纳米TiO2-免疫-电生孔复合技术光催化氧化杀伤LoVo肠癌细胞的机理

纳米TiO2光催化氧化·免疫.电生孔复合技术能够在低的纳米TiO2浓度条件下(3.12 μg·mL-1)高效选择性地杀伤LoVo肠癌细胞.在光强为4 mW·cm-2的紫外光(波长253.7 nm)照射下,30 min内可全部杀死癌细胞.利用共聚焦荧光显微镜、透射电镜(TEM)和单细胞凝胶电泳的方法研究了其作用过程.结果表明,经抗体修饰的纳米TiO2微粒能自动吸附在癌细胞的细胞膜上,在电脉冲作用下纳米TiO2可进入细胞内部,并主要集中在细胞核区域.在紫外光的照射下,基于纳米TiO2的光催化氧化作用,造成细胞内一些细胞器、核膜和核中DNA的损伤,使细胞坏死.由于是在细胞内部产生光催化氧化作用,显著提高了杀伤LoVo肠癌细胞的能力.     

结合电生孔技术的抗体-纳米TiO2靶向光敏杀癌细胞

报道了用免疫、电生孔和纳米TiO₂光催化组合技术进行杀伤结肠癌LoVo细胞的研究. 先把结合LoVo细胞表面CEA抗原的单克隆抗CEA抗体吸附在纳米TiO₂微粒表面, 抗体-纳米TiO₂复合微粒就会自动吸附到LoVo细胞的表面, 然后用电脉冲法使LoVo癌细胞的细胞膜上产生小孔, 促使纳米TiO₂微粒进入癌细胞内部. 最后在紫外光照射下使TiO₂纳米粒子在癌细胞内部发生光催化氧化作用, 杀伤癌细胞. 结果表明, 这种组合技术具有很高的杀癌细胞能力. 在仅含3.12 μg/mL抗体-纳米TiO₂的细胞培养液内和强度为4 mW/cm²的紫外光照射下, 可在30 min内将所有LoVo癌细胞杀死. 这种技术对LoVo癌细胞的杀伤力远高于对不表达CEA抗原的人正常TE353.sk细胞的杀伤力, 显示了组合技术杀癌细胞的高选择性. 因此, 这种组合技术有望成为治疗癌症的新方法, 值得进一步探索.     

结合电生孔技术的抗体-纳米TiO2靶向光敏杀癌细胞

报道了用免疫、电生孔和纳米TiO₂光催化组合技术进行杀伤结肠癌LoVo细胞的研究. 先把结合LoVo细胞表面CEA抗原的单克隆抗CEA抗体吸附在纳米TiO₂微粒表面, 抗体-纳米TiO₂复合微粒就会自动吸附到LoVo细胞的表面, 然后用电脉冲法使LoVo癌细胞的细胞膜上产生小孔, 促使纳米TiO₂微粒进入癌细胞内部. 最后在紫外光照射下使TiO₂纳米粒子在癌细胞内部发生光催化氧化作用, 杀伤癌细胞. 结果表明, 这种组合技术具有很高的杀癌细胞能力. 在仅含3.12 μg/mL抗体-纳米TiO₂的细胞培养液内和强度为4 mW/cm²的紫外光照射下, 可在30 min内将所有LoVo癌细胞杀死. 这种技术对LoVo癌细胞的杀伤力远高于对不表达CEA抗原的人正常TE353.sk细胞的杀伤力, 显示了组合技术杀癌细胞的高选择性. 因此, 这种组合技术有望成为治疗癌症的新方法, 值得进一步探索.     

Au改性TiO2纳米复合物对人结肠癌细胞的光催化杀伤作用

提出了通过TiO₂表面修饰纳米Au的方法来提高纳米TiO₂光催化杀伤癌细胞的效率. 采用化学还原法合成了Au改性的TiO₂ (Au/TiO₂)纳米复合物, 并研究了不同掺杂量(1 wt%, 2 wt%, 4 wt%)的Au/TiO₂对人结肠癌LoVo细胞的光催化杀伤效应. 结果显示, Au的掺杂大大地提高了TiO₂纳米粒子光催化杀伤结肠癌LoVo细胞的效率, 而且Au掺杂量的高低影响Au/TiO₂光催化杀伤癌细胞的效率, 掺金量为2%的Au/TiO₂对结肠癌LoVo细胞具有最高的光催化杀伤效率. 在光强为1.8 mW/cm²的紫外灯(λ_max＝365 nm)下光照110 min, 50 μg/mL掺金量为2%的Au/TiO₂能够杀死所有的癌细胞, 而同样浓度的TiO₂只能杀死70%的癌细胞.     

纳米Fe_3O_4-TiO_2靶向光动力疗法对肝癌细胞的杀伤效应（英文）

光动力疗法(PDT)作为一种迅速发展的传统替代疗法,在抗癌治疗中显示出巨大的潜力。为增强靶向性和提高光催化杀伤效率,本研究设计了一种新型光敏剂Fe_3O_4-Ti O_2磁性纳米粒。在不同外磁场下,考察其在可见光和紫外光激发下对肝癌细胞的杀伤效应。同时利用流式细胞术检测纳米Fe_3O_4-Ti O_2对肝癌细胞凋亡率、细胞周期和线粒体膜电位的影响。根据纳米Fe_3O_4-Ti O_2和肝癌细胞的作用方式探讨其抗癌机制。结果表明,可见光激发纳米Fe_3O_4-Ti O_2可以杀伤癌细胞,且其杀伤效率与紫外光激发下无明显差别。此外,Fe_3O_4-Ti O_2比Ti O_2具有更高的细胞摄取率,从而使其具有更高的选择性和光催化杀伤效率。其作用机制是光催化纳米Fe_3O_4-Ti O_2产生活性氧ROS抑制癌细胞,然后通过阻滞细胞周期G_0/G_1期,降低线粒体膜电位,线粒体去极化,最终诱导细胞凋亡。     

纳米TiO2对胃癌细胞的光催化氧化杀伤效应

纳米TiO2对胃癌细胞的光催化氧化杀伤效应;胃癌细胞(BGC-823);抗癌剂     

Ag修饰的Fe_3O_4/TiO_2复合磁性纳米纤维的制备及光催化性能

通过静电纺丝法制备了含有Fe3O4纳米粒子的TiO2纳米纤维,采用水热法对该纤维表面进行纳米Ag修饰,制备出具有较强磁性和较好光催化性能的复合纤维.采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和紫外-可见光谱(UV-Vis)等对样品的结构和形貌进行表征,并以罗丹明B(Rh B)水溶液降解为模型反应,考察样品在紫外光照射下的光催化性能.结果表明,所制备的TiO2为锐钛矿结构,Fe3O4纳米粒子均匀分布在TiO2纤维中,Ag纳米颗粒比较均匀地分散在磁性TiO2纤维表面.经过纳米Ag修饰后,材料的光吸收能力大为增强,吸收带红移并扩展到可见光区.在紫外光照射40 min后,合成样品对Rh B的降解率达到99.5%.此外,Fe3O4纳米粒子的存在使该材料具有较强的磁性,可通过外加磁场将其分离回收.     

低量镱掺杂TiO2纳米光催化剂的溶胶-溶剂热制备及光活性

利用溶胶-溶剂热技术制备了锐钛矿型Yb掺杂和未掺杂TiO2纳米粒子,以亚甲基蓝(MB)溶液在紫外光和可见光照射下的光催化脱色率评价其光活性,考察了溶剂热温度、Yb掺杂量和焙烧温度对样品光活性的影响;结合XRD,BET,XPS,FT-IR,DRS和PL表征手段,探讨了Yb掺杂对TiO2光活性的影响机制.结果表明,低量Yb掺杂不仅显著提高TiO2的紫外光活性,也明显提高其可见光活性.Yb掺杂调整TiO2带隙内部电子分布状态,有效抑制光生e-/h+复合,提高量子效率;并且增加表面羟基,增大比表面积,改善表面织构特性,致使紫外光活性提高.然而Yb掺杂并未引起紫外吸收带边红移,其可见光活性的提高应归因于Yb掺杂强化了表面吸附染料的敏化作用.     

一步低温法制备可见光响应的棕色纳米TiO2及其光催化性能

光催化作为一种具有前景的技术,被广泛运用于有机物降解、废水处理、空气净化、抗菌、太阳能电池等领域.在众多的光催化材料中,纳米TiO2因具有性质稳定、耐腐蚀、廉价和无毒等优点而受到广泛关注.但纳米TiO2禁带宽度较大(3.2 eV)、只对紫外光有响应及电子-空穴对易复合等特性限制了它的应用.因此,提高纳米TiO2的可见光响应一直是研究的热点.本文发展了一种在低温下制备棕色纳米TiO2的改良溶胶-凝胶法.该法以钛酸四丁酯为钛源,无水乙醇为溶剂,形成溶胶后无需陈化和高温高压,在简单温和的条件下即可制备出棕色纳米TiO2.比较了低温干燥和高温焙烧两种处理方法,结果表明,随着制备温度的升高,样品的粒子尺寸增大,比表面积减小,颜色从白色转变为棕色,在更高的温度又变浅.样品的可见光吸收在180℃时达到最大,随后减弱.在优化温度180℃下制备的TiO2-180℃纳米粒子不仅具有较小的粒径(5.0 nm),较大的比表面积(213.45 m2/g),且在整个紫外-可见光区都具有较强的吸收,其禁带宽度低至1.84 eV.X-射线光电子能谱结果表明,TiO2粒子表面的–OH/H2O含量随制备温度升高而先增加后下降.Raman光谱中Eg峰的移动和变宽表明TiO2晶格可能存在缺陷或氧空位,而TiO2-180℃纳米粒子的电子顺磁共振图谱的g值在2.003左右,对应氧空位中的未成对电子,验证了以上推测.其中TiO2-180℃纳米粒子呈现为最强的EPR信号,表明其晶格内存在最高浓度的氧空位,这是其具有强可见光吸收的原因.光催化实验结果表明,在可见光照射下,TiO2-180℃可高效降解亚甲基蓝(MB).当C(MB)=10 mg/L,pH=4,催化剂添加量为0.07 g时,TiO2-180℃催化剂的光催化活性达到最佳,光照1 h后MB降解率达到99.33%,反应速率常数(0.08287 mg/(L·min))约为同条件下P25(0.01342 mg/(L·min))的6倍.同时,TiO2-180℃催化剂在不同单色光下的光催化活性与它对单色光的光响应大致相符.循环降解实验证明TiO2-180℃催化剂具有很好的稳定性.光猝灭实验表明,·OH在光催化降解过程占主导作用,而TiO2-180℃样品表面含有较多的–OH,有利于·OH的产生,乃至光催化反应.研究表明,晶格内高浓度的氧空位导致的强可见光响应,得益于低温制备条件而保留了大量–OH/H2O的纳米粒子表面以及更大的比表面积,共同促成了TiO2-180℃优越的光催化活性.所制备的棕色纳米TiO2经过进一步修饰后有望运用于实际应用中.     

碳纳米管负载纳米TiO2复合材料的制备及其性能

采用溶胶-凝胶法, 以钛酸丁酯为原料, 将纳米TiO2负载在碳纳米管(CNTs)表面, 制备了CNT-TiO2光催化复合材料. 通过X射线衍射(XRD)、透射电子显微镜(TEM)等手段研究了复合颗粒的形态结构及包覆情况, 通过UV-Vis漫反射谱分析比较了纯TiO2和CNT-TiO2的吸光性能, 并研究了不同温度热处理的CNT-TiO2光催化剂在紫外光照射下对甲基橙光催化降解的性能. 结果表明, 纳米TiO2颗粒以锐钛矿相存在, 紧密地包附在碳纳米管的管壁上, CNT-TiO2在紫外-可见光波长范围内均有较好的吸光性能, 450 ℃热处理后的复合光催化剂CNT-TiO2比纯TiO2对甲基橙光降解有更高的光催化活性.     

Photokilling cancer cells using highly cell-specific antibody-TiO(2) bioconjugates and electroporation

In this paper, it was reported for the first time that the combination of the electroporation and the conjugation of the TiO(2) nanoparticles with the monoclonal antibody could improve the photokilling selectivity and efficiency of photoexcited TiO(2) on cancer cells in the photodynamic therapy(PDT) because the conjugation of the TiO(2) nanoparticles with monoclonal antibodies could increase the photokilling selectivity of TiO(2) nanoparticles to cancer cells and the electroporation could accelerate the delivery speed of the TiO(2) nanoparticles to cancer cells. It was observed that using this combination method, 100% human LoVo cancer cells were photokilled within 90 min, while only 39% of the normal cells were killed under the irradiation of the ultraviolet (UV) light (365 nm). Furthermore, the combination method may be used to photokill various kinds of caner cells only if the antibody conjugated on the TiO(2) nanoparticles is changed.     

Photokilling Squamous Carcinoma Cells SCCVII with Ultrafine Particles of Selected Metal Oxides

The ability of ultrafine particles of TiO₂, WO₃ and iron-doped TiO₂ to kill cancer cells in the presence of UV irradiation was investigated. The best photokilling effect on carcinoma cells SCVII cultured in vitro showed iron-doped TiO₂ ultrafine particles synthesized by the sol-gel procedure with starting chemicals Ti(IV)-isopropoxide and anhydrous Fe(II)-acetate. It was found that a small particle size and high dispersity influenced citotoxicity and photocatalytic efficiency. The remarkable photokiling effect of highly iron-doped TiO₂ ultrafine particles (the molar ratio Fe/Ti = 0.136) in the presence of UV irradiation was observed. The influence of ultrafine metal oxide particles on the inhibition of cancer cell proliferation was measured using a ³H-thymidine incorporation test. The possible mechanism involved in the photokilling of carcinoma cells with ultrafine particles of selected metal oxides was discussed.     

金属离子掺杂二氧化钛及水体光催化脱氮研究

采用溶胶-凝胶法制备了掺杂Ce³⁺、La³⁺、Ag⁺、Fe³⁺的TiO₂光催化剂,以考察其薄膜和粉体形式对水中无机氮的光催化去除效果和活性.用所制备的催化剂对含氨氮-亚硝酸氮的混合液进行了光催化脱氮研究.本文利用UV-Vis吸收光谱、XRD和TEM对催化剂进行了表征.同时,对影响TiO₂光催化效率的因素:如掺杂金属离子的种类、浓度、涂膜层数、反应液中有无Fe²⁺、不锈钢和玻璃载体、反应器的构型等进行了探讨,并对今后的研究进行展望.经过2 h紫外光照射反应,实验最佳脱氮效果:金属离子掺杂TiO₂薄膜型催化剂总氮去除率在30%左右,金属离子掺杂粉末型催化剂光催化最高总氮去除率可达41.7%.     

Ag/AgBr/TiO2 visible light photocatalyst for destruction of azodyes and bacteria

Ag/AgBr/TiO2 was prepared by the deposition-precipitation method and was found to be a novel visible light driven photocatalyst. The catalyst showed high efficiency for the degradation of nonbiodegradable azodyes and the killing of Escherichia coli under visible light irradiation (lambda>420 nm). The catalyst activity was maintained effectively after successive cyclic experiments under UV or visible light irradiation without the destruction of AgBr. On the basis of the characterization of X-ray diffraction, X-ray photoelectron spectroscopy, and Auger electron spectroscopy, the surface Ag species mainly exist as Ag0 in the structure of all samples before and after reaction, and Ag0 species scavenged hVB+ and then trapped eCB- in the process of photocatalytic reaction, inhibiting the decomposition of AgBr. The studies of ESR and H2O2 formation revealed that *OH and O2*- were formed in visible light irradiated aqueous Ag/AgBr/TiO2 suspension, while there was no reactive oxygen species in the visible light irradiated Ag0/TiO2 system. The results indicate that AgBr is the main photoactive species for the destruction of azodyes and bacteria under visible light. In addition, the bactericidal efficiency and killing mechanism of Ag/AgBr/TiO2 under visible light irradiation are illustrated and discussed.     

Mechanism of photoinduced superhydrophilicity on the TiO2 photocatalyst surface

The physicochemical properties of the H(2)O molecules adsorbed on TiO(2) surfaces during UV light irradiation were fully investigated by near-infrared (NIR) absorption spectroscopy. It was found that the H(2)O molecules adsorbed on the TiO(2) surfaces desorb during UV light irradiation by the heating effect of the light source. Since the amount of the H(2)O adsorbed on the TiO(2) surfaces decreased, the distribution of the hydrogen bonds within the H(2)O molecules decreased, resulting in a decrease in the surface tension of the H(2)O clusters. The decrease in the surface tension of H(2)O under UV light irradiation was found to be one of the most important driving forces in which the H(2)O clusters on the TiO(2) surface spread out thermodynamically, forming H(2)O thin layers. The partial elimination of the hydrocarbons from the TiO(2) surface by the photocatalytic complete oxidation was seen to be the other important factor, providing free spaces on the surface where the H(2)O clusters could spill over and spread out to form the thin H(2)O layers. Moreover, the temperature changes of the TiO(2) powder samples during UV light irradiation were found to show a good correspondence with the changes in the contact angle of the H(2)O droplets on the TiO(2) thin film surfaces. Especially the time scale for the hydrophilic conversion on the TiO(2) surfaces under UV light irradiation was in good agreement with the decrease in the amount of H(2)O molecules adsorbed on the TiO(2) surfaces but not the amount of the hydrocarbons eliminated by the photocatalytic oxidation reactions, showing that the adsorption and desorption of H(2)O molecules are generally quite sensitive to the temperature changes of solid surfaces.     

超声波辐射快速合成高光催化性能的BiOCl(Br)纳米片

在室温条件下,利用超声波辐射方法快速合成了四方状BiOCl(BiOBr)纳米片光催化剂。应用N2-物理吸附、X射线粉末衍射、扫描电镜、透射电镜、紫外可见光谱等手段对催化剂进行了表征,并以波长为λ=365 nm的紫外光和420 nm<λ<660 nm的可见光为光源,评价了该催化剂光催化降解酸性橙Ⅱ的活性。表征结果表明,超声波辐射可加速BiOCl和BiOBr晶化过程,显著提高BiOCl和BiOBr的结晶度,并使其晶粒发生细化,提高催化剂的比表面积。活性测试表明,声化学合成样品的光催化活性优于普通搅拌制备的样品。其中BiOCl的紫外光催化活性高于商业TiO2(P25)光催化剂。     

Photodeposition of Ag2S quantum dots and application to photoelectrochemical cells for hydrogen production under simulated sunlight

UV light irradiation of TiO(2) (λ > 320 nm) in a mixed solution of AgNO(3) and S(8) has led to the formation of Ag(2)S quantum dots (QDs) on TiO(2), while Ag nanoparticles (NPs) are photodeposited without S(8). Photoelectrochemical measurements indicated that the Ag(2)S photodeposition proceeds via the preferential reduction of Ag(+) ions to Ag(0), followed by the chemical reaction with S(8). The application of this in situ photodeposition technique to mesoporous (mp) TiO(2) nanocrystalline films coated on fluorine-doped SnO(2) (FTO) electrodes enables formation of Ag(2)S QDs (Ag(2)S/mp-TiO(2)/FTO). Ag(2)S/mp-TiO(2)/FTO has the interband transition absorption in the whole visible region, while in the spectrum of Ag/mp-TiO(2)/FTO, a localized surface plasmon resonance absorption of Ag NPs is present centered at 490 nm. Ag(2)S QD-sensitized photoelectrochemical cells using the Ag(2)S/mp-TiO(2)/FTO and Ag/mp-TiO(2)/FTO photoanodes were fabricated. Under illumination of one sun, the Ag(2)S photoanode cell yielded H(2) at a rate of 0.8 mL·h(-1) with a total conversion efficiency of 0.29%, whereas the Ag/mp-TiO(2)/FTO photoanode is inactive.     

真空离子溅射法制备TiO2∶Au复合纳米纤维新型光催化剂及其 降解乙醛性能研究

采用静电纺丝技术与真空离子溅射相结合的方法制备了TiO2∶Au复合纳米纤维, 并采用SEM和X射线电子能谱仪对其进行了表征. 结果表明TiO2∶Au纳米纤维的表面形态能通过Au沉积时间得到很好的控制. 同时在紫外光照射下采用乙醛体系考察了TiO2纳米纤维和TiO2∶Au复合纳米纤维催化剂降解乙醛性能, 结果证明TiO2∶Au复合纳米纤维具有更好的催化效率, 紫外光照射70 min后乙醛被完全降解.