Synthesis Of Novel Doped Carbon Dots And Its Application In Analysis And Cellular Imaging

Carbon dots,as a new kind of fluorescent nanoparticles,have attracted much attention due to its many advantages,such as good fluorescence stability,low toxicity,high biocompatibility and stable chemical properties.In order to explore carbon dots with some special functions,the researchers have done a lot of work to synthesize novel carbon dots and study their application.Doping with heteroatom is a simple and effective method to improve the properties of carbon dots.Nowadays,carbon dots have been used in many fields such as bioimaging,biosensor etc.However,it is very important to explore novel carbon dots for specific applications and understand the mechanism of photoluminescence,and broaden its application fields.In this paper,different organic molecules are used as precursors to synthesize different double-doped carbon dots,which are used for ion detection and fluorescence imaging.The details are as follows:1.Multifunctional B,N co-doped carbon dots?B/N-C-dots?were synthesized from a facile hydrothermal treatment of branched polyethylenimine and 4-formylphenylboronic acid.The obtained B/N-C-dots had a very narrow size distribution and showed excitation-wavelength-dependent photoluminescence property with a high fluorescence quantum yield?QY?of 15.85%.The B/N-C-dots showed temperature and pH?3-13?dual responses.Additionally,the B/N-C-dots showed a good sensitivity and selectivity to Fe³⁺ with a detection limit of 1.62 ?M.What's more,the as-prepared B/N-C-dots exhibited low toxicity and good biocompatibility,and could be used for cell imaging.Considering these good properties,the obtained B/N-C-dots have good potential for temperature,pH and ion sensors and cellular imaging.2.Nitrogen and sulfur co-doped carbon dots?N,S/C-dots?were prepared via onepot hydrothermal treatment of citric acid and cystamine dihydrochloride.The asprepared N,S/C-dots exhibited excellent excitation-wavelength-independent photoluminescence property with a high fluorescence quantum yield?QY?of 39.7%.The N,S/C-dots were well-dispersed in aqueous solution and showed good photoluminescence stabilities in different pH and temperature without any surface modification.Additionally,the fluorescence of N,S/C-dots can be quenched based on inner filter effect?IFE?upon the addition of Cr?VI?and showed good selectivity and sensitivity to Cr?VI?.What's more,in comparison with other quantum dots and organic dyes,these N,S/C-dots were much more eco-friendly and can be used for multicolor bioimaging.