Sensitivity of Different Cytotoxic Responses of Vero Cells Exposed to Organic Chemical Pollutants and their Reliability in the Bio-toxicity Test of Trace Chemical Pollutants

Objective To find a sensitive cytotoxic response to reflect the bio-toxicity of trace organic pollutants, the sensitivity and reliability of morphological change and proliferation inhibition of Vero cells exposed to 2, 4, 6-trichlorophenol （TCP） and the leachate from products related to drinking water （PRDW） were compared, and the mechanism of the morphological change in Vero cells exposed to chemical pollutants was studied. Methods Vero cells were treated by different concentration of TCP and the leachate from PRDW. Methylthiazol-2-yl-2, 5-diphenyl tetrazolium bromide （MTT） assay was carried out for proliferation inhibition. Bioluminescence method was carried out as another method to test the toxicity of TCP. Flow Cytometry assay was used to test cell Apoptosis and damage of cell-membrane. Results 0.25 mg/L TCP had an effect on cell morphology, and the proportion of morphologically changed cells increased with increasing TCP concentration. At low TCP concentrations, inhibition of cell proliferation did not seem to correlate to TCP concentration, and was negative when TCP concentration was 〈1.0 mg/L. After exposure to leachate from PRDW extracted at different temperatures, the percentage of morphologically changed cells increased with extracting temperature, but the inhibition of cell proliferation failed to reflect the correlation between extracting temperature and proliferation inhibition of Vero cells. Although the Sensitivity of bioluminescence method seems to be similar to morphological change in Veto cells, the bacterial in this method is not homologous enough with human body cells to reflect the toxicity to human body. These imply cell morphological change is a more sensitive and reliable method to reflect bio-toxicity of organic pollutants than proliferation inhibition. Flow cytometry analysis and cell rejuvenation experiments indicated cell membrane damage, which results in cell morphological change, was an early and sensitive cytotoxic response comparing with necrosis. Conelusion These results indicated that the cell membrane toxicity represented by morphological changes is a more sensitive and reliable method to indicate the composite bio-toxicity of trace chemicals than proliferation inhibition, inhibition on bioluminescence and necrosis. Nevertheless, the quantification of morphological change should be studied further.

氯代苯和部分氯代酚的生物活(或毒)性定量研究

在分子拓扑理论的基础上,根据分子中成键原子i价层电子结构特征和所处的化学环境,提出一个新的计算顶点原子价点价δYi方法:δY i=mi Z(i-hi)+ΣLi×L[()]j/n2i[L(i+1)/pi],以δYi为基础构建了价连接性指数mYt,通过逐步回归法对化合物的拓扑参数进行筛选,所得最佳参数与氯代苯和部分氯代酚的生物活(或毒)性进行定量构效关系研究(QSAR)。结果表明:2D(Two-dimensional)指数mYt和3D(Threedimensional)指数QC对这些化合物的生物活(或毒)性具有良好的结构选择性,且所建模型具有良好的预测能力、较好的可靠性和稳健性。

Suspended particle effects on ClO_2/ultraviolet light combined disinfection of effluent

The concentration of suspended solids of effluent often varies in a wide range, therefore the dose of ultraviolet light （UV） in disinfection process needs to be adjusted to meet the disinfection criterion at a high frequency, and the desired disinfection effect is difficult to be ensured. The particles size and particle-associated fecal coliform （F.C.） contribution, and their influence on UV disinfection were investigated when ClO2 and UV combined disinfection process was used. The results showed that suspended solids content had a major impact on UV disinfection efficiency, especially the large particle size fraction. Particles （D〉10μm） associated F. C. were difficult to be disinfected and were the main part of the railings of F.C. inactivation curve. Pre-ClO2 oxidation could reduce the number of particles in effluent, and make large particles decrease to small ones. Therefore, the influence of particles on UV disinfection could be reduced after pre-ClO2 oxidation, and the resistance ability to particle loadings of combined process was enhanced. Moreover, the combined process has a lot of advantages, such as low toxicity, low operational/maintenance costs; it is also convenient to be established in the existing wastewater plant or the new planned one.

Biotoxicity of CdS/CdSe Core-Shell Nano-Structures

The cytotoxicity of hydrophobic QDs CdS/CdSe was tested assigning MTT assay on Human Embryonic Kidney cells (HEK-293), breast cancer cells (MCF-7) and Enrichlish Ascitices Cells (EAC). Approximately 65% bio-toxicity was observed in MCF-7 for the core-shell QDs. These QDs may also find effective applications in other optoelectronic devices. CdS/CdSe core-shell hetrostructure quantum dots (QDs) were generated by chemical reaction between the respective chalcogens and cadmium metal salt. Sulphur powder was utilized for CdS core preparation while selenium was extracted from an organoselenium compound to impart CdSe shell layer at a temperature between 150℃ - 200℃. So-prepared core-shell QDs showed good optical properties. The particle size was found to be in the range of 3 - 4 nm with spherical morphology and cubic crystal structure.

Toxic effects of metal oxide nanoparticles and their underlying mechanisms

Nanomaterials have attracted considerable interest owing to their unique physicochemical properties.The wide application of nanomaterials has raised many concerns about their potential risks to human health and the environment.Metal oxide nanopartides（MONPs）,one of the main members of nanomaterials,have been applied in various fields,such as food,medicine,cosmetics,and sensors.This review highlights the bio-toxic effects of widely applied MONPs and their underlying mechanisms.Two main underlying toxicity mechanisms,reactive oxygen species（ROS）-and non-ROS-mediated toxidties,of MONPs have been widely accepted.ROS activates oxidative stress,which leads to lipid peroxidation and cell membrane damage.In addition,ROS can trigger the apoptotic pathway by activating caspase-9 and-3.Non-ROS-mediated toxicity mechanism includes the effect of released ions,excessive accumulation of NPs on the cell surface,and combination of NPs with specific death receptors.Furthermore,the combined toxicity evaluation of some MONPs is also discussed.Toxicity may dramatically change when nanomaterials are used in a combined system because the characteristics of NPs that play a key role in their toxicity such as size,surface properties,and chemical nature in the complex system are different from the pristine NPs.

Biocompatibility and biotoxicity of in-situ synthesized carboxylated nanodiamond-cobalt oxide nanocomposite

A nanocomposite that incorporates cobalt oxide（Co3O4） and nanodiamond（ND） can present both high magnetism（Co3O4） and high hardness（ND）. ND particles have potential applications in a variety of fields such as protein immobilization, biosensors, therapeutic molecule delivery and bio-imaging. However,limited information is available in literature on the in-situ synthesis of biocompatible magnetic materials and also on their potential biotoxicity as a result of their entry into environmental compartments and subsequent interaction with biota. In this work, a new kind of bio-compatible magnetic material –carboxylated nanodiamond（c ND） and Co3O4 was synthesized to obtain the c ND-Co3O4 nanocomposite.The synthesis procedure involved in-situ and chemical reduction of cobalt chloride（CoCl（26）H2O） and sodium borohydrate（NaBH4）. The synthesized cND-Co3O4 nanocomposite was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The cyto-genotoxicity of the synthesized nanocomposite material was studied by using onion（Allium cepa L.） as a test model with concentrations of 5, 10 and 20 μg/ml. The study was also extended to cND and Co3O4 materials for comparison purpose. Co3O4 and cND exhibited their contrasting effects on mitosis and other cyto-genotoxic indices studied herein. This work provided fundamental data on the synthesis and the bio-toxicity of the c ND-Co3O4 nanocomposite, which, in turn, can help to expand their multidisciplinary applications.