Ratiometric Fluorescence Probe For Intracellular Cu²⁺ Imaging Based On The Nanohybrid Of Quantum Dots And Carbon

Heavy metal ions(Cu²⁺) has become more and more seriously to affect on biological and environment, the influence of Cu²⁺ has an irreplaceable role in physiology and nutrition, but excessive intake of copper will cause some diseases in the body of animals and plants. At present, the relevant Cu²⁺ detection method has become increasingly rich, all kinds of classical detection methods, such as spectrophotometry, atomic absorption spectrometry, electrochemical method,chromatography, mass spectrometry, etc can realize quantitatively and sensitively detection, but the instruments of these methods are expensive and inconvenient to carry, and the operation process of the trial is tedious. So these kinds of classical detection methods are not suitable for rapid real-time detection. In view of this,exploring a simple, rapid and sensitive method for the detection of Cu²⁺ is very important. Recently, a lot of fluorescent probes used for quantitative detection of Cu²⁺were designed. In order to get better results, this thesis designs a kind of double-emission ratio fluorescence probe, its performance of the detection, and some relative studies will presentation as follows:（1） In order to explore the sensitivity and selectivity of this probe, the synthesized CdTe/CdS core-shell typed quantum dots and amine functionalization carbon dots will be characterized by SEM, HRTEM, FL, DLS, pH meter etc. The sensitivity choice of quantum dots and carbon dots to Cu²⁺ and their biological toxicity will be explored also. We can get the results of the biological nontoxicity of the amino-functionalized carbon dots and the lower fluorescence quenching response of carbon dots for Cu²⁺. So the carbon dots are more suitable to be used as a reference signal for this fluorescent probe, while CdTe/CdS core-shell typed of quantum dots is selectivity and sensitively to the analysis of Cu²⁺, which is suitable and used as a fluorescence signal tag.（2） In the detection of real biological samples, the biocompatibility is the problem to conquer. Using CdTe/CdS core-shell quantum dots which is good at selectivity for Cu²⁺ modification onto the surface of silica microspheres, and due tothe grid of the silica microspheres is light transparent, so this kind of design can largely reduce the loss of fluorescence intensity of the fluorescence signal tags. Using the low biological toxicity of carbon dots sealed package on the surface of the probe,not only increased the loading efficiency of the outermost carbon onto the surface of the probe, but also reduce the biological toxicity of the probe. Using this probe to the detection of Cu²⁺ in HeLa cells can realize the fluorescence intracellular imaging of Cu²⁺, which should thanks to the low toxicity of the probe, HeLa cell can absorb enough of the probe. The results also reveal the ultrasensitive analysis of the probe even though exposure to other interference. It must be say that the realization of fluorescence intracellular Cu²⁺ imaging of this probe has opened up new possibilities for in vivo detection.