Studies On Preparation,Characterazition And Application Of Fluorescent Carbon Quantum Dots From Natrual Materials

With carbon materials developing,carbon quantum dots as a novel and excellent carbon material have gradually been a hot research.Carbon quantum dots are referred to as carbon dots?CDs?.CDs are quasi-spherical nanoparticles with a particle size of less than 10 nm.Because CDs have excellent optical properties,good solubility,excellent biocompatibility,and nearly no toxicity,they have become a good substitute for semiconductor quantum dots.The concept has opened a new milestone for the exploration of fluorescent quantum dots.In this paper,CDs have been studied from the following two aspects:1.CDs with co doping of phosphorus and nitrogen have been synthesized using apricot kernel via pyrolysis and hydrothermal treatment,providing a green preparation way for the production of CDs without the use of toxic/expensive solvents and starting materials.The prepared CDs exhibit exceptional advantages including excellent biocompatibility,low toxicity,satisfactory chemical stability and high fluorescent quantum yield.Depending on these superior properties,the CDs have been applied in cell imaging and biosensing.Confocal laser scanning of human hepatoma cells?HepG-2?reveals that CDs penetrate the cell wall and enter the cytoplasm,and they emit bright fluorescence,which indicates that they can be used for cell imaging.In addition,the specific selection and high sensitivity of this carbon dots to Fe³⁺in aqueous solution can be used to detect the concentration of Fe³⁺in the cell and realize the function of biosensing.2.Astragalus membranaceus was selected from Chinese herbs and utilized to prepare fluorescent carbon dots by one-step hydrothermal method.Besides,the resulting CDs emit bright blue light under the 365 nm UV lamp excitation.CDs can be applied to Fe³⁺sensing,cell imaging and patterning.In Fe ³⁺sensing,the detection range is 100?M-300?M and its detection limit is 2 nM,so it indicates that it can complete the detection of Fe³⁺.And confocal laser scanning of human hepatoma cells?HepG-2?showed that CDs could enter the cell and emit fluorescence,showing the morphology of the cell.In addition,the carbon dots can also be prepared as a fluorescent ink to make a fluorescent pattern.