牙科修复用BiOIO3/g-C3N4复合纳米光催化剂的制备与表征

目的 研究不同剂量NaOH条件对制备BiOIO3/g-C3N4复合纳米光催化剂的结构形貌及其可吸收光谱的影响,为研制适用于口腔修复纳米光催化功能性材料提供依据.方法 水热法制备BiOIO3/g-C3N4,通过XRD(X射线衍射仪)、SEM(扫描电镜图)和UV-vis(紫外-可见光吸收光谱)对其形貌、结构、分子组成和理化...     

钴铬合金表面铁离子掺杂二氧化钛膜的制备

目的在钴铬合金表面制备Fe3+掺杂二氧化钛薄膜。方法采用溶胶-凝胶法在钴铬合金表面制备Fe3+掺杂二氧化钛膜,利用扫描电镜、原子力显微镜、X射线衍射仪、傅立叶红外光谱仪、X射线能谱仪分别表征薄膜的表面和横断面形貌、晶相结构及元素成分,并通过划痕法和磨损实验测试膜基结合强度及薄膜的耐磨性。结果钴铬合金试样表面形成一层厚约267~310 nm、平整致密的金黄色透明薄膜,薄膜成分为锐钛矿型二氧化钛,其主要元素成分有O、Ti、Fe。膜基结合力平均值为68.37 N,同等磨损实验条件下,镀膜试样的失重量约为未镀膜者的2/5。结论溶胶-凝胶法在钴铬合金表面制备Fe3+掺杂二氧化钛薄膜光滑平整,具有良好的膜基结合力与临床应用价值。     

不同纳米颗粒二氧化钛的细胞相容性研究

目的:探索二氧化钛发挥最佳生物学效应的纳米晶尺寸。方法:采用MTT法观察成骨细胞在材料表面的增殖情况,细胞培养第5d时对碱性磷酸酶活性进行检测,并用SEM观察第3d时细胞在材料表面的附着形态。结果:成骨细胞在20nm组材料表面的细胞增殖数显著高于其它各组,并具有更好的细胞伸展形态;而200nm组材料碱性磷酸酶表达最高。结论:不同纳米尺寸二氧化钛的细胞相容性存在差别。     

纳米二氧化钛涂层种植体材料的抗菌活性实验研究

目的:通过研究纳米二氧化钛(Nano-TiO2)种植体表面涂层材料的抗菌性能,为种植体表面材料的研发提供实验依据。方法:采用种植体周围炎可疑致病菌株牙龈卟啉单胞菌(Pg)、血链球菌(Ss)、金黄色葡萄球菌(Sa),以TC4(钛合金)为对照组比较两种材料的抗菌效果,并采用时效法测试时间长短对材料抗菌活性的影响。结果:采用贴膜法对Nano-TiO2涂层试件抗菌效果进行定量测试,对Pg、Ss、Sa的抗菌率分别为94.02%、99.34%、98.72%,实验组与对照组细菌量差异有统计学意义(P<0.05)。通过时效法测试时间长短对材料的影响,结果显示随着时间的推移,同一材料表面细菌量的差异无统计学意义(P>0.05)。结论:纳米二氧化钛涂层材料对3种可疑口腔致病菌均具有很好的抗菌效果,其抗菌性能优于TC4材料;其抗菌效果无时间依赖性,具有一定的抗菌稳定性和持久性,对于种植体周围炎的防治具有积极作用。     

二氧化钛纳米颗粒的成骨细胞毒性研究

目的研究二氧化钛纳米颗粒(TiO2-NPs)对成骨细胞生长的细胞毒性及其机制,为研发新型钛基骨植入体提供科学依据。方法建立TiO2-NPs与成骨细胞MC3T3-E1的共培养体系,研究TiO2-NPs对成骨细胞的细胞毒性效应、氧化应激反应及细胞凋亡的改变。结果 TiO2-NPs可引起成骨细胞活力下降、激发细胞氧化应激反应,同时可诱导细胞凋亡。结论TiO2-NPs可引起成骨细胞的毒性反应,机制主要为引起细胞的氧化应激反应和p53调控的细胞凋亡。本研究对于了解TiO2-NPs的成骨细胞毒性及机制具有重要的理论意义,为探讨TiO2-NPs在种植体领域的安全应用提供理论依据。     

纳米二氧化钛在生物医学中的应用进展

纳米二氧化钛(nano-sized dioxide titanium,nano-TiO2)具有较大的比表面积、优良的光催化性能,是目前世界上使用最多的纳米材料之一。纳米技术的快速发展使得纳米二氧化钛在生物医学领域也得到了广泛的关注和应用,该文综述了纳米TiO2在肿瘤治疗、种植体表面改性、抗菌方面的应用及其可能的不良反应。     

牙科纳米氧化锆陶瓷粉体的制备

目的 :探讨用于增韧牙科氧化铝陶瓷的纳米氧化锆陶瓷粉体的制备方法。方法 :应用沉淀法 ,比较不同前驱物浓度和 pH值等条件下 ,所制备氧化锆粉体的物理性能。 结果 :ZrOCl2 ·8H2 O浓度为 0 .3～ 0 .5mol/L、pH 8.5时 ,经 70 0℃煅烧 2h后 ,可获得性能优良、粒径约为 10 0nm的氧化锆陶瓷粉体。 结论 :选择适当的条件 ,该方法可制得粒径小、团聚少的纳米氧化锆陶瓷粉体。     

牙科纳米氧化铝复合树脂的制备与性能研究

目的 制备一种新型的光固化纳米氧化铝复合树脂,探讨其用于口腔临床的可行性。方法 以双酚A双甲基丙烯酸缩水甘油酯(Bis-GMA)为树脂基质,甲基丙烯酸羟乙酯(HEMA)为活性稀释剂,添加纳米氧化铝填料对树脂基质进行增强增韧改性,制备一种新型牙科纳米氧化铝复合树脂,并表征其固化程度、弯曲强度、硬度、断面形貌、耐磨性、吸水性与水溶解性。结果 添加纳米氧化铝能提高复合树脂材料的刚性和硬度,当添加量达到3wt%时,复合树脂的力学性能、吸水和溶解性能均为最优。结论 复合树脂中加入一定比例的纳米氧化铝可达到增韧和耐磨的效果,该研究为开发新型牙科复合树脂提供了理论和实验基础。     

纳米二氧化钛对正畸粘接剂抗菌性与拉伸粘接强度的影响

目的研究纳米级二氧化钛对正畸托槽粘接剂抗菌效果及拉伸粘接强度的影响。方法在光固化托槽粘接剂(Grengloo)中加入质量分数1%、2%、3%纳米级二氧化钛。空白对照组不加入二氧化钛。将托槽粘接于离体前磨牙上,测量拉伸粘接强度与粘接剂残留量。粘接剂制成树脂圆片与菌悬液共培养48 h后,进行细菌活性与代谢测定。结果 4组粘接剂的拉伸粘接强度和粘接剂残留指数无显著差异。2%、3%组的pH值明显增加、乳酸产生量明显减少,但两组间无明显差别。加入纳米二氧化钛的三组菌落计数均明显减少,但3组间无明显差别。结论 2%纳米二氧化钛对Grengloo托槽粘接剂拉伸粘接强度无明显影响,同时提高其抗菌性。     

硅橡胶中纳米二氧化钛对白色念珠菌生长影响的初探

目的 通过研究纳米二氧化钛对硅橡胶体外抗白色念珠菌性能的影响,探讨用纳米二氧化钛改善硅橡胶抗白色念珠菌性能的可靠性.方法 硅橡胶中加入质量分数分别为0.5%、1.0%、1.5%、2.0%的纳米二氧化钛抗菌剂,分别记为A、B、C、D组,对照组硅橡胶不加纳米二氧化钛,采用薄膜密着法在光照和无光照条件下测定各组硅橡胶对白色念珠菌的抗菌作用.结果 光照条件下,A、B、C、D组菌落数[分别为(439.0±21.9)CFU、(289.3±7.8)CFU、(173.0±7.6)CFU、(86.7±3.9)CFU]与对照组[(597.3±5.5)CFU]的差异均有统计学意义(P<0.05);非光照条件下,A、B、C、D组菌落数[分别为(543.7±22.8)CFU、(478.0±17.0)CFU、(422.7±21.8)CFU、(283.0±12.1)CFU]与对照组[(611.3±10.0)CFU]的差异均有统计学意义(P<0.05).D组抗菌性能最好,无光照条件下,抑菌率为53.7%;光照条件下,抑菌率可达85.9%.结论 添加了纳米二氧化钛抗菌剂的硅橡胶在光照和无光照条件下均能抑制白色念珠菌生长,随着纳米二氧化钛质量分数的增加,硅橡胶抑菌效果增强.纳米二氧化钛质量分数相同时,光照下硅橡胶的抑菌性比无光照强.     

Preparation and characterization of TiO2-NTs/SnO2-Sb electrodes by electrodeposition

The novel Sb-doped SnO₂ electrodes (TiO₂-NTs/SnO₂-Sb) have been prepared by anodization, electrodeposition and annealing. TiO₂ nanotubes (TiO₂-NTs) after Sb and Sn electrodeposited were characterized using field-emission scanning electron microscopy (FE-SEM). In contrast with the traditional Sb-doped SnO₂ coating prepared by thermal decomposition, the Sb-doped SnO₂ coating prepared by electrodeposition processes show more compact. X-ray diffraction (XRD) analysis indicates that the Sb-doped SnO₂ coating prepared by electrodeposition processes are firmly combined with the TiO₂-NTs formed on the Ti substrate. Accelerated service life tests reveal that the electrodeposition processes enhance the electrochemical stability of the Sb-doped SnO₂ electrode. The cyclic voltammetry analysis shows that TiO₂-NTs/SnO₂-Sb electrodes have higher overpotential for oxygen evolution and higher electrochemical porosity. Besides, the enhanced stabilization mechanism of the TiO₂-NTs/SnO₂-Sb electrode prepared by electrodeposition processes has been studied.     

Biomechanical properties of nano-TiO2 addition to a medical silicone elastomer: The effect of artificial ageing

Objectives

The aim of this study was to evaluate the effect of TiO₂ nanoparticles on the mechanical and anti-ageing properties of a medical silicone elastomer and to assess the biocompatibility of this novel combination.

Methods

TiO₂ (P25, Degussa, Germany) nanoparticles were mixed with the silicone elastomer (MDX4-4210, Dow Corning, USA) at 2%, 4%, and 6% (w/w) using silicone fluid as diluent (Q7-9180, Dow Corning, USA). Blank silicone elastomer served as the control material. The physical properties and biocompatibility of the composites were examined. The tensile strength was tested for 0% and 6% (w/w) before and after artificial ageing. SEM analysis was performed.

Results

TiO₂ nanoparticles improved the tensile strength and Shore A hardness of the silicone elastomer (P < 0.05). However, a decrease in the elongation at break and tear strength was found for the 6% (w/w) composite (P < 0.05). All the ageing methods had no effect on the tensile strength of the 6% (w/w) composite (P > 0.05), but thermal ageing significantly decreased the tensile strength of the control group (P < 0.05). Cellular viability assays indicated that the composite exhibited biocompatibility.

Conclusions

We obtained a promising restorative material which yields favourable physical and anti-ageing properties and is biocompatible in our in vitro cellular studies.     

The effect of doping Mg on the structure and electrochemical properties of Li3V2(PO4)3 cathode materials for lithium-ion batteries

The Mg-doped Li₃V_2−xMg_x(PO₄)₃ (x = 0.00, 0.01, 0.02, 0.05, 0.10, 0.20, 0.30, 0.33, 0.50, 1.00 and 1.33) compounds have been prepared by a sol–gel method in reducing atmosphere (70%Ar + 30%H₂) using citric acid as a chelating agent and a carbon source coated on the samples. The Mg-doped effects on the structural and electrochemical performance of Li₃V₂(PO₄)₃ are investigated by X-ray diffraction, galvanostatic, charge/discharge and four-point probe measurement method. The Li₃V_2−xMg_x(PO₄)₃ solid solution phase can exist stable in the composition range between x = 0.00 and 0.27. The simple improve mechanism of the electrochemical performance for Mg-doped Li₃V_2−xMg_x(PO₄)₃ system is discussed too. In the Mg-doped Li₃V_2−xMg_x(PO₄)₃ system, at a lower charge/discharge rate (0.1C), the cycle performance has no much improvement with the increasing Mg doping content. However, at higher rates, there has an excited improvement in both cycle performance and rate capability due to the increase of electrical conductivity (more than one order of magnitude). At 5C charge/discharge rate, for the Li₃V_1.95Mg_0.05(PO₄)₃ sample, the discharge capacities for the 1st and 100th cycle were 138.9 and 123.3 mAh g⁻¹. The discharge capacity retention reached to 89% (more than 51% for undoped Li₃V₂(PO₄)₃ system). More important is that, except for the first 15 cycles, the discharge capacities kept almost a constant. Based on the excellent electrochemical performance, Li₃V_1.95Mg_0.05(PO₄)₃ will be a promising cathode material for rechargeable lithium-ion batteries.     

Electrocatalytic oxidation and reduction of H2O2 on vertically aligned Co3O4 nanowalls electrode: Toward H2O2 detection

Single crystal and vertically aligned cobalt oxide (Co₃O₄) nanowalls were synthesized by directly heating Co foil on a hot-plate under ambient conditions. The vertically aligned Co₃O₄ nanowalls grown on the plate show excellent mechanical property and were facilely attached to the surface of a glassy carbon (GC) electrode using conductive silver paint. The prepared Co₃O₄ nanowalls electrode was then applied to study the electrocatalytic oxidation and reduction of hydrogen peroxide (H₂O₂) in 0.01 M pH 7.4 phosphate buffer medium. Upon the addition of H₂O₂, the Co₃O₄ nanowalls electrode exhibits significant oxidation and reduction of H₂O₂ starting around +0.25 V (vs. Ag/AgCl), while no obvious redox activity is observed at a bare GC electrode over most of the potential range. The superior electrocatalytic response to H₂O₂ is mainly attributed to the large surface area, minimized diffusion resistance, high surface energy, and enhanced electron transfer of the as-synthesized Co₃O₄ nanowalls. The same Co₃O₄ nanowalls electrode was also applied for the amperometric detection of H₂O₂ and showed a fast response and high sensitivity at applied potentials of +0.8 V and −0.2 V (vs. Ag/AgCl), respectively. The results also demonstrate that Co₃O₄ nanowalls have great potential in sensor and biosensor applications.     

Microwave assisted chemical bath deposition of CdS on TiO2 film for quantum dot-sensitized solar cells

A simple, rapid and effective method of microwave assisted chemical bath deposition (MACBD) has been used to deposit CdS quantum dots on the surface of TiO₂ film as photoanode of quantum dot-sensitized solar cells. The photovoltaic performance of the as-prepared cell is investigated. The results show that the cell based on MACBD deposited TiO₂/CdS electrode achieves an improved short circuit current density of 6.69 mA cm⁻² and power conversion efficiency of 1.03% at one sun (AM 1.5G, 100 mW cm⁻²) as compared with the one employing conventional sequential chemical bath deposition method.     

不同浓度的过氧化氢对银汞合金表面性能的影响

目的研究不同浓度过氧化氢对银汞合金表面性能的影响。方法采用表面轮廓仪和扫描电镜对0 wt%、3.6 wt%、10 wt%和30 wt%四种浓度过氧化氢浸泡112 h后的牙科银汞合金的表面粗糙度、表面形貌进行比较,并运用光电子能谱仪分析0%和30%两种浓度过氧化氢浸泡后银汞合金的表面腐蚀产物。结果过氧化氢浸泡112 h后,不同银汞合金表面粗糙度的Ra和Rz的大小顺序均为0 wt%<3.6 wt%<10 wt%<30 wt%;且表面均有不同程度的腐蚀,主要表现为分布不均匀、孔径大小不一的点蚀,其中以30wt%过氧化氢浸泡组的腐蚀最明显;此外,0 wt%和30 wt%过氧化氢浸泡后,银汞合金表面分别检测到Cu、Sn、Hg、Ag、O元素,表面氧化物主要为SnO₂,与0 wt%过氧化氢相比,30 wt%过氧化氢浸泡后,银汞合金表面Ag、Hg、O元素含量明显下降,而Sn、Cu元素含量则升高。结论随着过氧化氢浓度的升高,银汞合金表面粗糙度增加,表面形貌有不同程度腐蚀,表面腐蚀产物成分有所改变,氧化程度减弱。     

EQCM study of electrochemical modification of Bi2S3 films in the Zn-containing electrolyte

The electrochemical behavior of Bi₂S₃ as-deposited on Au using the successive ionic layer adsorption and reaction method has been investigated in the Zn²⁺-free background and Zn²⁺-containing electrolytes at different pH by electrochemical quartz crystal microbalance coupled with cyclic voltammetry and X-ray photoelectron spectroscopy. It has been shown that when the Bi₂S₃ film is reduced in the Zn²⁺-containing electrolyte Zn²⁺ ions are involved in electrochemical bismuth sulfide reduction and are partially reduced together with the bismuth sulfide film. The bismuth sulfide film initiates the adsorbed Zn²⁺ ions reduction prior to the traditional overpotential deposition of it. Reduction of Zn²⁺ ions prior to the overpotential deposition of Zn depends on solution pH: at pH 5 it occurs at more negative potential values and the observed mass changes due to Zn electrodeposition are greater than at solution pH 3. After bismuth sulfide film reduction in the Zn²⁺-containing electrolyte, Zn was detected as ZnO and metallic Zn at pH 5, while at pH 3 only ZnO was detected.