Preparation method for carbon quantum dot with high fluorescence quantum yield and application of carbon quantum dot in cell imaging

Abstract

The invention relates to a preparation method for a carbon quantum dot fluorescent probe used for detection of the concentration of nitric oxide in organisms. The carbon quantum dot is a powdery solidwith excellent water solubility, is synthesized from citric acid and L-cysteine through a microwave-assisted method, and has extremely high quantum yield which is up to 85%. The preparation method for the carbon quantum dot comprises the following steps: 1) dispersing and dissolving the citric acid and the L-cysteine in deionized water; 2) carrying out stirring and ultrasonic dispersion, and allowing the citric acid and the L-cysteine to be uniformly dispersed in a solution; 3) transferring a mixed solution into a microwave oven, and carrying out heating for 2 to 8 min; 4) carrying out cooling to a room temperature, adding water, and carrying out dissolving; 5) transferring an obtained solution into a centrifuge, and carrying out centrifuging at a high speed; and 6) subjecting a centrifuged solution to filtering and drying operations so as to prepare the carbon quantum dot. The carbon quantum dot prepared by using the method provided by the invention has the advantages of high fluorescence quantum yield, good chemical stability, photobleaching resistance and biological compatibility, and applicability to detection of the concentration of the nitric oxide in the organisms.

Description

technical field [0001] The invention belongs to the field of nanometer materials, and in particular relates to a preparation method of carbon quantum dots with high fluorescence quantum yield and its application in cell imaging. Background technique [0002] Carbon is one of the earliest elements human beings came into contact with, and it is also one of the most common elements on earth. Amino acids and nucleotides, the basic units of life on earth, come from carbon as the skeleton, and have been highly concerned throughout the development of human science and technology. Carbon atoms have a variety of electron orbits, which can form many substances with different structural properties, so there are many allotropes of carbon in nature, such as diamond, graphite, graphene, carbon nanotubes, etc. Carbon quantum dots were accidentally discovered by Xu et al. in the purification of single-layer carbon nanotubes in 2004, which triggered a new wave of research on fluorescent nan...

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Problems solved by technology

[0006] However, the quantum yields of currently synthesized carbon quantum dots are relatively low, such as: the quantum yield of yellow quantum dots synthesized by Li et al. is 11.7%, even after sodium borohydride reduction, the quantum yield reaches 22.9%; After the quantum dots were connected to alkaneamides through chemical reactions, the quantum yield increased from 0.02% to 13%; Tesuka et al. modified carbon quantum dots with amino groups and the yield reached more than 40%. In addition, there are many different types of synthetic carbon quantum dots, but they are nowhere near the quantum yield one would expect

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