Synthesis And Biological Effects Of Water-soluble Carbon Quantum Dots

In this study,the classical hydrothermal and microwave methods were used to synthesize three kinds of carbon quantum dots(CQDs).The use of these three CQDs for biological toxicity experiments is representative and can provide a certain scientific basis for the biological toxicity of CQDs.In addition,red carbon quantum dots have unique fluorescence properties compared to common carbon quantum dots of other colors,can avoid interference from background light,and have potential applications in biomarking and medical treatment in the future.Therefore,this article focuses on the research of red light carbon quantum dots(R-CQDs),and two C-dots of green light(GCQDs)and blue light(B-CQDs)as controls,from lower organisms to higher organisms.Research on the impact of biological growth,there is currently no unified measurement standard for the biological toxicity of CQDs,so this article draws on the broad bean micronucleus experiment in order to provide a reference standard for evaluating the toxicity of CQDs.In the experiment,the higher biological broad bean rice was treated with different concentrations of R-CQDs,G-CQDs,and B-CQDs to determine the physiological and biochemical indexes.In the preliminary experiment of lower organisms,it is found that the preparation of G-CQDs and B-CQDs is extremely sensitive to E.coli and yeast,and the experimental operation is difficult.Therefore,the research on lower organisms in the experiment only uses R-CQDs for antibacterial performance.Detection and discussion of antibacterial mechanism.It is expected to provide scientific research basis for evaluating the biological effects of CQDs.The research conclusions are as follows:1.Different concentrations of R-CQDs have different effects on the growth and activity of E.coli and yeast: as the concentration of R-CQDs increases,the activity of the two bacteria decreases.When the concentration reaches 20 mg/L,E.coli and yeast basically The mechanism of death and apoptosis of E.coli and yeast is that CQDs cause the integrity of the cell membrane of the bacteria to be destroyed,causing intracellular material to flow out,and the physiological functions of E.coli and yeast are affected.It shows that E.coli and yeast are sensitive to CQDs and inhibit the growth of the two bacteria.2.R-CQDs,G-CQDs,B-CQDs three CQDs treatment of broad bean root tip cells induce chromosomal aberrations to produce micronuclei,and the number of micronuclei is proportional to the dose of the poison,and the micronucleus rate increases with the treatment time.However,it is inferred that the longer the treatment time of CQDs on cells,the more CQDs accumulate in the cells in the body,and the stronger the toxicity,indicating that CQDs have certain biological toxicity.3.Three CQDs of R-CQDs,G-CQDs,and B-CQDs were used to treat rice.The results showed that as the concentration of R-CQDs and G-CQDs increased,the inhibitory effect on the growth of rice seedlings became more and more significant.When the concentration is 1000 mg/L,rice root length,plant height,dry weight and fresh weight are reduced by about 40% compared with the control group,which inhibits the growth of rice seedlings.As the concentration increases,rice root length and plant weight The high,dry weight and fresh weight are about 27% higher than the control group,which obviously promotes the growth of rice seedlings.The roots and leaves of rice were pressed in vivo,and the fluorescence microscope was used to observe that CQDs were absorbed by the rice roots and transported from the roots to the leaves of the rice.In addition,the study on the mechanism of the toxic effect of rice was carried out,and the antioxidant indicators in rice were determined.The results showed that the enzyme activities of CAT and POD and the content of malondialdehyde in rice treated with 1000mg/LR-CQDs and G-CQDs increased to varying degrees.It shows that the treatment of R-CQDs and G-CQDs caused oxidative damage to rice,but the activity of CAT and POD enzymes in rice treated with B-CQDs did not change significantly,and there was no difference in the content of malondialdehyde.It shows that B-CQDs has less oxidative damage to rice.