Studies On The Construction And Application Of Fluorescence Resonance Energy Transfer Systems Based On Quantum Dots

Fluorescence resonance energy transfer (FRET) technology as an efficient "optical molecular ruler" that can be used to measure the distance between 1.0-10.0 nm, has been widely used in the inter-molecular distance and molecular structure determination. Due to the unique optical properties and excellent biocompatibility of QDs, FRET based on QDs has made great progress in macrobiomolecular interaction, nucleic acid detection, biosensors and immune analysis etc., and has become a new direction in FRET. In this paper, FRET systems which constructed by using QDs as energy donor and organic dyes as acceptor were applied to study the interactions between QDs and macrobiomolecules; a FRET system that using QDs as energy donor and acceptor was constructed. The main concents and results are as follows:1. Two kinds of thioglycolic acid and glutathione respectively modified CdTe QDs which fluorescence emission wavelength at around 520nm were synthesized. FRET systems which constructed by using QDs as energy donor and Rhodamine 6G as acceptor were applied to study the interactions between QDs and Bovine serum albumin(BSA). The results show that:the distance between QDs and rhodamine 6G were decreased after BSA interacted with QDs, then the energy transfer efficiency of FRET systems were improved; a mechanism that BSA were directly binding to the surface of QDs by the coordination between its tryptophan residues (-Trp) and the metal was preliminary obtained.2. Thioglycolic acid modified CdTe QDs which fluorescence emission wavelength at 541nm was synthesized. A FRET system which constructed by using QDs as energy donor and Rhodamine B as acceptor was applied to study the interactions between QDs and nucleic acid. The results show that:the fluorescence intensity of QDs changed little, but the energy transfer efficiency of FRET system were did not changing after adding DNA or RNA in QDs solution; and neither pH value nor ionic strength caused changes in the energy transfer efficiency of FRET system; counterevidences infered that the interaction modes between QDs and DNA or RNA is Surface binding.3. Two kinds of glutathione modified CdTe QDs which fluorescence emission wavelength respectively at 532nm and 578nm were synthesized. A FRET system which constructed by using short-wavelength QDs as energy donor and long-wavelength QDs as acceptor were constructed in solution. The results show that:FRET occured between CdTe(G) QDs and CdTe(Y) QDs, and the energy transfer efficiency could be increased with the mole ratio of energy donor on acceptor; pH value caused changes in the energy transfer efficiency of FRET system, but ionic strength did not; CTAB acting as positive chelating linkers caused the aggregation of CdTe QDs, thus improved the energy transfer efficiency of FRET system.This research applied FRET technology to investigate the safety of QDs on macrobiomolecule, constructed a FRET system in solution by using two kinds of QDs with different emission wavelengths, afforded initial work basis to develop new biological probes based on QDs FRET which constructed by using QDs as energy donor and acceptor in the future.