Size-dependent cytotoxicity of gold nanoparticles

Gold nanoparticles are widely used in biomedical imaging and diagnostic tests. Based on their established use in the laboratory and the chemical stability of Au(0), gold nanoparticles were expected to be safe. The recent literature, however, contains conflicting data regarding the cytotoxicity of gold nanoparticles. Against this background a systematic study of water-soluble gold nanoparticles stabilized by triphenylphosphine derivatives ranging in size from 0.8 to 15 nm is made. The cytotoxicity of these particles in four cell lines representing major functional cell types with barrier and phagocyte function are tested. Connective tissue fibroblasts, epithelial cells, macrophages, and melanoma cells prove most sensitive to gold particles 1.4 nm in size, which results in IC(50) values ranging from 30 to 56 microM depending on the particular 1.4-nm Au compound-cell line combination. In contrast, gold particles 15 nm in size and Tauredon (gold thiomalate) are nontoxic at up to 60-fold and 100-fold higher concentrations, respectively. The cellular response is size dependent, in that 1.4-nm particles cause predominantly rapid cell death by necrosis within 12 h while closely related particles 1.2 nm in diameter effect predominantly programmed cell death by apoptosis.     

Porous ternary complex metal oxide nanoparticles converted from core/shell nanoparticles

We demonstrate an easy and scalable low-temperature process to convert porous ternary complex metal oxide nanoparticles from solution-synthesized core/shell metal oxide nanoparticles by thermal annealing. The final products demonstrate superior electrochemical properties with a large capacity and high stability during fast charging/discharging cycles for potential applications as advanced lithium-ion battery (LIB) electrode materials. In addition, a new breakdown mechanism was observed on these novel electrode materials.

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Preparation,characterisation and in vitro cytotoxicity studies of chelerythrine-loaded magnetic Fe3O4@O-carboxymethylchitosan nanoparticles

In this work, a novel, active tumour-targeting system (Fe₃O₄@OCMCS-CHE) was designed by surface-modifying superparamagnetic iron oxide nanoparticles (Fe₃O₄) with O-carboxymethylchitosan (OCMCS) to improve their biocompatibility and ability to target specific tumour cells. The chelerythrine (CHE) was used as the model of anti-tumour drug in this system. The optimised formulation was characterised and confirmed by scanning electron microscopy (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), in vitro drug release and so on. It was found that the synthesised nanoparticles were spherical in shape with an average size of 60 nm, the drug loading content and entrapment efficiency were 8.32 ± 0.25% (w/w) and 90.65 ± 0.46% (w/w), respectively, and the saturated magnetisation reached 27.06 emu/g. The in vitro drug-release behaviour from nanoparticles displayed a biphasic drug-release pattern with initial burst release and consequently sustained release. Also, the effect of magnetic targeted nanoparticles on the proliferation of human hepatoma cell line (HepG2) in vitro was investigated. The results from 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and Hochest assays suggested that the Fe₃O₄@OCMCS-CHE nanoparticles could effectively inhibit the proliferation of HepG2 cells, which displayed time-dependent and concentration-dependent manner. All these results indicated that the multifunctional Fe₃O₄@OCMCS nanoparticles possess a high drug loading efficiency, have low cytotoxicity, and are promising candidates for targeted drug delivery.     

Reagent control over the composition of mixed metal oxide nanoparticles

Binary (M¹ ? M² ? O) and ternary (M¹ ? M² ? M³ ? O) metal-oxide nanoparticles (NPs) have been prepared by thermal decomposition in benzyl ether of the appropriate M(acac)_n (M = Fe, Mn, Pd, Cu, Al, Gd) compounds in the presence of a mixture of oleic acid and oleylamine templating (surface capping) ligands, and 1,2-hexadecanediol as an accelerating agent. The metal percentage and the particle size were investigated as a function of the starting composition. The NP composition is controlled by the relative reaction rates of the particular precursors, such that prediction of NP composition from reagent ratios is not straightforward. However, understanding reaction rate limitations allows for alternative synthesis to be developed. In some cases, ligand exchange reaction and subsequent decomposition are possibly more important than thermal decomposition.     

Green nanochemistry: metal oxide nanoparticles and porous thin films from bare metal powders

A universal, simple, robust, widely applicable and cost-effective aqueous process is described for a controlled oxidative dissolution process of micrometer-sized metal powders to form high-purity aqueous dispersions of colloidally stable 3-8 nm metal oxide nanoparticles. Their utilization for making single and multilayer optically transparent high-surface-area nanoporous films is demonstrated. This facile synthesis is anticipated to find numerous applications in materials science, engineering, and nanomedicine.     

Comparative cytotoxicity evaluation of different size gold nanoparticles in human dermal fibroblasts

The aim of this work was to compare the effects of three commercially available gold nanoparticles (AuNPs) of different sizes (30, 50 and 90 nm) on the viability of normal human dermal fibroblasts (NHDF). In addition, we evaluated protective effect of N-Acetyl-L-cysteine (NAC), total glutathione content (GSH/GSSG), superoxide dismutase (SOD) activity and reactive oxygen species (ROS) production to investigate if oxidative stress was involved in the cytotoxic response of these AuNPs. Although AuNP-induced cytotoxicity was dose and time dependent, nanoparticle size slightly influenced the cytotoxic response of AuNPs assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase. Regarding oxidative parameters, NAC produced no significant protection of NHDF cells against treatment with any of the three AuNPs. Independently on nanoparticle size, GSH/GSSG content was drastically depleted after 24 h of incubation with the three AuNPs (less than 15% in all cases), while no statistically significant changes on SOD activity were reported (～90% of activity). The three AuNPs also caused a notable increase in the ROS production of NHDF cells. In conclusion, our data suggest that AuNP-induced cytotoxicity in NHDF is mediated by oxidative stress and it is independent of nanoparticle size.     

Enhancement of radiation cytotoxicity in breast-cancer cells by localized attachment of gold nanoparticles

Gold nanoparticles (GNPs) and modified GNPs having two kinds of functional molecules, cysteamine (AET) and thioglucose (Glu), are synthesized. Cell uptake and radiation cytotoxicity enhancement in a breast-cancer cell line (MCF-7) versus a nonmalignant breast-cell line (MCF-10A) are studied. Transmission electron microscopy (TEM) results show that cancer cells take up functional Glu-GNPs significantly more than naked GNPs. The TEM results also indicate that AET-capped GNPs are mostly bound to the MCF-7 cell membrane, while Glu-GNPs enter the cells and are distributed in the cytoplasm. After MCF-7 cell uptake of Glu-GNPs, or binding of AET-GNPs, the in vitro cytotoxicity effects are observed at 24, 48, and 72 hours. The results show that these functional GNPs have little or no toxicity to these cells. To validate the enhanced killing effect on cancer cells, various forms of radiation are applied such as 200 kVp X-rays and gamma-rays, to the cells, both with and without functional GNPs. By comparison with irradiation alone, the results show that GNPs significantly enhance cancer killing.     

Preparation and characterization of zeolite framework stabilized cuprous oxide nanoparticles

Zeolite framework stabilized copper(I) oxide nanoparticles (4.8 ± 2.6 nm) were prepared for the first time by using a four step procedure: the ion exchange of Cu²⁺ ions with the extra framework Na⁺ ions in Zeolite-Y, the reduction of the Cu²⁺ ions within the cavities of zeolite with sodium borohydride in aqueous solution, the dehydration of Zeolite-Y with the copper(0) nanoclusters, and the oxidation of intrazeolite copper(0) nanoclusters by O₂ at room temperature. Zeolite stabilized copper(I) oxide nanoparticles were thoroughly characterized by ICP-OES, XRD, HR-TEM, Raman, XPS, UV-vis spectroscopy and N₂ adsorption-desorption technique.     

Image-guided prostate cancer therapy using aptamer-functionalized thermally cross-linked superparamagnetic iron oxide nanoparticles

CG-rich duplex containing prostate-specific membrane antigen (PSMA) aptamer-conjugated thermally cross-linked superparamagnetic iron oxide nanoparticles (TCL-SPIONs) is reported as prostate cancer-specific nanotheranostic agents. These agents are capable of prostate tumor detection in vivo by magnetic resonance imaging (MRI) and selective delivery of drugs to the tumor tissue, simultaneously. The prepared PSMA-functionalized TCL-SPION via a hybridization method (Apt-hybr-TCL-SPION) exhibited preferential binding towards target prostate-cancer cells (LNCaP, PSMA+) in both in vitro and in vivo when analyzed by T(2) -weighted MRI. After Dox molecules were loaded onto the Apt-hybr-TCL-SPION through the intercalation of Dox to the CG-rich duplex containing PSMA aptamer as well as electrostatic interaction between the Dox-and-polymer coating layer of the nanoparticles, the resulting Dox@Apt-hybr-TCL-SPION showed selective drug-delivery efficacy in the LNCaP xenograft mouse model. These results suggest that Dox@Apt-hybr-TCL-SPION has potential for use as novel prostate cancer-specific nanotheranostics.     

聚合物-过渡金属氧化物纳米复合阴极材料的研究进展

聚合物－过渡金属氧化物纳米复合阴极材料在锂二次电池中是一类具有广阔应用前景的新型材料，本文综述了这类材料的制备方法和性能特征，分析了其导电机理，探讨了该研究领域的前沿问题。     

Amperometric acetylcholinesterase biosensor for pesticides monitoring utilising iron oxide nanoparticles and poly(indole-5-carboxylic acid)

A new electrochemical sensing device was constructed for determination of pesticides. In this report, acetylcholinesterase was bioconjugated onto hybrid nanocomposite, i.e. iron oxide nanoparticles and poly(indole-5-carboxylic acid) (Fe₃O₄NPs/Pin5COOH) was deposited electrochemically on glassy carbon electrode. Fe₃O₄NPs was showed as an amplified sensing interface at lower voltage which makes the sensor more sensitive and specific. The enzyme inhibition by pesticides was detected within concentrations ranges between 0.1–60 and 1.5–70 nM for malathion and chlorpyrifos, respectively, under optimal experimental conditions (sodium phosphate buffer, pH 7.0 and 25?°C). Biosensor determined the pesticides level in water samples (spiked) with satisfactory accuracy (96%–100%). Sensor showed good storage stability and retained 50% of its initial activity within 70 days at 4 °C.     

原子层淀积制备金属氧化物薄膜研究进展

原子层淀积(ALD)技术作为一种先进的薄膜制备方法近年来越来越得到重视,它能精确地控制薄膜的厚度和组分,实现原子层级的生长,生长的薄膜具有很好的均匀性和保形性,因而在微电子和光电子等领域有广泛的应用前景。本文综述了ALD技术的基本原理,及其在金属氧化物薄膜制备上的研究进展。     

Green synthesis of metal/C and metal oxide/C films by using natural membrane as support

A protocol aiming at making use of the huge amount of naturally existing wastes such as defoliation, pericarp and egg shell for nanostructured composite materials was proposed. In this study, a green synthetic route using naturally existing membrane as support was developed for the synthesis of nanostructured and porous metalor metal oxide-carbon composite films. Different metallic ions （Co2＋, Ni2＋, Fe3＋, Mn2＋ or Cu2＋） can be easily adsorbed onto egg membranes and the followed calcination process results in the formation of Co/C, Ni/C, Fe304/C, MnO/C or CulCu2OICuOIC composite films. The electrochemical studies demonstrate that such composite films would have potential applications in energy fields. This method would provide a general green concept for chemical synthesis and be beneficial to the global sustainable future.     

钛基贱金属氧化物涂层阳极的研究进展

介绍了钛基贱金属氧化物涂层阳极的发展概状。论述了贱金属氧化物涂层阳极技术发展的必然和要解决的关键问题。重点阐述了几种有代表性、具有广阔应用前景的贱金属氧化物涂层阳极，并对其未来的发展及应用前景进行了展望．     

Formation of chromium rich oxide scales for protection against metal dusting

Abstract

Metal dusting is a disintegration of metals and alloys into graphite and metal particles, caused by strongly carburizing gas mixtures mainly in the temperature range 400–700°C. Protection of steels against metal dusting is possible through the formation of dense chromium rich oxide scales but it is not guaranteed that such scales are formed at low temperatures, even on high Cr-steels.

Surface analytical studies have been conducted on the formation and composition of the oxide scales on 9–20%Cr steels. The growth of oxide films was followed by AES for 3 hours at 10^–7 mbar O₂ great differences were observed in dependence on surface finish. On ground samples, Mn and Si appeared early and Cr-rich oxide was formed, whereas on chemically etched samples Fe-rich oxides grew.

After long term exposures (240 h) under metal dusting conditions, i.e. in CO–H₂–H₂O mixtures at 600°C, thin Cr-rich scales were observed on ground steels which were impermeable to carbon whereas on chemically etched steels thick Fe-rich scales had grown and carbon penetration was detectable. Accordingly, the oxide formation on Cr-steels at relatively low temperatures strongly depends on the surface treatment. Any surface working such as grinding and sand-blasting etc. introduces dislocations and causes a fine-grained microstructure near the surface, and the dislocations and grain boundaries act as rapid diffusion paths for supply of Cr to the surface in the first minutes of exposure, which leads to the formation of a protective oxide scale.     

Photocatalytic degradation of selected pharmaceuticals using green fabricated zinc oxide nanoparticles

Heterogeneous photocatalysis is one of the popular alternative treatment methods for wastewater. It utilizes semiconductor material as the catalyst and metal oxide such as zinc oxide nanoparticles (ZnO NPs), emerged as the commonly used catalyst. In this study, a series of biogenic ZnO NPs was fabricated through precipitation method with pullulan as the biomaterial. The amount of zinc salt in the presence of pullulan was varied to study its impact on the generated ZnO NPs. The results showed that without pullulan, the average particle size of ZnO NPs obtained was 110.86 nm. With 0.84 M zinc salt in 50 g/L of pullulan, the ZnO NPs average particle size significantly reduced to 58.13 nm. The surface area of all synthesized ZnO NPs ranging from 14.84 to 19.99 m² g^?1. The photocatalytic activities of all synthesized ZnO NPs were evaluated through the photodegradation of two drugs, amoxicillin (AMX) and paracetamol (PCT). Through the comparison of drugs’ photodegradation with all synthesized ZnO NPs, ZnO NPs produced with 0.67 M zinc salt in 50 g/L of pullulan showed the highest degradation percentage of 85.7% and 96.8% for AMX and PCT respectively. The best photodegradation conditions for the drugs were 30 ppm drugs concentration, pH 9 (for AMX) and pH 5 (for PCT) and 50 mg catalyst dosage. Based on these results, biogenic ZnO NPs has high potential to be used in the treatment of pharmaceutical wastewater.     

壳聚糖修饰氧化铁磁性纳米颗粒的制备和性能研究

通过共沉淀法制备氧化铁磁性纳米颗粒,用壳聚糖对其表面进行修饰得到样品(CS@MNPs);表征其形貌结构、尺寸、表面基团、表面电荷、磁学性质和在不同介质中的稳定性等。实验结果表明,CS@MNPs具有典型的立方反尖晶石晶体结构;粒径为16.5nm;在生理(pH值7.4)条件下拥有较高的正电荷(10mV);呈现超顺磁性,对驰豫时间T1、T2,尤其是T2*具有很强的响应;在双蒸馏水和含10%新生牛血清的RPMI 1640培养液中具有良好的稳定性,具有作为磁共振造影剂的潜力。     

M2 macrophage-targeted iron oxide nanoparticles for magnetic resonance image-guided magnetic hyperthermia therapy

Tumor-associated macrophages (TAMs) play an important role in tumor development and progression.In particular,M2 TAMs can promote tumor growth by facilitating tumor progression and malignant behav-iors.Selectively targeted elimination of M2 TAMs to inhibit tumor progression is of great significance for cancer treatment.Iron oxide nanoparticles based magnetic hyperthermia therapy (MHT) is a classical approach to destroy tumor tissue with deep penetration depth.In this study,we developed a typical M2 macrophage-targeted peptide (M2pep) functionalized superparamagnetic iron oxide nanoparticle(SPIO) for magnetic resonance imaging (MRI)-guided MHT in an orthotopic breast cancer mouse model,The obtained multifunctional SPIO-M2pep with a hydrodynamic diameter of 20 nm showed efficient targeting capability,high transverse relaxivity (149 mM-1 s-1) and satisfactory magnetic hyperthermia performance in vitro.In vivo studies demonstrated that the SPIO-M2pep based MRI can monitor the distri-bution of nanoparticles in tumor and indicate the suitable timing for MHT.The M2 macrophage-targeted MHT significantly reduced the tumor volume and the population of pro-tumoral M2 TAMs in tumor.In addition,the SPIO-M2pep based MHT can remodel the tumor immune microenvironment (TIME).The multifunctional SPIO-M2pep with M2 macrophage-targeting ability,high magnetic hyperthermia effi-ciency,MR imaging capability and effective role in remodeling the TIME hold great potential to improve clinical cancer therapy outcomes.