Toxicity And Mechanism Of Quantum Dots On Late Pregnancy Mice

Objective:1.Characterize the basic physical properties and fluorescence properties of quantum dots?QDs?.Understanding the feasibility of quantum dots as biomedical fluorescent dyes.2.Explore the potential toxicity of Quantum dots?QDs?during late pregnancy by investigating the effects of CdSe/ZnS QDs and CdSe QDs on the pregnant mice and the fetus,as well as the pregnancy outcomes.3.Set a CdCl₂ controlled trial,to compare the effect of"nanoparticle"and"cadmium"in the reproductive toxicity of QDs.4.Explore the mechanisms of QDs toxicity by testing the structure,function and gene expression of placenta?which is the critical organ during pregnancy?.Method:Use the dynamic light scattering?DLS?fluorescent spectroscopy to test the hydrated diameter and fluorescence spectra of CdSe/ZnS QDs and CdSe QDs.Solutions of the different treatment materials were administered by tail vein injection at GD16,GD17.Blood,placenta,fetus,and uterus were collected at GD18.The gestational sac was visually inspected and the weight of the placenta,fetus,and uterus were recorded.ICP-MS was used to analyze Cd ions concentrations and distribution in the gestation tissue.The serum levels of various sex hormones were tested by radio immunity assay?RIA?,while several placenta polypeptides were evaluated by enzyme-linked immunosorbent assay?ELISA?.The genes related to cell apoptosis,dysplasia,metal transport,cryptorrhea,and oxidative stress were tested by RT-PCR assay.All the results were compared with CdCl₂ treatment group to investigate the molecular mechanism of QDs toxicity.Result:1.The particles of CdSe/ZnS QDs and CdSe QDs were well-resolved in water with a small average hydrodynamic diameter.The absorption spectrum of QDs covered a broad range,and the emission peak was narrow and symmetrical.2.CdSe QDs caused the most serious aberrations including the most severe malformations of the placenta and fetus,changes in placental hormone secretion levels,and gene expression levels.The CdSe/ZnS QDs and CdCl₂ treatment group were effected on the expression of genes only.3.The Cd contents of placenta in the CdSe QDs was the highest,the CdSe/ZnS QDs groups was the next and the CdCl₂ group was much lower.However,the Cd contents of fetus in all three treatment groups have no statistical differences with the control group.Conclusion:1.CdSe QDs in late pregnancy mice has obvious toxic effects,while the effects of CdSe/ZnS QDs and CdCl₂ were weak.2.Cd are the important factors influencing the toxic effect of QDs,coating materials can week the toxicity by reducing the release of Cd.3.The characteristics of nanoparticle is the prerequisite for the toxic effect of QDs.