Effects of Iron-Oxide Nanoparticle Surface Chemistry on Uptake Kinetics and Cytotoxicity in CHO-K1 Cells

Superparamagnetic iron-oxide nanoparticles (SPIONs) show great promise for multiple applications in biomedicine. While a number of studies have examined their safety profile, the toxicity of these particles on reproductive organs remains uncertain. The goal of this study was to evaluate the cytotoxicity of starch-coated, aminated, and PEGylated SPIONs on a cell line derived from Chinese Hamster ovaries (CHO-K1 cells). We evaluated the effect of particle diameter (50 and 100 nm) and polyethylene glycol (PEG) chain length (2k, 5k and 20k Da) on the cytotoxicity of SPIONs by investigating cell viability using the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and sulforhodamine B (SRB) assays. The kinetics and extent of SPION uptake by CHO-K1 cells was also studied, as well as the resulting generation of intracellular reactive oxygen species (ROS). Cell toxicity profiles of SPIONs correlated strongly with their cellular uptake kinetics, which was strongly dependent on surface properties of the particles. PEGylation caused a decrease in both uptake and cytotoxicity compared to aminated SPIONs. Interestingly, 2k Da PEG-modifed SPIONs displayed the lowest cellular uptake and cytotoxicity among all studied particles. These results emphasize the importance of surface coatings when engineering nanoparticles for biomedical applications.     

碳纳米管表面功能化研究进展

碳纳米管的表面功能化修饰已成为现代纳米领域的一大研究热点,对实现碳纳米管的独特约优越性起到基础性作用。文章筒述了碳纳米管（CNTs）的结构与制备方法,对碳纳米管常见的功能化修饰进行了综述,最后对碳纳米管改性高分子材料存在的问题和发展方向进行了展望。     

Potential Technological Applications of Synthetic Geomimetic Nanotubes

Geomimetic chrysotile nanotubes have a high potentiality in nanotechnological applications. These synthetic inorganic nanotubes can be used to prepare quantum wires with interesting electrical and optical properties. In fact, they behave as host systems, exhibiting a constant inner diameter inferior to 7 nm, a low tendency to aggregate and large inter-channel separation, preventing the interaction between individual guest filled nanomaterial acting as an unisosotropic confining structure. The chemical-physical properties of undoped and differently Fe doped geoinspired chrysotile synthetic nanotubes have been reviewed confirming that these characteristic features make synthetic chrysotile nanotubes excellent candidates to prepare innovative inorganic nanowires. Furthermore, the possibility to synthesize undoped geomimetic chrysotile nanotubes with high reproducibility and crystallinity avoids cytotoxicity , making them safe for human health.     

表面活性剂在碳纳米管表面处理中的应用

介绍了表面活性剂在碳纳米管表面处理中的应用及现状,探讨了表面活性剂对碳纳米管表面改性的作用机理,提出在碳纳米管表面处理中应用表面活性剂的展望。引用文献34篇     

金属纳米粒子修饰的碳纳米管研究进展

多壁和单壁碳纳米管（CNT）是被广泛研究的纳米材料之一,可以用作良好的金属或其它纳米粒子的载体。金属纳米粒子-碳纳米管复合材料在催化、传感、贮氢、及各种光学电学方面有广泛的应用前景,文章就近期各种碳纳米管负载的金属纳米材料（主要集中在贵金属）的合成做一小结。     

Symmetry-based Study of MoS2 and WS2 Nanotubes

The symmetry-based study of MS₂ (M=Mo, W) single-wall nanotubes (SWNTs) is reviewed. First, the structure and symmetry of MS₂ NTs is determined. Then, conserved quantum numbers and general forms of potentials are derived. The valence force-field method implemented into the POLSym code is used to calculate phonon dispersions. Phonons characterized by a zero angular-momentum quantum number are studied in detail. The functional dependence of the frequency of rigid layer modes on NT diameter and chirality are found, and Raman- and infrared-active modes are singled out. Electronic band structure calculations are performed by the symmetry-based density functional tight-binding (DFTB) method. Changes in the band-gap type and size with NT chirality and diameter are evaluated. Optical absorption spectra of individual NTs are calculated using DFTB wave functions for exact transition matrix element calculations. Diffraction patterns of MS₂ are predicted and NT characterization by different diffraction methods is discussed.     

Adsorption of Pyridine from Aqueous Solution by Surface Treated Carbon Nanotubes

Abstract

The surface treatment of multi‐walled carbon nanotubes (MWCNTs) with acid, heat, ultrasonic, and polyvinyl alcohol has been examined. The original CNTs and four treated CNTs were first used as adsorbents to remove pyridine from water and the adsorption isotherms of pyridine on CNTs were studied. At the same time, the effect of pH, temperature, and the adsorption kinetics on the adsorption of pyridine were also evaluated. The experiments show that the adsorption of pyridine on different CNTs is mainly a physical process and the data fit the Freundlich adsorption isotherm well. The short time needed to reach equilibrium as well as the high adsorption capacity of pyridine suggests that CNTs possess highly potential applications for pyridine removal from water.     

Carbon Nanotubes for Supercapacitor

As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs) and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage.     

无机化学教学及实验的研究

探讨了无机化学教学及实验中应重视的问题,提出了提高教学及实验质量的建议。     

碳纳米管负载铂-二氧化钌纳米颗粒催化剂的制备及表征

以多壁碳纳米管(MWNTs)为载体,采用化学还原法制备了多壁碳纳米管负载的铂-二氧化钌纳米颗粒催化剂(Pt-RuO2/MWNTs),并利用透射电镜(TEM)、电化学法等技术对该催化剂形貌和电化学性质进行了表征。结果表明,大小约为4～5nm的金属纳米颗粒均匀地分散在碳纳米管上,同时考察了该催化剂在铁氰化钾溶液中的循环伏安行为以及对该催化剂进行了电化学阻抗分析。     

Capillary Imbibition of Gadolinium Halides into WS2 Nanotubes: a Molecular Dynamics View

The structure of the molten salts GdX₃, where X denotes Cl, Br, or I, and the kinetics of their penetration into WS₂ nanotubes were investigated using molecular dynamics simulations. The GdCl₃ and GdBr₃ melts are found to comprise an amorphous framework structure with substantial intermediate-range ordering, as manifested by pair distribution, and angle-resolved pair-pair distribution functions associated with cationic correlations. In contrast, the GdI₃ melt is a liquid with short-range cationic ordering. These structural peculiarities cause dramatically different mobility of Gd cations among pure GdX₃ melts and explain the relative difference in the capillary activity of WS₂ nanotubes regarding the melts, as observed in preliminary experiments. Extended MD simulations of GdCl₃ dissolved in molten KCl predict the total degradation of the GdCl₃ framework structure below 40 mol %, although no essential uptake of Gd cations by the WS₂ nanotube is observed, due to more progressive diffusion of K cations. Our theory suggests that, among the considered halides, only the GdI₃ compound is suitable for Gd encapsulation into WS₂ nanotubes employing the capillary technique.     

Effect of Dispersants on the Electrophoretic Deposition of Hydroxyapatite‐Carbon Nanotubes Nanocomposite Coatings

Isopropanolic Suspensions of HA nanoparticles (20 g/L) plus various concentrations of carbon nanotubes (CNTs) were prepared using Tris and triethanolamine as dispersant. The positively charged HA nanoparticles were heterocoagulated on the negatively charged CNTs and generated the HA‐CNT composite particles with net positive surface charge. The heterocoagulation was more intensive in dispersant‐containing suspensions (DCS) due to the higher zeta potential of HA nanoparticles in them. HA‐CNTs particles can be rotated and aligned parallel to electric field as a result of torque exerted on them due to the generation of a dipole moment in CNTs during electrophoretic deposition (EPD). The mobility of HA‐CNTs particles aligned parallel to electric field is ≈50% higher than that of HA nanoparticles leading to the faster EPD from DCS when CNTs are added into them. CNTs more efficiently reinforced the coatings deposited from DCS due to the stronger electrostatic bonding between CNTs and HA nanoparticles in them.     

碳纳米管对活性污泥胞外聚合物的吸附特性研究

以单壁碳纳米管(SWNTs)为吸附剂,系统地研究了其对活性污泥胞外聚合物(EPS)的吸附特性.结果表明,SWNTs能够快速吸附EPS,当吸附剂投加量为0.9 g/L时,吸附在20 min即可达到平衡,吸附动力学符合准二级动力学模型.吸附等温线能较好地用Langmuir 吸附等温模型来描述,最大单分子吸附量为123.577 mg/g.pH值对吸附有较大影响,最佳吸附pH范围为5～7.     

碳纳米管功能化的途径、机理和表面特征

由碳纳米管的功能化有共价键和非共价键两种方法。共价键功能化的机理是通过氧化或还原反应在碳纳米管表面生成极性或反应性基团(表面基团化),继而通过化学反应使碳纳米管表面有机化或聚合物化。非共价键功能化的机理是基于碳纳米管表面的?体系和疏水性可与含?电子的芳烯化合物发生?-?相互作用或与含疏水链的表面活性剂发生物理吸附。本文综述碳纳米管功能化的研究进展,完善了Kim等提出的碳纳米管功能化表面的代数表示:表面基团化的为1G,表面有机化的为2G,表面聚合物化的为3G。     

多壁碳纳米管的表面改性及其在水性聚氨酯体系中的应用

采用自制的硅烷类改性剂(s-PEG)对经过酸氧化的多壁碳纳米管(MWNTs)进行表面改性处理,并通过共混法制备了MWNTs/水性聚氨酯(WPU)复合材料,研究了MWNTs的添加对复合材料性能的影响.结果表明,改性剂s-PEG成功地包覆于MWNTs表面,形成了s-PEG壳层,包覆率约为25％.改性MWNTs (s-PEG-MWNTs)的添加可以明显改善WPU复合材料的拉伸性能,当s-PEG-MWNTs的添加量为1％时,复合材料的拉伸强度和断裂伸长率比未添加MWNTs的材料分别提高了597％和152％.s-PEG-MWNTs在WPU基体中达到了良好的分散效果.此外,s-PEG-MWNTs的添加显著地增强了复合材料的导电性能.     

纳米Ni及碳纳米管对AP热分解的催化性能

分别用溶液还原法和化学沉淀法制备出了纳米NiNi／CNTs复合催化剂粒子,并用TEM,SEM,XRD,FT—IR对其进行了表征;运用差热分析（DTA）研究了纳米Ni及Ni／CNTs复合催化剂粒子对AP热分解性能的影响。结果表明。纳米Ni使AP热分解的高温分解峰温降低104．47C,纳米Ni／CNTs复合催化剂粒子可使AP热分解的高温分解峰温降低137．05℃,证明碳纳米管在纳米Ni对AP热分解的催化过程中起到了很好的助催化作用。     

POM/MWNTs-PEG复合材料的制备和结晶性能研究

采用原子转移自由基聚合的方法将聚乙二醇（PEG）接枝到多壁碳纳米管（MWNTs）上,然后利用平板硫化机制备出聚甲醛（POM）/MWNTs-PEG复合材料。利用扫描电子显微镜、透射电子显微镜、红外光谱和热重分析对MWNTs-PEG进行表征。通过差式扫描量热仪研究了该复合材料结晶行为的变化,用Jeziorny法和Mo法对其进行非等温结晶动力学分析。结果表明,PEG均匀接枝到MWNTs上;MWNTs-PEG的加入具有异相成核的作用,使POM结晶温度向高温区移动,结晶速率提高,半结晶时间缩短;结晶速率常数值增加,F(T)值降低;有效结晶活化能降低;MWNTs-PEG最终起到促进POM结晶的作用。     

碳纳米管的制备

作为纳米材料典型代表之一的碳纳米管自被发现以来 ,以其独特的结构和性能引起了人们广泛的关注 ,本文简介了碳纳米管的发展和现状 ,详细阐述了碳纳米管的几种制备方法。     

Description of Release Process of Doxorubicin from Modified Carbon Nanotubes

The article discusses the release process of doxorubicin hydrochloride (DOX) from multi-wall carbon nanotubes (MWCNTs). The studies described a probable mechanism of release and actions between the surface of functionalized MWCNTs and anticancer drugs. The surface of carbon nanotubes (CNTs) has been modified via treatment in nitric acid to optimize the adsorption and release process. The modification efficiency and physicochemical properties of the MWCNTs+DOX system were analyzed by using SEM, TEM, EDS, FTIR, Raman Spectroscopy and UV-Vis methods. Based on computer simulations at pH 7.4 and the experiment at pH 5.4, the kinetics and the mechanism of DOX release from MWNT were discussed. It has been experimentally observed that the acidic pH (5.4) is appropriate for the efficient release of the drug from CNTs. It was noted that under acidic pH conditions, which is typical for the tumour microenvironment almost 90% of the drug was released in a relatively short time. The kinetics models based on different mathematical functions were used to describe the release mechanism of drugs from MWCNTs. Our studies indicated that the best fit of experimental kinetic curves of release has been observed for the Power-law model and the fitted parameters suggest that the drug release mechanism of DOX from MWCNTs is controlled by Fickian diffusion. Molecular dynamics simulations, on the other hand, have shown that in a neutral pH solution, which is close to the blood pH, the release process does not occur keeping the aggregation level constant. The presented studies have shown that MWCNTs are promising carriers of anticancer drugs that, depending on the surface modification, can exhibit different adsorption mechanisms and release.     

CdS纳米管合成方法研究进展

作为一种典型的光电半导体材料,硫化镉(CdS)一维纳米材料的合成近年来受到人们的广泛关注.本文综述了阳极氧化铝(AAO)、聚四氟乙烯(PTFE)硬模板,聚乙烯醇(PVA)软模板和超声化学法合成一维CdS纳米管,介绍了各种合成方法中CdS纳米管的形成机制.