Synthesis And Characterization Of Fluorescent Polymer Quantum Dots And Their Reproductive Toxicity Studie

Fluorescent nano-probe quantum dots(QDs)were widely used in cell imaging,drug delivering,molecular tracking and tumor targeting for their excellent optical properties.However,with the extensive research on QDs,researchers found that some kinds of heavy metal containing QDs(such as CdSe,CdTe and so on)will degrade and release divalent metal ions and further induce a series of toxic side effects when they were used in the body,which has become the largest obstacle to the clinical application of Cd-containing QDs.For this reason,people started to study other new fluorescent nano-probes,such as polymer dots(Pdots).Pdots are prepared by polymer material and could emit fluorescence when excited.The biggest feature of Pdots is that such nanoparticle doesn't contain metal elements and shows high fluorescent brightness and good optical stability.They are great fluorescent nano-probes with good biocompatibility.Recently,people have started to do some researches of Pdots on biomedical area,they found that Pdots also can be used in cell labeling,in vivo tumor targeting and photodynamic therapy and so on.However,the biological effect of Pdots has not been reported.In this study,we synthesized,characterized,modified the Pdots,and investigated the biological effect of Pdots.The main content of the thesis is listed as following:1.The synthesis,surface modification and cell imaging of Pdots We synthesized three kinds of Pdots(PF10DBT,CNPPV and PFBT/PF-DBT5)with different emission wavelengths by the way of reprecipitation.We conjugated the streptavidin(SA)to the surface of Pdots for improving their biological compatibility.The non-conjugated Pdots and conjugated Pdots(Pdots-SA)were co-incubated with B16F10 cells for investigating the effects of cell imaging.The result showed that non-conjugated Pdots were hard to adhere to the cell membrane or enter into the cell,while the Pdots-SA can easily adhere to the cells membrane and well labelling the cell effectively.Thus,Pdots can be effectively applied to cell labeling and imaging applications.Since the wavelength of red light penetrates deeper into the depth of tissues,we further chose Pdots with longest wavelength(PFBT/PF-DBT5)to investigate its biological effects.2.The study on reproductive toxicity effect of PFBT/PF-DBT5.The cumulative dosages of 175.0 ?g per mouse and 87.5 ?g per mouse of PFBT/PF-DBT5 were tail intravenously into the reproductive model female mice of treated groups in the first two pregnant weeks,while the mice of untreated group were tail intravenously phosphate buffer sline(PBS)instead.14 days later,we compared the body weight changes,organ efficient,female hormones level as well as the embryo relative indexes to those of untreated group for investigating the distribution and potential toxic effects of PFBT/PF-DBT5 in maternal mice.The results shown that,PFBT/PF-DBT5 mainly distributed in the liver and spleen of maternal mice,but there has no significant difference was found between treated groups and untreated group(n=6)in the parameters of body weight change,organ efficient and female hormones.Few PFBT/PF-DBT5 were found existed in amniotic fluid but did no damage on the growth and development of embryo.All the above results illustrated that Pdots can be effectively applied in specific cell labeling.In the investigation of in vivo biological effects,most of the PFBT/PF-DBT5 distributed in liver and spleen and few PFBT/PF-DBT5 can be found in the amniotic fluid,but no influence was done on the physiological indexes of maternal mice and the development of embryo.This indicated that,Pdot can be effectively applied in biomedical applications with good biocompatibility,which provides a valuable reference for the future clinical application of PFBT/PF-DBT5 in biomedical area.