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Fe3O4-TiO2靶向光动力疗法对肝癌细胞的杀伤效应

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Fe₃O₄-TiO₂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Fe₃O₄-TiO₂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Fe₃O₄-TiO₂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Fe₃O₄-TiO₂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,Fe₃O₄-TiO₂比TiO₂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Fe₃O₄-TiO₂产生活性氧ROS抑制癌细胞,然后通过阻滞细胞周期G₀/G₁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-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.     

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.     

TiO2/Gd2O3纳米粉体的制备、表征及光催化活性

利用酸催化的溶胶-凝胶法制备了纯TiO₂和Gd³⁺(0.5wt%)掺杂的TiO₂纳米粉体，采用XRD、BET、XPS、紫外-可见漫反射谱(DRS)和表面光电压谱(SPS)等技术进行了表征；以亚甲基蓝(MB)的光催化降解为探针反应，评价了其光催化活性；探讨了Gd³⁺掺杂对TiO₂纳米粉体的光催化活性的影响机制。结果表明，TiO₂/Gd₂O₃纳米粒子对MB溶液的光催化活性提高到纯TiO₂的1.5倍。掺杂Gd³⁺可以强烈抑制TiO₂由锐钛矿相向金红石相的转变；阻碍TiO₂晶粒的生长；提高高温组织稳定性，改善粉体的表面织构特性；形成光生电子的浅势捕获陷阱，抑制e^-/h⁺复合，这些因素共同作用最终导致TiO₂/Gd₂O₃纳米粉体的光催化活性明显提高。XPS分析结果证实，掺杂Gd³⁺导致粉体的表面羟基含量降低。由于产生了量子尺寸效应，复合粉体的紫外吸收带边蓝移，光的吸收能力略有降低。     

Ce掺杂Bi2MoO6/TiO2纳米纤维异质结的制备及可见光催化性能

以静电纺丝技术制备的TiO₂纳米纤维为基质,通过溶剂热法制备了异质结型稀土Ce掺杂Bi₂MoO₆/TiO₂复合纳米纤维。利用X射线衍射（XRD）、扫描电子显微镜（SEM）、X射线光电子能谱（XPS）、透射电镜（TEM）、紫外-可见漫反射光谱（UV-Vis DRS）以及荧光光谱（PL）等分析测试手段对样品的物相、形貌和光学性能等进行表征。以罗丹明B为模拟有机污染物,研究了样品的可见光催化性能。结果表明：在稀土掺杂样品中,Ce离子进入Bi₂MoO₆晶格,部分取代Bi³⁺,导致晶胞膨胀,晶格畸变,形成缺陷;与TiO₂复合形成异质结,有利于光生电荷的产生、转移和有效分离,从而提高TiO₂纳米纤维的光催化活性。可见光照射180 min,罗丹明B的降解率达到95.1%。经5次循环光催化降解活性基本不变,样品具有良好的光催化稳定性。     

阳极氧化法制备TiO2纳米管及其光催化性能

纳米TiO₂对诸多环境污染物有显著的光催化降解作用,光催化已发展成为新型环境污染治理技术。本文采用阳极氧化法制备出TiO₂纳米管,对比了四种电解液组成(A氟化铵+硫酸铵+水;B氟化铵+硫酸铵+乙酸+水;C氟化铵+硫酸铵+甘油+水;D氢氟酸+二甲基亚砜(DMOS)+乙醇)对催化剂表面形貌及光催化性能的影响。结果表明,电解液A和C都制备出了形貌清晰的TiO₂纳米管,管径约为60~74 nm。样品经400 ℃煅烧,TiO₂晶型主要为锐钛矿相;经500 ℃煅烧,出现少量金红石相;经700 ℃煅烧,晶型全部为金红石相。具有良好形貌的TiO₂纳米管同时具有良好的紫外光吸收能力。当亚甲基蓝初始浓度为10 mg·L^-1,经500 ℃煅烧的TiO₂纳米管光催化活性最佳,光照30 min亚甲基蓝的降解率达89.98%。亚甲基蓝光催化降解反应符合一级反应动力学,反应速率常数为0.079 30。     

纳米TiO2固相光催化降解固体废弃塑料

以纳米TiO₂作光催化剂,制备出环境友好的可光催化降解的纳米复合塑料是解决“白色污染”行之有效的方法之一。本文综述了近年来纳米TiO₂固相光催化降解固体废弃塑料的研究进展,探讨了TiO₂-聚合物复合膜的固相光催化反应机理及光催化降解情况,从对纳米TiO₂表面改性以改善其在聚合物中的分散性,对纳米TiO₂进行修饰处理以提高其对可见光的吸收,从而提高其光催化效率等方面探讨了可光降解塑料研究存在的问题及应用前景。     

Bi2WO6/TiO2纳米管异质结构复合材料的多模式下的光催化活性比较

以TiO₂纳米管为模板,采用多组分自组装结合水热法制备Bi₂WO₆/TiO₂纳米管异质结构复合材料。通过多种技术如X射线衍射（XRD）,X射线光电子能谱（XPS）,N₂吸附-脱附,扫描电镜（SEM）,高分辨透射电镜（HRTEM）和紫外可见漫反射吸收光谱（UV-Vis DRS）考察所制备样品的组成、结构、形貌、光吸收和电子性质。Bi₂WO₆纳米片或纳米粒子分布在TiO₂纳米管上,形成异质结构。随后,通过在紫外、可见和微波辅助光催化模式下降解染料罗丹明B（RhB）来评价复合催化剂的光催化活性。与TiO₂纳米管和Bi₂WO₆相比,Bi₂WO₆/TiO₂-35纳米管在多模式下表现出更优异的光催化活性。与紫外和可见降解模式相比,Bi₂WO₆/TiO₂-35纳米管在微波辅助光催化模式下对RhB的降解效率最高。这种增强的光催化活性源于适量Bi₂WO₆的引入、纳米管独特的形貌特征和降解模式所引起的增强的量子效率。降解过程中的活性物种被证明是h⁺,·OH和·O₂^-自由基。而且,在微波辅助光催化模式下,可产生更多的·OH和·O₂^-自由基。     

Photocatalytic Inactivation Efficiency of Anatase Nano-TiO2 Sol on the H9N2 Avian Influenza Virus

This study was conducted to investigate efficiency of TiO₂nanomaterial as a novel environment-friendly disinfectant to control avian influenza (AI) by its photochemical sterilization ability. Anatase nano-TiO₂sol, a neutral, viscous aqueous colloid of 1.6% TiO₂, was synthesized from peroxotitanic acid solution according to the Ichinose method. Transmission electron microscope images showed that the TiO₂particles were spindle-shaped with an average size of 50 nm. X-ray diffraction patterns revealed that the crystal phase of TiO₂particles was anatase type with photocatalytic effect. A photocatalytic film of nano-TiO₂sol was tested as a means of inactivating H₉N₂avian influenza virus (AIV). Inactivation capabilities were examined with 365 nm ultraviolet (UV) radiation under black light by adjusting the UV intensity, the UV irradiation time and the quantity of AIV. The titer change of AIV was determined by hemagglutination tests. Cytopathic effect of Madin Darby canine kidney (MDCK) cells was monitored by inverted fluorescence microscope. The results showed that anatase nano-TiO₂sol significantly inactivated AIV under UV irradiation of 365 nm. The inactivation of AIV viruses reached up to 100%. Therefore, anatase nano-TiO₂sol is a potentially environment-friendly antivirus agent to prevent AI.     

TiCl4 assisted formation of nano-TiO2 secondary structure in photoactive electrodes for high efficiency dye-sensitized solar cells

A new kind of photoactive electrodes with nanocrystalline TiO2(nano-TiO2)secondary structure is successfully prepared via a simple method of adding a small amount of TiCl4 2-propanol solution in conventional nano-TiO2 paste to form micro-sized nano-TiO2 aggregates.The benefits of this special structure include improved optical absorption,increased light scattering ability,and enhanced electron transport and collection efficiency.Dye-sensitized solar cells(DSCs)based on these photoactive electrodes show improved performance.The power conversion efficiency of the cells can be increased from 5.03%to 7.30%by substituting 6μm conventional nano-TiO2 thin film with the same thickness of as-prepared nano-TiO2 aggregates film in the photoactive electrodes.A higher power conversion efficiency of the cells can be obtained by further increasing the thickness of the nano-TiO2 aggregates film.     

改性二氧化钛纳米棒的制备及光催化有机污染物研究

为了改善纳米二氧化钛的光催化活性,通过水热法制备了氮钨共掺杂二氧化钛纳米棒。通过扫描电镜(SEM),X射线衍射(XRD),透射电镜(TEM),X射线光电子能谱(XPS)和紫外可见光吸收光谱 (UV-VIS)等对产物进行了相关表征。结果显示：与未掺杂的二氧化钛相比,氮钨共掺杂的二氧化钛纳米棒在可见光区域显示出了较强的光催化活性。因为氮钨阳离子的掺入拓宽了可见光的吸收区域。     

铁、铈共掺杂纳米TiO2溶胶的制备及抗菌性能

采用微波辅助胶溶工艺,在常压条件下,制备了可用于室内杀菌的铁、铈共掺杂纳米TiO₂水溶胶,通过X-射线衍射(XRD)、等离子体发射光谱(ICP)、动态光散射(DLS)、透射电镜(TEM)和X射线光电子能谱(XPS)对产物结构进行了表征,并选用白色葡萄球菌、大肠杆菌和枯草芽孢杆菌为受试菌种,分别在无光照、自然光照条件下,采用菌落计数法对水溶胶抗菌性能进行了检测。结果表明,用微波辅助胶溶工艺制备的Fe/Ce共掺杂纳米TiO₂为锐钛矿型,其平均粒径为10 nm。Fe/Ce的掺杂改性能有效提高纳米TiO₂水溶胶的抗菌性能,尤其是在自然光照条件下,Fe/Ce共掺杂纳米TiO₂溶胶在6 h内对各测试菌种的杀菌率均为95%以上,表明Fe/Ce共掺杂纳米TiO₂水溶胶具有很高的广谱杀菌性。采用透射电镜(TEM)对杀菌过程中的大肠杆菌菌体形态进行观测,探讨了Fe/Ce共掺杂纳米TiO₂水溶胶的抗菌机理。     

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.     

Reforming of Rice Ash Waste by Incorporated Nanotitania in Silica Framework for Photo-catalytic Treatment of Wastewater

The nano-composites based on the burnt rice straw waste, reformed by nano-TiO₂ and copper phthalocyanine (CuPc), namely, RSA-TiO₂, RSA-CuPc, and RSA-TiO₂-CuPc were prepared by a mechano-chemical method. The as-prepared composite systems were characterized by adopting FE-SEM, TEM, XRD, FTIR, SBET, and optical techniques. Their photo-catalytic performance in the degradation of methylene blue dye was evaluated under visible light irradiation. The co-existence of the two components in RSA, SiO₂ and organic carbon, plus the inherently intimate contact between nano-TiO₂ and CuPc could improve the photo-degradation of MB dye. The complete degradation of MB dye was achieved by using RSA-TiO₂ (50) nano-composite and the time is taken for 50% degradation of a dye is 53 min under visible light radiation. The kinetic study revealed that photo-degradation of MB follows a pseudo-first-order reaction mechanism, where the kinetic rate constant was 0.013 min⁻¹.     

Preparation and photocatalytic antibacterial property of nitrogen doped TiO2 nanoparticles

Nitrogen doped TiO₂ (N-TiO₂) nanoparticles with about 30 nm in size were produced by a sol–gel method and characterized respectively by UV–vis, X-ray diffraction (XRD), Transmission electron microscopy, X-ray photoelectron spectroscopy (XPS). Their photocatalytic antibacterial properties were evaluated by the antibacterial ratio against Escherichia coli in dark and under simulated sunlight respectively. The XRD pattern showed that the doped nano-TiO₂ was mainly composed of anatase phase. The XPS spectra of the N-TiO₂ sample indicated that TiO₂ was doped by nitrogen atom. The nitrogen doping created a new N 2p state slightly above the valence band top consists of O 2p state, and this pushes up the valence band top and decreased the band gap. Which leaded to the absorption edge was red-shifted to the visible light region of UV–vis spectra of nitrogen doped nano-TiO₂ comparing with pure nano-TiO₂. The antibacterial percentage of N-TiO₂ against E. coli reached to 90 % under simulated sunlight for 2 h, which was much better than that in dark, also than that of pure nano-TiO₂. The photo-catalytic antibacterial activity was activated under visible light. The structure and integrity of cell wall and cell membrane were destructed, and even caused the bacteria death.     

A study on the degradation of methamidophos in the presence of nano-TiO<Subscript>2</Subscript> catalyst doped with Re

A new Re-doped nano-TiO₂ photocatalyst was synthesized by immersion method. The novel doped nano-TiO₂ photocatalyst utilizing visible light was firstly prepared. The doped nano-TiO₂ powder was charactered by XRD, FTIR, UV-Vis, and its photocatalytic activity was tested through the photocatalytic degradation of methamidophos as a model compound under ultraviolet irradiating and in sunlight, respectively. In order to compare the photocatalytic activities, the same experiment was carried out for undoped nano-TiO₂. The degradation ratio of methamidophos in the presence of doped nano-TiO₂ reached 64.40% under sunlight for 12 h, which was 2.64% in the presence of undoped nano-TiO₂. The degradation ratio of methamidophos in the presence of doped nanoTiO₂ reached 90.39% under UV irradiationat 2.5 h, which was 51.29% in the presence of undoped nano-TiO₂. All the results show that the doped TiO₂ is a promising photocatalyst using sunlight for treating the organophosphorous pesticide wastewater. The article is published in the original.