟基磷灰石涂层

目的：研究阻止金属离子向体液中游离和改善纯钛的生物相容性。方法：采用预阳极氧化及水热沉积复合法对纯钛试件进行生物改性。用X射线衍射(XRD)及SEM和SEM附带的能谱(EOS)对涂层的组成和结构进行分析。结果：预氧化后，纯钛表面生成了致密的纯锐钛矿型二氧化钛薄膜，它可诱导骨样羟基磷灰石的形成，促进细胞的黏附和生长，还能阻止内层金属离子的溶出。结论：水热沉积后在致密的二氧化钛薄膜上生成了结晶状态完好、均匀多孔的骨样羟基磷灰石涂层，可提高纯钛植入体的生物相容性和生物活性。     

釉基质蛋白对碱热处理纯钛表面磷灰石生成的影响

目的：研究釉基质蛋（EMPs）对碱热处理纯钛表面磷灰石涂层生成的影响。方法：采用乙酸法提取猪EMPs。纯钛片碱热处理后,在含不同浓度EMPs（0、50、100、150、200μg／mL）的模拟体液中浸泡1周、2周后取出。扫描电镜观察表面形貌,x射线衍射分析晶相结构。结果：各组试件表面均有类骨磷灰石（CHA）生成。EMPs浓度为50、100μg／mL时,钙磷涂层的沉积受到抑制;EMPs浓度为150、200μg／mL时,钙磷涂层的沉积增强,且涂层粗糙度增加,有直径约300～600nm孔隙生成,晶体呈（002）方向择优取向生长。结论：EMPs对碱热处理纯钛表面磷灰石生成的影响与浓度密切相关,较高浓度EMPs可促进钛表面生成CHA,并改变磷灰石晶体的形态与生长方向。     

种植体表面TiO2/HA梯度涂层的生物相容性研究

目的：通过观察大鼠成骨细胞（osteoblast,OB）在微弧氧化（micro-arc oxidation,MAO）和水热处理形成的TiO2/HA梯度涂层表面的粘附和增殖等情况,评价微弧氧化陶瓷膜表面的生物相容性及微弧氧化-水热处理工艺应用于钛植入材料表面处理的可行性。方法：将纯钛试件共60枚分为微弧氧化处理组（M组）、微弧氧化-水热处理组（M-H组）和纯钛对照组。采用扫描电镜（scanning electron microscopy,SEM）观察表面形貌并用X线衍射（X-ray diffraction,XRD）对其进行成分分析。然后对不同时间点OB细胞在各组材料表面的附着、生长、增殖情况以及碱性磷酸酶（alkaline phosphatase,ALP）活性进行检测,并对实验结果进行统计分析。结果：微弧氧化处理后试件表面呈现多孔状,主要为锐钛矿型TiO2,也包含金红石型TiO2。经过后续水热处理,从扫描电镜照片可以看到试件表面析出一层白色柱形结晶体,同时XRD谱线出现了羟基磷灰石的衍射峰。试件与OB细胞共培养后可见细胞在材料周围生长良好,培养5d后,改性两组的材料表面细胞增殖比纯钛组及空白对照组明显增多。培养7d后,M组和M-H组细胞ALP活性大幅提高,各组间比较均有统计学差异。结论：MAO及水热处理后的TiO2/HA梯度涂层表面能有效提高OB细胞的早期粘附、增殖及ALP活性。     

牙种植体纳米含氟羟基磷灰石涂层材料制备实验研究

目的 探讨用溶胶-凝胶法制备出的纳米含氟羟基磷灰石（nFHA）材料用于纯钛表面涂覆的理论依据。方法 本实验于2010年1-5月在中南大学粉末冶金研究院完成。采用溶胶-凝胶法制备nFHA和羟基磷灰石（HA）材料,通过X线衍射（XRD）、透射电镜（TEM）表征其物相组成及颗粒大小,扫描电镜（SEM）观察涂层在纯钛表面形貌。结果 XRD检测结果显示,运用溶胶-凝胶法可制备出nFHA材料,氟离子进入HA晶体中,以nFHA固溶体形式存在。TEM显示,nFHA晶体呈短棒状,粒径大部分在100 nm以下,符合纳米级别。SEM显示,热处理后的nFHA涂层,为多孔形貌,相互形成穿通结构,颗粒均匀分布,无明显裂纹。结论 （1） 采用溶胶-凝胶法可制备出nFHA涂层材料;（2） nFHA较HA在钛基表面涂层可形成更佳的孔隙结构。     

紫外线光照射促进微弧氧化纯钛诱导磷灰石形成及细胞矿化

目的评估紫外线照射效应对微弧氧化纯钛诱导磷灰石形成及细胞矿化的影响。 方法Ⅱ级商用纯钛片进行微弧氧化（MAO）处理,作为空白对照组,记为MAO;微弧氧化结合紫外线（UV）照射处理2 h的钛片作为实验组,记为MAO+UV 2 h。采用扫描电镜（SEM）观察钛片浸泡在DMEM/F12培养液中材料表面磷灰石形成情况;将钛片与大鼠脂肪间质干细胞矿化诱导条件下共培养,观察细胞矿化情况。 结果浸泡在培养液中21 d后,MAO组仅在SEM高倍镜下见少量散在微小磷灰石结晶颗粒;MAO+UV 2 h组颗粒明显增大增多且叠层沉积,除微弧氧化形成的孔径外周高点外,氧化膜层几乎全部被磷灰石晶体层覆盖,且孔径内沉积大量晶体使孔径明显缩小。SEM观察细胞矿化物的形成情况,发现MAO组未见明显矿化物形成,但MAO+UV 2 h组细胞材料表面可见较多针状结晶,能谱分析（EDS）提示为磷灰石结晶。 结论紫外线照射可增强微弧氧化纯钛表面在体外诱导磷灰石沉积的能力且促进脂肪间质干细胞的体外矿化。     

纳米羟基磷灰石骨细胞相容性的研究

目的　比较纳米羟基磷灰石(nHA)和常规羟基磷灰石(cHA)骨细胞相容性方面的差异。方法　采用化学 沉淀法制备nHA粉体,采用压制成型和无压烧结工艺制备nHA与cHA的块体材料。建立Wistar乳鼠体外原代分离 培养成骨细胞实验模型,将细胞分别接种于nHA与cHA的表面,观察1、3、5、7 d时细胞在材料表面的形态变化和 增殖情况。结果　制备的nHA与cHA的平均粒径分别为55 nm和780 nm。在nHA与cHA材料表面,成骨细胞能 正常粘附、伸展、增殖,附着形态未见明显的差异。与cHA比较,成骨细胞更易于在nHA表面吸附。结论　与相应 的cHA比较,成骨细胞与nHA间具有更好的骨细胞相容性。     

羟基磷灰石溶解机理的研究

目的:研究羟基磷灰石(Hap)的溶解机理。方法:采用分子动力学对HAp在水分子层作用下的溶解过程进行计算。对HAp在不同pH值溶液中的表面Zeta电位进行测定,并进行HAp去除Pb2+实验,由此来对计算结果进行讨论和验证。结果:HAp在水溶液的溶解过程中表面羟基发生脱离溶入水中;表面Ca2+由于羟基的脱离,减少了与HAp结构的联系,并由表面溢出至水层中;次表面羟基发生倒转与c轴成一定角度;表面磷酸基团也脱离出来成为磷酸根离子,次表面磷酸基团的磷氧键向下倾斜;溶解作用使得HAp的表面为负电位。结论:所获溶解机理是合理的,羟基在HAp在水溶液中的溶解起着重要的作用。     

Anodic electrodeposition of iridium oxide films

IrO_x films have been deposited on conducting transparent SnO₂-coated glass substrates with sheet resistance of about 10 Ω/□ by electrochemical oxidation of soluble iridium species in a basic aqueous medium. Before being efficient for deposition, the iridium-containing solutions have to be aged for a minimum time which is determined by UV-visible spectrophotometry. The IrOx films prepared following the procedure described show cyclic voltammograms similar to those of anodic iridium oxide films (AIROF)s grown on iridium surfaces, i.e. one or two redox systems depending on whether the pH of the electrolyte is below or above 5. The IrOx films could be completely dissolved in boiling hydrochloric acid solutions and consequently their iridium contents were very precisely determined. These analyses clearly showed that a total of two electrons/iridium are exchanged in a basic medium, i.e. one electron/iridium for each redox system as the charges involved in both systems are nearly the same. The optical properties of the IrOx films were monitored in situ under potential cycling. The more cathodic redox system was assigned to Ir(III)/Ir(IV), it exhibits an electrochromic behavior characterized by a complete transparency of the reduced state and a coloration factor approaching 18 cm² C^?1 at 633 nm. On the other hand, no significant modulation of the transmitted signal at 633 nm was detected for the second redox system which was observed only in basic media and attributed to Ir(IV)/Ir(V).     

Pantomography of Flat Layers

The effects of in vivo zinc deficiency and restricted food intake, on the in vitro synthesis of glycosaminoglycans of rib cartilage were studied in the rat. ³⁵S-sulfate and ¹⁴C-glucosamine were used as precursors. The glycosaminoglycans were separated on microcolumns and specific radioactivities determined for the different fractions.

Chemical analyses showed that zinc deficiency or reduced food intake did not cause any qualitative or quantitative changes in the glycosaminoglycans. The radioassays indicated that zinc deficiency and reduced food intake, alone or combined, caused a somewhat lowered synthetic rate of chondroitin sulfate. In the discussion it is underlined that it seems difficult to determine conclusively the importance of zinc for the formation of the mucopolysaccharides through further in vivo deficiency studies, because of the difficulties to control and evaluate the inanition factor.     

羟基磷灰石种植体的动物实验研究

分别在兔子左下切牙远端人工制备牙槽窝,植入羟基磷灰石生物陶瓷种植体,分别于1、3、6个月处死兔子,制成标本在光镜及电镜下观察。种植体与骨组织1个月时为纤维性结合;3个月时大部分为骨性结合,少部分为纤维性结合;6个月时为骨性结合,有较多骨组织长入种植体内。另再拔除兔子上前牙,即刻将种值体植入牙槽窝内,同法观察。1个月时大部分为纤维性结合,根尖为骨性结合;3个月时为骨性结合,有较多骨组织长入种植体(多孔型)内;6个月时为骨性结合。生理性牙槽窝有利于种植体与周围组织的结合与稳固;多孔型比致密型固位快,可能与表面微孔有关;种植体与骨组织的结合是一种正合关系。     

多孔性碳酸化羟基磷灰石支架材料体外可吸收性测定

目的：通过体外实验对不同组分多孔碳酸化羟基磷灰石（PCHA）支架材料的可吸收性进行评价。方法：将制得的不同孔隙率、不同碳酸根含量的15种PCHA样本（n=3）,置于100 mL、pH=4.0的醋酸钠缓冲液（模拟破骨细胞造成的酸性环境）中;对照组为羟基磷灰石（HAP）及脱脂处理过的牛松质骨。每组材料均分别在浸泡1、4、8 h或1、2、3、4、5、7 d后,取0.1 mL浸提缓冲液进行Ca2+浓度测定,以评价材料的可吸收性。结果：各PCHA实验组和牛松质骨对照组的Ca2+浓度,均随浸泡时间增加而增高,HAP对照组无明显变化。随着碳酸化程度和孔隙率的增加,PCHA的溶解速率也随之增加。其中7-40组、7-60组、8-40组、8-60组、8-70组、9-70组在各时间点测得的PCHA溶出钙离子浓度,与对照牛松质骨对照组差异均无统计学意义（P＞0.05）,以上几组PCHA与牛松质骨具有最相似的可吸收性。结论：PCHA材料表现出良好的可吸收性,碳酸化的程度和孔隙率的大小是影响其可吸收性的重要因素。     

Hydroxyapatite solubility in simple inorganic solutions

OBJECTIVE: To use solid titration and laser-scattering end-point detection to determine the hydroxyapatite (HAP) solubility isotherm at 37 degrees C in a plain KCl solution, with CO(2) present, and with additional phosphate. DESIGN: Pulverised HAP solid was used to perform a titration to saturation. A very sensitive detector capable of detecting the light scattered at small forward angles from a laser beam was adopted to monitor the onset of precipitation (or failure to dissolve) near the equilibrium point. Each addition of HAP solid caused a step increase in scattered light and this signal decreased quasi-exponentially with time. When a steady but elevated scattering was obtained, small portions of 1M HCl were added to lower the pH by about 0.5-2 units, according to need, to dissolve excess solid and allow a further titration. The scatter signal and pH data, plotted against the amount of HAP added, were used to estimate the actual end-point by interpolation and thus construct each point on the solubility isotherm. RESULTS: The solubility isotherm for HAP in plain KCl solution in the absence of CO(2) obtained now differs substantially from the results of previous solubility studies (i.e. much lower). The increase in solubility due to CO(2) reported earlier was confirmed, while the effect of excess phosphate was found to be to increase the apparent solubility of HAP, contrary to elementary mass-action expectations. CONCLUSIONS: The solid titration method is a more reliable approach than that of conventional excess solid method with respect to the determination of the HAP-carrying capacity. The solubility of HAP appears to be substantially lower than previously reported, and a reconsideration of all aspects of the system is warranted.     

Hydroxyapatite cement in pediatric craniofacial reconstruction

The gold standard for closing small cranial defects is autogenous bone: iliac crest, rib, or split calvarial grafts. Autogenous grafts result in donor site morbidity, increased operative time, blood loss, and additional cost, and they are limited in quantity. Hydroxyapatite cements are alternative bone substitutes that eliminate these restrictions. Although the use of hydroxyapatite is well accepted in completely developed crania, its use in the growing pediatric skull is limited. The purpose of the current study was to address the safety and long-term efficacy of this bone substitute for the repair of craniofacial bone defects in the growing pediatric skull. Safety is measured dually by resistance of bone substitute to infection and its tolerability by lack of a foreign body reaction. Efficacy is evaluated as structural skull integrity, volume stability with time, aesthetic quality, and most importantly, the ability to integrate adequately into a growing cranium without subsequent deformity or complications. This is a retrospective review of all pediatric patients at the authors' institution who underwent reconstruction of cranial defects using hydroxyapatite cement between May 1997 and March 2001. Eight patients who underwent 11 operations between the ages of 25 and 100 months (mean, 55 months) were followed up between 23 and 72 months (mean, 38 months). No mortalities or significant morbidities were encountered in the study population. It has been the authors' experience that hydroxyapatite cement is both biocompatible and resistant to infection when used in sites not contiguous with sinus mucosa; and that it is a good alternative to autogenous bone in pediatric craniofacial reconstruction.