The Study On The Fluorescent Carbon Dots And The Application Of Bioimaging And Sensor Detection

Fluorescent nanomaterials including semiconductor nanodots,metal nanoparticles and carbon nanomaterials have a wide range of applications in the field of biological analysis.Because of the shortcomings in cytotoxic biocompatibility of semiconductor quantum dots and metal nanoparticles the carbon nanomaterials have gradually become popular materials in the field of biological analysis.Carbon nanomaterials mainly include carbon nanotubes,graphene,fullerenes and carbon dots,among which carbon dots have attracted attention in the family of carbon nanomaterials due to their good water solubility,low toxicity biocompatibility,and easy synthesis.It is a spherical discrete particle with a diameter of less than10 nm which has nanoscale ultracompactness,excellent photoluminescence,excellent electron transfer ability and multifunctional surface properties,and shows great potential in cell imaging,biosensing,targeted drug delivery and other fields.In this paper,a variety of carbon dots with different properties were synthesized using chemical reagents and green materials as carbon sources.They had been successfully used for the detection of Hg²⁺,Bi³⁺,glutathione and dopamine hydrochloride.Some carbon dots could also be used for cell imaging and mouse imaging.The specific work was as follows:(1)There was a new method for the detection of Hg²⁺and glutathione using carbon dots as fluorescent sensors.The carbon dots we synthesized had the advantages of simple operation and low cost and high fluorescence quantum yield of 22.79%.As the reaction between Hg²⁺and glutathione,the carbon dots were released and the fluorescence was turned on when the glutathione was added.According to this,we used carbon dots as fluorescent sensors for the detection of Hg²⁺and glutathione.(2)Carbon dots with smaller particle size were synthesized by secondary hydrothermal method using ammonium citrate and ethylene diamine as carbon sources.Compared with carbon dots synthesized by primary hydrothermal method,they had more hydroxyl groups on the surface,longer emission wavelength and high quantum yield of 66.41%.It could selectively detect dopamine hydrochloride and had been successfully used to detect dopamine hydrochloride in tumor cells.In addition,the carbon dots had also been successfully used for multicolor cell imaging and C57 mouse imaging.(3)Carbon dots were synthesized by one-pot hydrothermal method using L-methionine and ethylene diamine as precursors.The synthesized carbon dots exhibited good luminescent properties with the optimal excitation wavelength of 380 nm,the optimal emission w avelength of 454 nm,and ultraviolet absorption at200-450 nm.The fluorescence performance of them was stable and only sensitive to Bi³⁺and the fluorescence intensity of carbon dots had a good linear relationship with the concentration of Bi³⁺within0-30?M,which could be used to detect Bi³⁺,with a detection limit of 47.6 n M.(4)The carbon dots with good luminescent properties were synthesized by one-pot hydrothermal method using leaves of Paper Mulberry,which method was green,environmentally friendly,low cost,simple synthesis process and convenient operation.And the synthesized carbon dots had superior luminescence performance,which conformed to the concept of green environmental protection and sustainable development.And the synthesized carbon dots had good selectivity for Bi³⁺and good linear relationship between the[Bi³⁺]at 0-120?M,which could be used to detect Bi³⁺,with a detection limit of2.0?M.