Study The Toxic Effects Of Nanoparticles On Vascular Endothelial Cells

Since the beginning of 1990's,nano-science and technology gained rapid development,and has been widely applied in the areas of electronics,information and communication,semiconductor,biology and medicine.More and more countries have been putting huge investment in the research and development of nanotechnology for the purpose of taking advantage of the opportunities which could bring huge commercial benefits.However,the bio-safety of nanomaterials has been drawing increasing attention of scientists and environmental protection organization.Preliminary studies showed that some kinds of nano-scale materials might have negative impact on human beings.Greater effort is urgently needed on the evaluation of the bio-safety of nano-scale materials for the healthy development of nanotechnology.The current study was aimed at investigating the interactions between nanomaterials and the vascular endothelial cells,which includes the following four parts:1.Isolation and identification of vascular endothelial cells(VECs) from human umbilical vein.The morphologic observation and evaluation of ECs were made with light microscopy,electron microscopy and immunohistochemistry.The results showed that the isolated VECs arrayed like pitching stones under light microscope.W-P corpuscles were observed in the cytoplasm under electron microscope and immunostaining of the cells with antibody againstⅧfactor demonstrated positive reaction,suggesting that the isolated cells were VECs.2.Study on the effect of surface chemistry of MWNT on the cytotoxicity.It was demonstrated that the cytotoxicity of p-CNTs was greater than that of f-CNTs at 24 h of exposure.However it was on the contrary at 48 h and 72 h of exposure.Transmission electron microscopic observation showed that there were much more CNT aggregates in the cells in contact with f-CNTs,but the p-CNT aggregates were much more condensed than f-CNTs aggregates.These observations suggested that the modification of CNTs have effects on cellular function that can not be attribute to one factor alone,but are more likely the combined result of several unfavorable interactions.3.Study of the effect of the length of MWCNTs on the cytotoxicity.(MWCNTs). The results showed that the 50μm-long MWCNTs induced more severe damages to the vascular endothelial cells(VECs) in comparison to the 0.5μm-long MWCNTs.It was also demonstrated that the long CNTs at 50μg/mL induced significantly higher number of apoptotic cells than the short MWCNTs.It provided the first evidence that CNT aggregates with a dimension of up to 10μm×6.25μm were internalized by VECs and caused severe damages,which is postulated as a new mechanism underlying the cellular injuries induced by aggregated CNTs.4.Evaluation of the arginine modified chitosan(Arg-CS) as gene carriers for introducing tissue factor pathway inhibitor(TFPI) gene into VECs.The level of TFPI mRNA was tested using RT-PCR ant the in vitro cytotoxicity of Arg-CS/DNA complexes was determined by MTT assay.The results showed that Arg-CS/pIRES-TFPI DNA complexes were nontoxic to the VECs and successfully mediated the expression of TFPI gene in the cells.