Synthesis And Cellactivity Of Metal Sulfide Semiconductor Quantum Dots

With the development of science and technology,semiconductor quantum dot materials more and more draw scientific research workers' attention.Especially semiconductor quantum dot materials have demonstrated broad application prospects in the field of biomedical,such as the diagnosis,the treatment of medical tumors,the protein analysis and the detection.The ?A semiconductor quantum dot materials have excellent light stability,magnetism,electrical and catalytic properties,owing to their unique small size effect,surface effect,macroscopic quantum tunneling effect,quantum size effect and volume effect,and thus become one of the hot spots in the field of nanomaterials.However,the facile synthesis and new medical applications of the semiconductor quantum dot materials still need further investigation.The main research work of this paper is to explore the facile,low cost and controllable synthesis methods for the ?A semiconductor quantum dot materials,to characterize the synthesized products,and to explore the fluorescence properties of the ? A semiconductor quantum dot materials and the cell toxicity.These ? A compound semiconductor nanomaterials are: cadmium sulfide quantum dots,cadmium selenate quantum dots,cadmium telluride quantum dots and copper selenide quantum dots.The following are the main research work:(1)The CdTe/HA quantum dots with good dispersibility and uniform size were successfully synthesized through using folic acid as the biological substrate and simple water bath method.Then the photodynamic therapy of tumor cells was explored,and the toxic mechanism was further researched.The results of XRD,HRTEM,TG-DTA,FT-IR,Zeta-potential,PL,ICP-MS,FCM and DCFH-A showed that the synthesized Cd Te quantum dots are crystalline and the average particle size is 4.45 ± 0.3 nm,and not only have good fluorescence properties,but also can be stable in aqueous solution,DMEM medium,PBS,serum.Further research showed that the CdTe quantum dots have selective inhibition towards tumor cells under visible light irradiation: the specific test including BRL-3A rat normal liver cells,Hep G2 human hepatocellular carcinoma cells and HeLa human cervical cancer cells.The results showed that the quantum dots have little inhibitory effect on normal hepatocytes in rats,but have a good inhibitory effect on human hepatocellular carcinoma cells and human cervical cancer cells,and the inhibitory effect are increased withthe increase of sample concentration.The CLSM and ICP-MS tests showed that the sample is ingested into the cells by ingestion and the intake is not significantly different.In the results of the FCM test,it could be concluded that the sample is induced to inhibit the cell proliferation by inducing cell necrosis.Through the analysis of the results of the cycle,it was found that the sample mainly induces the G2 phase reproduction.The difference in intracellular reactive oxygen species further revealed the mechanism of the difference in inhibition..The reason for the increase of inhibitory effect under visible light irradiation may be the increase in the content of reactive oxygen species in the cells under visible light,and thus the inhibitory effect is increased.(2)CuSe/CS quantum dots were synthesized by using chitosan sulfate as the biological substrate under the condition of N2 protection,hereafter we studyed the effect of photodynamic action on Hep G2 cells.The results of XRD showed that the synthesized nanoparticles are crystalline.HRTEM images confirmed the size of CuSe/CS QDs with the good dispersityis is between 5 and 6 nm.The results of Zeta-potential showed that the quantum dots have good water-solubility stability.From the PL test we could observe that the quantum dots retain the better fluorescence.The results of cytotoxicity MTT assay showed that the quantum dots are more sensitive to cells under the visible light than in the dark environment.The results showed that there are almost no difference in cell intake via the ICP-MS characterization.The event of reactive oxygen test showed that the reactive oxygen species produced in the cells under the illumination conditions are significantly more than those under the dark environment.Compared with the cytotoxicity test upshot the reactive oxygen test results are consistent.These results provided an important basis for understanding the direct anticancer activity of copper selenide quantum dots and offered the potential use of copper selenide quantum dots as the photosensitizer in the Photodynamic suppression process.(3)The cadmium telluride quantum dots were synthesized by using folic acid as the biological matrix.,cadmium selenide quantum dots were synthesized by taking the chondroitin sulfate as the matrix,and the cadmium sulfide quantum dots were synthesized with the method of hydrolysis.HRTEM test results showed that: the size of synthesied quantum dots is very small below 10 nm.Fluorescence microscopy showed that the three quantum dots are fluorescent and stable in aqueous solution.The results showed that the inhibitory effects of CdS,CdSe and CdTe quantum dots on Hep G2 cells and HeLa cells present an increasing trend.After the action of quantum dots on tumor cells,the intracellular reactiveoxygen species also show an increasing trend.The results of the final study showed that the synthesized quantum dots are useful for the effective diagnosis of tumors.