Preparation And Performance Study Of Carbon Dot Fluorescence Sensor

Carbon dots?CDs?recently emerges as superior and universal fluorophores because of their unique combination of a number of key merits,including excellent photostability,small size,biocompatibility,highly tunable photoluminescence property,electrochemiluminescence,ease to be functionalized with biomolecules,and chemical inertness.CDs as chemical sensors have been applied to detect heavy metal ions and organics.The main contents are as follows:1.Biomass is regarded as an excellent candidate for the preparation of heteroatom-doped carbon nanomaterials.We have developed a simple and facile one-pot synthesis of nitrogen and sulfur codoped fluorescent carbon dots from pigeon feathers,egg and manure via the pyrolysis carbonization method.The as-prepared four PCDs have high fluorescence quantum yield about 24.87%?PCDs-f?,17.48%?PCDs-w?,16.34%?PCDs-y?,33.50%?PCDs-m?,respectively.We found that the preparation of PCDs-m with pigeon manure has no favourable selectively with heavy metal iorns.However,other PCDs exhibit highly sensitive and selective detection behavior of Hg²⁺/Fe₃₊ ions with alow detection limit of 10.3 and 60.9nM.They were applied to imaging ofhuman umbilical vein endothelial cells,showing low cytotoxicity and good biocompatibility.2.Nitrogen and boron co-doped carbon dots?BCNDsl-3?were prepared from three kinds of borate via a facile hydrothermal method.The as-prepared BCNDs possess good water dispersibility and high fluorescent quantum yield of 29.01%,51.42%,68.28%,respectively.Subsequently,these BCNDs were exploited as excellent Hg²⁺ ion and 2,4,6-trinitrophenol?TNP?probe.The efficient selective detection of Hg²⁺can be attributed to non-radiative electron/hole recombination annihilation through an effective electron transfer process and the detection of TNP can be attributed to the fluorescence resonance energy transfer process.The results show that the BCNDs2 is the most sensitive fluorescence probe for Hg²⁺ ions and TNP detection3.CDs were covalently linked to 4-carboxyphenylboronic acid molecules to form the 4-carboxyphenylboronic acid molecules-functionalized CDs?CPBA-CDs?.CPBA-CDs could covalently bridge the catechol with the vicinal diol structures and would cause the fluorescence quenching via the surface quenching states induced mechanism.The fluorescent response for catechol detection was in the linear ranges from 0.1 to 56?M with the detection limit of 115 nM.4.A novel fluorescent sensor based on CDs was synthesized for directdetermination of glutathione?GSH?,which bromoacetyl bromide was functionalized CDs?CDs-Br?sensing system for the first time.The bromoacetyl bromide functional groups?halogen moiety?can quench the fluorescence of CDs,which were substituted by the-SH group,could lead to a significant fluorescence increase of CDs-Br via the halogen substitution cyclization.Under optimum conditions,the probe has a good selectivity for GSH over other various biologically relevant species and even two other similar biothiols?Cys/Hcy?and could image GSH in living cells.