The Application Of Carbon Dots In Chemiluminescence And Cell Imaging

Carbon dots (CDs) emerged as a new kind of fluorescent carbon nanomaterial, have received much attention due to their high photostability against photobleaching, no blinking, biocompatibility, low toxicity, and environmental friendliness. Therefore, they have been successfully used in bioimaging, catalysis, and sensing. However, compared with quantum dots, the research of Carbon dots is still in its infancy and much of work remain to be solved. We have reported that the fluorescence property of Carbon dots is coordinated by change the surface group of Carbon dots through a simple reduction reaction. Carbon dots with good biocompatibility and small diameter are easy to enter the cell. Therefore, we have investigated the surface group effect on the CL behaviors of Carbon dots, and also used Carbon dots as the carrier import fluorescent dyes in the cell for cell imaging studies. The main research works on this thesis are as follows:(1) The CDs and r-CDs have different surface groups. Herein, we chose CDs and r-CDs as models to establish CDs-KMnO4and r-CDs-KMnO4chemiluminescence (CL) systems and investigate the surface group effect on the CL behaviors of CDs for the first time. In the same conditions, the CL signal of r-CDs-KMnO4was higher than that of CDs-KMnO4. The mechanism of the two CL systems was investigated by UV-vis absorption spectra, fluorescence spectra, CL spectra, and electron paramagnanetic resonance (EPR) spectra. The investigation on the CL properties of the CDs system and the r-CDs system not only gains a better understanding of the relationship of CL behavior and surface groups but also brings a broader prospect for synthesis of CDs with eximious optical properties (good CL property and high PL intensity). Furthermore, the CL of CDs opens up newr opportunities for their potential applications in the analysis technology.(2) The prepared r-CDs can enhance the weak chemiluminescence signal from the reaction of potassium permanganate and sodium bisulfate. The concentrations of potassium permanganate, sodium bisulfate, sulfuric acid and r-CDs were optimized to make the chemiluminescence signal highest. The possible mechanism of the KMnO4-NaHSO3-r-CDs chemiluminescence system was preliminarily studied through UV-vis absorption spectra, fluorescence spectra and CL spectra. The enhancement mechanism of the r-CDs on KMnO4-NaHSO3was supposed to originate from the catalysis of r-CDs, which facilitated the radical generation and electron-transfer processes taking place on the surface of r-CDs.(3) The nano-composite particles were prepared by couping tetramethylrhodamine isothiocyanate (TRITC) and fluorescein isothiocyanate (FITC) with the HCDs, respectively. This method not only can enhance the quantum yield of HCDs, but also can used HCDs as the carrier import fluorescent dyes in the cell. The HCDs and fluorescent dye were combined through chemical bond by analysis of the X-ray photoelectron spectroscopy (XPS) spectra. The maximum emission wavelength was observed for the functionalized HCDs, and note that the maximum emission wavelengths of these compounds were same to the maximum emission wavelengths of the single dyes. The prepared fluorescence composite materials have good water-soluble, biocompatibility and low toxicity. Therefore, the composite materials can be used in cell imaging. Benefitted from their excellent properties, the prepared composite materials have a broad range of desirable application in biological labeling and bioimaging.