Surface Modified Quantum Dots?QDS? Are Used To Detect Viruses And Cu²⁺ In Water

In recent years,due to the unique physical and chemical properties of quantum dots,they have attracted the attention of many scientific researchers.In this paper,using CdTe's excellent photoelectric properties,and then using the principle of energy resonance transfer and the complementary pairing of biological bases,a simple and fast method for virus monitoring in water was constructed.Firstly,by controlling the length of the hydrothermal synthesis reaction,the appropriate wavelength and color quantum dots that can undergo energy resonance transfer are selected.Then quantum dot the surface modification of functionalization of carboxyl is through in the reaction such as thioglycolic acid,by introducing the catalyst of EDC and the NHS will design the capture of DNA on the amino and the combination of quantum dots on the carboxyl,then form the want the biological response of the probe,the last use of biology in the purpose of the principle of complementary base pairing HAV specific DNA sequence is used to detect the specificity and high selectivity.The chemical and physical structures of the biosensor were characterized by transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy and dynamic light scattering.Through a large number of experiments and data show that the established biosensor in rapid detection of anti-interference and fluorescence intensity and material has the advantages of good,also this thesis construct biosensor,at 4 ? in the dark has good optical and fairly stable characteristics.In addition,the constructed qds-fret biological probe provides quantitative detection of the target DNA without the need to separate non-complementary DNA and mismatched DNA from complex samples,indicating that the nanosensor can accurately and effectively distinguish the target DNA and single-base mismatched ribonucleotides in the sequencing system.Under the optimal conditions,from a good linear relationship of 2 10-10 mol/L to 5 10-8 mol/L,and the detection limit of 1.310-11 mol/L,this biosensor has a wide linear range and a very low detection limit for the target DNA detection.Finally,through the actual detection of three water samples,it is also confirmed that the biosensor constructed can be applied to the virus detection and monitoring of actual water bodies,showing its good application potential.Because the fluorescence of CdTe is unstable and has surface defects,this paper also modified the surface of this quantum dot and functionalized it.First USES the surface coated ZnS,administered make the original quantum dots to reduce surface defect,the experimental results showed that after modification of quantum dot fluorescent compared without fluorescence enhancement after modification of quantum dots,through doped manganese element into the quantum dots also found that the modified version of fluorescence has atendency to increase,this is due to surface modification can make up for the defects on the original quantum dots,the resulting optimized its optical properties.It was also found that the fluorescent probe had a good response to copper ions in the solution.By adding different kinds of metal ions and analyzing their fluorescence spectra,it showed that the quantum dots modified by surface functionalization had high selectivity.Under the optimization of experimental conditions,there is a good linear range of 10 umol/L to 600 umol/L for the detection of copper ions,and there is a benign linear relationship in this hybrid system(the correlation coefficient thus obtained is 0.99).By calculating the formula of detection limit,LOD is calculated to be 8.9 umol/L.The experimental data show that the surface modified and manganese doped quantum dots synthesized in this chapter can detect copper ions qualitatively and quantitatively with high efficiency and sensitivity.