The Application Of Fluorescence Resonance Energy Transfer System Based On Quantum Dots

Nowadays, quantum dots (QDs), a kind of semiconductor nanoparticles, haveattracted a wide range of attention. They have some unique characters such as sizetunable, narrow emission spectra but broad excitation spectra, strong signal intensity,high photostability, and well biocompatibility. Based on the above advantages, inrecent years, QDs have obtained huge development in many fields, such as drugtesting, cell imaging, virus detection, electron transfer detection and so on. In thispaper, based on the characteristic fluorescent property of QDs, we constructed thefluorescence resonance energy transfer (FRET) system between QDs and otherfluorescent material, while CdTe QDs were treated as the donors in our experiments.According to the fluorescence intensity changes of the acceptors, we could detectmelamine (MB) and arsenic (Ⅲ)(As(Ⅲ)), respectively.In the chapter1, we made a short description of the property of nano-material,the property and application of quantum dots and the mechanism and application ofthe fluorescence resonance energy transfer.In the chapter2, we constructed the FRET system between mercaptopropionicacid (MPA)-capped CdTe quantum dots (QDs) and Rhodamine B (RB) in theenvironment of cetyltrimethylammonium bromide (CTAB). In this system, QDs weretreated as energy donors, while RB was treated as energy acceptor. CTAB was used tomake the distance between the particles of QDs and RB closer to make the efficiencyof FRET system occur. We optimized some important factors which would affect theefficiency of FRET system. Under the optimized experimental conditions, MB couldbe detected based on the fluorescence intensity changes of RB in the FRET system.The proposed method was applied to the determination of MB in milk samples withsatisfactory results.In the chapter3, a sensitive and selective As(Ⅲ) detection method based onFRET system between MPA-capped CdTe QDs and Rhodamine6G (R6G) was developed. In this system, QDs were treated as energy donors, while R6G was treatedas energy acceptor. Glutathione (GSH) could attach to the surface of QDs to decreasethe efficiency of FRET, and As(Ⅲ) could combine to GSH to remove the GSH fromQDs to recover the efficiency of FRET, and As(Ⅲ) could be detected based on thefluorescence intensity changes of R6G in the FRET system. The possible mechanismwas discussed. We got a satisfactory result for the As(Ⅲ) detection in the samples oflake water.