纳米羟基磷灰石表面阿伦膦酸钠和I型胶原蛋白复合膜对成骨细胞形态和增殖的影响

目的: 探讨经化学结合阿伦膦酸钠(alendronate sAium,ALN)和I型胶原蛋白(collagen type I,COL I)修饰的纳米羟基磷灰石(nano-hydroxyapatite,nHA)涂层对成骨细胞在其表面黏附、生长和增殖的影响。方法: 建立nHA涂层、nHA/ALN、nHA/COL I、nHA/ALN/COL I和nHA/COL I/ALN复合膜,将成骨细胞接种于复合膜表面,分别培养7 d和14 d,扫描电镜观察成骨细胞在不同膜层表面的黏附形态的变化,WST-1法对各膜层表面细胞数量进行定量检测。结果: 成骨细胞在nHA/ALN/COL I和nHA/COL I/ALN复合膜表面的增殖活性最高(P<0.05),扫描电镜观察成骨细胞在nHA/ALN/COL I和nHA/COL I/ALN复合膜表面生长状态优于其他膜层,在COL I膜直接作用下,成骨细胞伸展更为完全,并有较多伪足突起和微绒毛结构呈分化表型。结论: 将ALN和COL I 修饰于nHA表面能够协同促进成骨细胞的黏附和增殖。nHA/ALN/COL I复合膜促进成骨细胞的黏附与分化。     

表面梯度涂层纯钛植入体骨结合和骨诱导能力的动物实验研究

目的：观察纯钛植入体表面用低温烧结技术生成羟基磷灰石/生物玻璃( nHA/BG)梯度涂层植入动物体内的骨结合和骨诱导能力。方法：将nHA/BG按比例混合,应用低温烧结技术在圆柱形纯钛植入体表面形成梯度涂层,模拟体液浸泡后产生活性纳米结构。将梯度涂层实验植入体和纯钛对照植入体分别植入12只新西兰兔股骨髁。术后不同时间行X线摄片,切取标本;硬组织切片,用四环素荧光标记观察植入体周围新生骨形成量;苦味酸-品红染色观察植入体-骨界面骨沉积和结合情况。结果：低温烧结和模拟体液浸泡制备的nHA/BG梯度涂层为纳米化多孔粗糙结构,动物实验示,梯度涂层植入体与周围新生骨明显增多,骨整合良好。结论：梯度涂层和模拟体液浸泡制备的植入体涂层有良好的骨结合和骨诱导能力。     

聚多巴胺仿生掺锶羟基磷灰石涂层的制备及对骨髓间充质干细胞生物学特性的影响

目的:通过修饰聚多巴胺并结合仿生矿化法在钛合金表面制备掺锶羟基磷灰石涂层,体外评价该复合材料对大鼠骨髓间充质干细胞生物学特性的调控作用.方法:采用两步法制备掺锶羟基磷灰石涂层.采用扫描电镜、X射线光电子能谱、X射线衍射图谱、拉曼光谱和接触角测量等材料表征证实钛合金表面聚多巴胺仿生掺锶羟基磷灰石涂层的形成.将大鼠骨髓间充...     

纳米羟基磷灰石-壳聚糖复合材料对NIH3T3细胞粘附增殖的影响

目的制备纳米羟基磷灰石-壳聚糖(nano hydroxyapatite-chitosan,nHA/CS)复合膜和三维立体支架,观察复合材料的两种状态对成纤维细胞粘附形态的影响。方法制备nHA/CS复合膜和HA/CS复合膜,然后将两组膜分别与NIH3T3细胞共培养,倒置显微镜下观察细胞在材料表面粘附形态同时进行粘附细胞数量的测定;冷冻干燥法制备nHA/CS三维支架,将HA制成同样大小的圆盘状,然后将NIH3T3细胞分别与两组材料共培养,扫描电镜观察细胞在两种材料表面的粘附形态同时进行细胞粘附数量的测定和能谱分析。结果与NIH3T3细胞共培养5、7d后nHA/CS组细胞粘附数量高于HA/CS组和HA组,差异有显著性。结论nHA/CS复合材料有促进细胞粘附增殖作用。     

数字化载葡萄糖酸氯己定PLA/nHA复合支架的制备及性能分析

目的:探讨负载葡萄糖酸氯己定壳聚糖纳米球(CSn-CG)3D打印多孔聚乳酸/纳米羟基磷灰石(PLA/nHA)支架的理化性能、细胞相容性及抗菌活性。方法:借助离子交联法,完成CSn(空白壳聚糖纳米球)与CSn-CG的制备,借助透射电镜(TEM)对纳米球形态进行观察。利用数字化设计3D打印技术,以PLA和nHA为原料,制备PLA/nHA支架。以浸泡法搭载CSn、CSn-CG,实验分为PLA/nHA组、PLA/nHA/CSn组、PLA/nHA/CSn-CG组3组。针对各组支架,通过扫描电镜(SEM)、X射线光电子能谱仪(XPS)、傅立叶红外光谱仪(FTIR)、X射线衍射(XRD)进行表征分析。体外释放实验评估支架的缓释性能,CCK-8法评估支架的生物相容性,琼脂扩散法检测支架的抗菌效果。采用SPSS25.0软件包对所得数据进行统计学分析。结果:CSn-CG为大小均匀的纳米球。SEM下发现,各组支架均为三维网状结构,孔径规则。体外释放结果表明,CG能够自支架内低速缓慢释放,用时30 d。CCK-8结果显示,PLA/nHA/CSn-CG组可促进小鼠前体成骨细胞(MC3T3-E1)增殖。体外抑菌实...     

微弧氧化钛基体含Si、Ca涂层的表征及植入兔胫骨影像学和力学性能研究

目的:观察及评价含Si、Ca涂层的微弧氧化钛基体的涂层表征及其骨结合性。方法:在纯钛基体上通过微弧氧化(microarc arc oxidation MAO)的方法制备含Si、Ca元素的涂层并对其进行表征。根据国家标准将该材料植入兔胫骨,在植入后4、8、12周进行X射线及力学性能评价。结果:涂层表面成功的引入了Si、Ca元素。X射线显示材料植入后无炎症效果,力学性能测试表明该材料与骨的结合力高于纯钛种植体。结论:含Si、Ca涂层的微弧氧化钛种植体与骨结合性能良好。     

PRP/nHA/Co复合材料修复牙周组织缺损的应用研究

目的:将富含血小板血浆(PRP)与纳米羟基磷灰石(nHA)/胶原(Co)复合,通过动物实验评价复合材料的生物学性能,充分发挥每种材料的优点,使之成为组织工程学中一种新型替代骨组织的生物活性材料和支架材料。方法:将nHA和胶原复合并将其制备成nHA/Co复合膜后加入PRP制备成PRP/nHA/Co复合材料。实验动物制备大小为5mm×5mm的牙周缺损,右侧为实验组,在相应牙位置入PRP/nHA/Co复合膜材料;左侧对照组不放置任何材料。术后第4、8周行64排CT片和组织病理检查,观察成骨效果。结果:动物生存状态良好,牙龈附着愈合良好。CT观察实验组出现新生牙槽骨,骨嵴基本恢复到原来高度;对照组牙槽嵴高度未见增加。HE染色观察对照组缺损处周围见大量炎性细胞,纤维组织增生,无软骨形成并有大量上皮长入;实验组可见大量新生的牙槽骨。结论:PRP/nHA/Co复合生物膜可以作为组织工程学中一种新型替代骨组织的生物活性材料和支架材料。     

疏水性硅涂层对牙科氧化锆陶瓷的表面改性研究

目的:在牙科氧化锆陶瓷表面制备疏水性硅涂层,为提高其与树脂的粘结耐久性提供理论基础.方法:以正硅酸乙酯(tetraethoxysilane,TEOS)为硅源,甲基三甲氧基硅烷(methyltrimethoxysilane,MTMS)为改性剂,通过溶胶-凝胶法在牙科氧化锆陶瓷表面制备硅涂层.扫描电镜观察涂层形貌,X射线能...     

微弧氧化联合溶胶-凝胶工艺制备钛表面复合生物涂层的研究

目的探讨微弧氧化联合溶胶-凝胶工艺制备钛表面复合生物涂层。方法钛片根据表面处理工艺不同分为5组:对照组,MAO(微弧氧化组),MAO+Sol/gel(微弧氧化+溶胶-凝胶组),MAO+Sol/gel-LowZn(微弧氧化+溶胶-凝胶低锌组),MAO+Sol/gel-HighZn(微弧氧化+溶胶-凝胶高锌组)。利用扫描电镜(SEM)观察涂层表面形貌,X射线能谱分析仪(EDX)和X射线衍射仪(XRD)分析元素分布和成分,测厚仪测量涂层厚度;粗糙度测试仪测量表面粗糙度。结果 SEM下可见MAO组钛表面粗糙多孔,联合溶胶-凝胶处理后,钛表面更加平整紧密,EDX得出MAO+Sol/gel组钙磷元素的质量百分比分别为25.00%和15.49%,MAO+Sol/gel-Low Zn组和MAO+Sol/gel-High Zn组钙、磷、锌元素的质量百分比分别为22.87%、15.01%、1.82%与18.66%、15.60%、7.45%,XRD得出MAO+Sol/gel组、MAO+Sol/gel-Low Zn组和MAO+Sol/gel-High Zn组均可见特征性羟基磷灰石(HA)峰和Ca3(PO4)2峰,MAO+Sol/gel-High Zn组表面涂层厚度最高(10.40±0.49)μm(P<0.05),MAO+Sol/gel组表面粗糙度最高(1.17±0.10)μm(P<0.05)。结论应用微弧氧化联合溶胶-凝胶工艺,可在钛金属表面制备出HA涂层,并通过调节溶胶凝胶中Zn(NO3)2·6H2O的含量,制备出HA和不同含量锌离子的复合生物涂层。经过两种不同工艺联合处理后,钛表面涂层厚度逐渐增加,而粗糙度随着溶胶凝胶中锌离子的增加逐渐降低。     

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目的探讨在金属钛表面类骨磷灰石上制备胶原蛋白与羟胆固醇复合生物活性涂层的可行性。方法研究于2013年12月在清华大学材料学院进行。采用酸-碱热处理结合仿生矿化沉积的方法在钛表面构建一层均匀的类骨磷灰石,采用物理吸附方法将胶原蛋白和羟胆固醇共同或单一固定在具有类骨磷灰石涂层的钛表面,构建钛表面的复合涂层。结果场发射扫描电镜和X射线衍射分析验证了钛表面的类骨磷灰石;衰减全反射-傅里叶变换红外光谱和X射线光电子能谱定性证明了胶原蛋白被成功固定在具有类骨磷灰石涂层的钛表面上;微二喹啉甲酸法和高效液相色谱法可测定固定在复合涂层上的胶原蛋白和羟胆固醇含量。结论通过酸-碱热处理和仿生矿化沉积方法可在钛表面构建一层均匀的类骨磷灰石,通过物理吸附方法可成功将胶原蛋白和羟胆固醇共同或单一固定在具有类骨磷灰石涂层的钛表面,构建钛表面的复合涂层。     

溶胶凝胶自组装法硅涂层对氧化锆陶瓷与树脂短期粘结强度的影响

目的　评价溶胶凝胶自组装法硅涂层对氧化锆陶瓷与树脂短期粘结强度的影响。方法　加工56 个氧化锆瓷块并随机分为4 组,分别对粘结面进行以下处理：A组：硅烷偶联剂;B组：溶胶凝胶浸涂1层硅涂层+硅烷偶联剂;C组：溶胶凝胶自组装2层硅涂层+硅烷偶联剂;D组：溶胶凝胶自组装3层硅涂层+硅烷偶联剂。制作56 枚光固化复合树脂圆柱并用树脂水门汀粘结于预处理后的氧化锆瓷块上,水浴24 h 后测试剪切粘结强度。以扫描电镜和表面能谱分析对不同表面处理的氧化锆进行表征分析,体视显微镜记录样品断裂模式。结果　A组到D组各组剪切粘结强度值分别为（3.05±0.26）MPa,（6.83±0.33）MPa、（10.51±0.58）MPa和（7.72±0.35）MPa。除B组和D组无统计学差异外,其余各组之间均具有统计学意义(P=0.000)。其中溶胶凝胶自组装2层硅涂层获得的剪切粘结强度值最大。结论　溶胶凝胶自组装法硅涂层可以提高氧化锆陶瓷表面粘结强度,其中溶胶凝胶自组装2层硅涂层组的效果最好。     

A new technique for assessing hybrid layer interfacial micromorphology and integrity: two-photon laser microscopy

PURPOSE: This study describes a two-photon laser fluorescence microscopy technique developed to evaluate the interfacial micromorphology of the hybrid layer in bonded restorations. MATERIALS AND METHODS: Micropermeability of the hybrid layer was characterized by means of simultaneously contrasting a dye-containing adhesive with a differently colored dye placed into the pulp chamber and allowed to diffuse toward the different-colored hybrid layer. A fluorescent red dye (rhodamine B) was incorporated into a commercial dentin bonding agent. Class I preparations (margins in enamel) were made on extracted human third molars. The teeth were restored using conventional methods: bonding agent, composite, finishing, and polishing. An aqueous solution of a yellow/green dye (fluorescein) was then placed into the pulp chamber for 3 h, allowing time to diffuse toward the different-colored bonded interface. The teeth were then embedded, sectioned, and microscopically analyzed using two-photon laser microscopy at 40X magnification. RESULTS: Subsurface fluorescent imaging using this technique enabled interfacial micromorphology to be characterized at submicrometer resolution and provided high-contrast images. The quality of surrounding structures and potential presence of gaps were also precisely assessed. CONCLUSION: Two-photon laser microscopy provided high quality, high-resolution images of the bonded interface and surrounding areas, allowing accurate qualitative and quantitative analysis of the structure and integrity of the hybrid layer.     

Effects of exogenous collagenase and cholesterol esterase on the durability of the resin-dentin bond

PURPOSE: The purpose of this work was to determine microtensile dentin bond strengths (microTBS) of dentin-resin composite bonds after three-month storage in artificial saliva containing either collagenase (COL) or cholesterol esterase (EST). The null hypothesis tested is that the resin-dentin bond strength is equivalent for each storage medium at the tested storage times. MATERIALS AND METHODS: Resin composite was bonded to occlusal dentin, and microTBS specimens were formed and stored in the artificial saliva, COL, EST, or synthetic oil. After 24 h and 12-week storage, microTBS was determined and failure modes were characterized by SEM. The interfacial ultrastructure was evaluated by transmission electron microscopy as unstained and stained sections (phosphotungstic acid/uranyl acetate). Statistical analysis was performed by ANOVA and Weibull survival analyses at the 0.05 level of statistical significance. RESULTS: There were significantly weaker bond strengths after 12 weeks for all experimental storage media (p < 0.001). Artificial saliva containing EST lowered bond strengths to a significantly greater extent than did COL after 12 weeks of storage, while no difference between these groups could be discerned after 24 h. Therefore, the null hypothesis of this experiment is rejected. CONCLUSION: Exogenous enzymatic challenge to resin-dentin bonds decreased bond durability only with EST. However, when further challenges to ideal infiltration of the comonomers into the hybrid layer were carried out using inadequate removal of solvent, additional alterations in hybrid layer ultrastructure were discerned by TEM that may represent different potential degradative processes. The contribution of endogenous enzymatic challenges to the primary degradative process, ie, hydrolysis, is unknown and deserves continued attention.     

nHA/BG涂层与Bio-Oss骨粉修复种植体骨缺损的实验研究

目的:评价生物玻璃/纳米羟基磷灰石(nHA/BG)涂层与Bio-Oss骨粉在种植体骨缺损中引导骨再生的效果。方法:选取6只Beagle犬,拔除两侧下颌前磨牙。3个月后预备种植窝,同时颊侧制造裂隙状骨缺损(2.25 mm×3 mm×4 mm)。按照分组植入种植体和骨粉,A组为nHA/BG+Bio-Oss,B组为nHA/BG+血凝块愈合,C组为微米级HA+Bio-Oss。术后2周、处死前2周和3 d分别进行四环素、钙黄绿素和茜素红荧光标记。术后8周和16周处死动物,行大体观察和组织学测量。采用SPSS13.0软件包对数据进行统计学分析。结果:3组骨-种植体结合率(BIC)在8周时分别为30%、18%、21%,16周时分别为61%、53%、46%;缺损区新骨面积(RA)在8周时分别为(2.1±0.6)mm3、(1.4±1.0)mm3、(0.6±0.1)mm3,16周时分别为(4.2±0.7)mm3、(2.2±1.2)mm3、(1.2±0.6)mm3。各组8周与16周的BIC和RA相比均有显著差异(P<0.05);8周时,A、C 2组的BIC和RA相比有显著差异(P<0.05),16周时,A、B 2组的RA相比有显著差异(P<0.05)。结论:在种植体周围2.25 mm骨缺损区,nHA/BG涂层能促进种植体-Bio-Oss替代骨-骨的骨结合。     

Formation of the first monolayers of CdTe on Au(111) by electrochemical atomic layer epitaxy (EC-ALE): studied by LEED,Auger, XPS,and in-situ STM

The two-step alternated electrodeposition of Cd and Te atomic layers to form CdTe monolayers, electrochemical atomic layer epitaxy (EC-ALE), was studied on Au(111) using Auger electron spectroscopy (AES), low energy electron diffraction (LEED), in-situ scanning tunneling microscopy (STM), and X-ray photoelectron spectroscopy (XPS). Well ordered (√7×√7)R19.1°-CdTe and (3×3)-CdTe structures were formed using either Te or Cd as the first layer, and model structures are proposed for both. STM images suggest that previously proposed hexagonal structures based on a plane of zinc blende CdTe may be incorrect. A chain structure is suggested to account for the (√7×√7)R19.1°, based on 3/7 (0.43) ML each of Cd and Te. The (3×3)-CdTe structure results from the deposition of a CdTe sandwich: first an atomic layer of Cd on Au, followed by a layer of Te, and then a second Cd layer. Based on this three layer model for the (3×3), a three step deposit was formed, starting with Cd, then Te, and finally Cd. This resulted in an excellent quality LEED pattern, suggesting a well-ordered (3×3)-CdTe deposit and strongly supporting the proposed model. The importance of deposit stoichiometry was also investigated using STM, which indicated that too low a coverage in the first atomic layer resulted in cluster formation and the degradation of surface morphology.     

Effect of (-)-epigallocatechin gallate on electrochemical behavior and surface film composition of Co-Cr alloy used in dental restorations

The aim of this study was to investigate the electrochemical behavior of Co-Cr alloy in artificial saliva containing (-)-epigallocatechin gallate (EGCG) and to characterize the composition and structure of the passive film formed by potentiodynamic polarization.Electrochemical measurements ranked the corrosion resistance of Co-Cr dental cast alloy as follows when exposed to artifi cial saliva containing different concentrations of EGCG: 4.0 g/L<2.0 g/L<0 g/L<0.5 g/L<1.0 g/L. This showed that the concentration of EGCG in artificial saliva affected the corrosion behavior of Co-Cr alloy. X-ray photoelectron spectroscopy (XPS) results revealed that theoutermost surface layer on Co-Cr alloy was mainly composed of Cr2O3 and EGCG-Cr (III) ion complex, which were formed by redoxand complex formation reactions respectively. When the redox reaction was dominant, Co-Cr alloy exhibited high corrosion resistancein EGCG-containing artificial saliva. On the contrary, when the complex formation reaction was dominant, Co-Cr alloy exhibited low corrosion resistance.