Studies On Functionalized Quantum Dots Of Its Applications In Biologic Analysis

Semiconductor quantum dots materials with unique optical and electrical properties have been widely used.With the development of synthesis and modification technology,semiconductor nanoparticles have tremendous application potential in many research fields,such as sensor, photoluminescence,electroluminescence and biologic probe.The preparation of highly luminescent water-soluble quantum dots has been investigated widely during the past decade.Compared with conventional organic methods,it is simple and with a low cost and low toxicity.In this thesis,the water-soluble quantum dots were synthesized and modified and used to protein and DNA research.The main work is as follows:(1) L-cysteine modified ZnS nanoparticles with uniformity in size and good dispersancy were synthesized and characterized.UV-Vis spectrometry,fluorescence spectrometry and Attenuated Total Reflectance Fourier Transform Intrared(ATR-FTIR) spectrometry were used to study the interaction of ZnS nanoparticles modified by L-cystemine and Bovine Hemoglobin.The results indicate that the fluorescence of functionalized ZnS nanoparticles was significantly quenched by Bovine Hemoglobin.The affection of functionalized ZnS nanoparticles in the second structure of BHb was also investigated.(2) A novel method for detection of point mutation in DNA based on monobase-coded CdTe nanoprobe using quartz crystal microbalance (QCM) technique has been proposed in this work.Single base-coded CdTe nanoparticles were synthesized and characterized.Gold coated Fe₃O₄ magnetic nanoparticles were used to immobilize and separate DNA. Magnetic beads modified with point mutation DNA were immobilized onto the electrode surface through an external magnetic field.The hybridization between single-base coded CdTe nanoparticles and mismatched base would aroused the change of QCM frequency. Conquently,correlative information about point mutation could be obtained.This method is demonstrated to be sensitive,simple,repeatable and low-cost and has a great potential for SNP detection.(3) The present study reports a novel method for DNA point mutation detection by hybridization of DNA functioned CdTe nanoparticle probe and detection probe attached on Fe₃O₄/Au magnetic nanoparticles with target DNA strand,using differential pulse anodic stripping voltammetry (DPV) and fluorescence spectra.The application of Fe₃O₄/Au magnetic nanoparticles not only simplifies the experiment enormously owing to readily separation from sample solution,but also enlarges the response and consequently improves the sensitivity largely.The results obtained have revealed that this approach is feasible,effortless and ingenious.