The Synthesis Of Carbon Quantum Dots Fluorescent Probe And Its Application For ONOO^- And H₂S Detection In Biological System

CDs not only have the traditional semiconductor quantum dots like excellent optical performance,but alao have no light flashing,regulated emission wavelength and excitation wavelength,good biological compatibility and low toxicity etc advantages.Carbon dots have important application value in biological imaging,biosensors,fluorescent probe biological detection,medical diagnosis,metal cation and anion analysis and optoelectronic devices.An environmental-friendly,low-cost and high fluorescent hydrothermal method was developed for preparation of water-soluble fluorescent CDs with o-phenylenediamine as carbon source.In this dissertation,we focus on the research of some key questions related to surface chemical modification,functional composites effects of CDs as fluorescent probe to detection ONOO^-,H₂S.The concrete work completed in this paper was summarized as follows:（1）We constructed a mitochondria-targetable fluorescent Carbon dots probe（CDs-TPP）based on triphenylphosphonium（TPP）modified fluorescent carbon-dots for the first time detection of ONOO^-.The prepared fluorescent probe CDs-TPP was well-dispersed characterized by TEM（transmission electron microscope）,FT-IR（fourier transform infrared spectroscopy）and XPS（X-ray photoelectron spectroscoy）.We constructed a mitochondria-targetable nanoprobe based on triphenylphosphonium（TPP）modified fluorescent carbon-dots,the probe has a good sensitivity for peroxynitrite（ONOO^-）.The target product fluorescent carbon-dots（CDs-TPP）was confirmed by TEM,FT-IR and XPS.The recognition of CDs-TPP for ONOO^-is highly selective and realizes quantitative detection for it.Moreover,the quenched fluorescence intensity of probe was linearly proportional to the concentration of ONOO^-in the range from 0.2 to 1.0μM and the limit of detectation is up to 13.5 nM.Further,we studied the cellular toxicity,targetable property and cellular imaging of the nanoprobe,which proved the fluorescent probe can be used in intracellular detection for ONOO^-.（2）We constructed a lysosome-targetable nanoprobe（CDs-dopa-morph）based on dopaquinone and morpholine modified fluorescent carbon-dots for the detection of H₂S.The prepared fluorescent probe CDs-dopa-morph was well-dispersed characterized by TEM（transmission electron microscope）,FT-IR（fourier transform infrared spectroscopy）.The recognition of CDs-dopa-morph for H₂S is highly selective and realizes quantitative detection for it.Moreover,the enhanced fluorescence intensity of probe was linearly proportional to the concentration of H₂S n the range from 0 to 0.7μM and the limit of detectation is up to 70 nM.This will open up new opportunities for intracellular detection of H₂S.