Studies On Metal-enhanced Fluorescence Based On Quantum Dot And Nano-particles

With the development of life science, the sample we are studying is more and morecomplex, which makes higher request for the technology of biological detection. We allneed a new method of detection with higher sensitivity to improve the detection efficiency.As a new type of fluorescent markers, quantum dots have many advantages whichconventional fluorescent dyes can not compare, and they have been widely used in thefield of biological detection and analysis in recent years. On the other hand, metalnano-particles are also popular materials in the field of biomedical research andapplication due to their good stability and low toxicity. And they can enhance thefluorescence intensity of QDs in some situation effectively through the effect of plasmonresonance. This thesis mainly focuses on building up a method to enhance thefluorescence intensity of quantum dots based on metal nano-particles and studying itsapplication in biological detection.The main work of the thesis contains coating silica on the surface of gold and silvernano-particles and adjusting the distance between metal nano-particles and quantum dotsby controlling the thickness of silica, the complex nano-particles are composed ofquantum dots and metal nano-particles through electrostatic adsorption and chemicalcoupling; according to the result of the experiment, the fluorescence of quantum dots getsthe maximum enhancement when the thickness of silica is10nm, and its fluorescenceintensity is equal to1.8times of the same amount of quantum dots. The other part of theexperiment contains depositing silver nanoparticles on the surface of glass base whichmodified by APTES, and combining quantum dots and silver nano-particles by DNA,adjusting the distance between silver nano-particles and quantum dots by controlling thelength of DNA. The result of experiment indicates that the fluorescence of quantum dotsgets the maximum enhancement when the length of DNA is11.9nm, and its fluorescence intensity is equal to1.4times of the same amount of quantum dots. The experiments wecarried out are in aqueous solution and on the surface of glass base respectively, thus theresult of the system can be evaluated in different enviroment, so that can make the systemgenerally effective, to meet the requirements of high sensitivity in biological detection.