Synthesis Of New Carbon Dots And Their Applications In Water Sample Analysis And Biological Imaging

Carbon dots(CDs)are an emerging fluorescent nanomaterial that comprise microspherical,highly monodispersed particles with sizes below 10 nm.It possess chemical stability,tunable photoluminescence and the excellent biosafety.By virtue of their excellent properties,CDs have exhibited promising performances in drug carriers,sensing,biological imaging and catalysis.Generally speaking,the preparation methods of CDs include “ top-down ” and “ bottom-up ”.The former is mainly electrochemical synthesis,laser ablation,discharge synthesis and direct carbonation.The latter primarily consist of pyrolysis,microwave-assisted procedures,wet oxidation and hydrothermal synthesis.Chapter 1: A brief review of CDs and their synthesis methods,properties,methods of improve optical performance and applications.And the background of the topic and the main research contents are also explained.Chapter 2: In this work,the N-CDs were prepared by pyrolyzing edetic acid and acrylamide.The as-prepared CDs were performed using TEM,FT-IR,UV-vis and FL et al.The N-CDs possess small size,excellent biosafety,remarkable biocompatibility and tunability.Due to the inner filter effect,the fluorescence of N-CDs could be effectively quenched by picric acid(PA).In the range of 0.1-30 ?M,the fluorescence intensity of N-CDs exhibit a good linear response for PA and the detection limit was 46 n M.And this method has successfully applied for accurate analysis of PA in Fenhe river samples.Chapter 3: In this work,the fluorescent N-CDs were hydrothermal prepared via using o-phenylenediamine and dicyandiamine.The as-prepared CDs were performed using TEM,FT-IR,Raman,XPS,UV-vis and FL et al.The N-CDs are uniformly dispersed spherical nanoparticles with favorable solubility,superior photoluminescence and photobleaching resistance.The fluorescence intensity of N-CDs is linearly quenched by 4-nitrophenol(4-NP)over a concentration range of 0.1-39 ?M,corresponding to a detection limit of 50 n M.Based on this phenomenon,a 4-NP-detection method is established and applied to real samples analysis.Importantly,the N-CDs were further applied for biological imaging in O.laustris based on its less toxicity,small size and excellent biocompatibility.Chapter 4: In this work,N-CDs were synthesized through hydrothermal-assisted heating of o-phenylenediamine and urea.The as-prepared CDs were characterized using TEM,FT-IR,XPS,UV-vis and FL et al.The N-CDs possess low toxicity,high biocompatibility,photobleaching resistance and multiple functional groups.Based on the formation of a stable non-fluorescent ground-state complex,the fluorescence intensity of N-CDs is linearly quenched by Co(?)in the range of 0.1-30 ?M and the detection limit as low as 52 n M.The method has been successfully applied to the precise analysis of Co(?)in real samples.Furthermore,the N-CDs satisfactorily serve as a staining probe for the in vivo bioimaging of zebrafish.In this paper,three kinds of functional fluorescent CDs were obtained through green synthesis using cheap,readily available and low-toxic raw materials.The determination of PA,4-NP and Co(?)content in actual samples was achieved.At the same time,CDs were further used for biological imaging due to their low toxicity,small size and good biocompatibility,and have potential application values.