Green Synthesis Of Nitrogen-Doped Graphene Quantum Dots And Their Interaction With Biological Macromolecules

Graphene quantum dots(GQDs)are a new type of fluorescent material that have been discovered after carbon nanomaterials such as two-dimensional graphene,onedimensional carbon nanotubes,and zero-dimensional fullerene have come out.In this thesis,GQDs are selected as the research object of synthetic preparation.N-doped GQDs with different N source forms are synthesized with good biocompatibility.The physical and chemical properties of N-doped GQDs are studied.The impact of heterogeneous GQDs on biocompatibility.Molecular simulation methods are used to predict the specific site where GQDs bind to biological macromolecules.The main research contents of the paper are as follows:1.Two different N-source N-doped GQDs were first synthesized by hydrothermal synthesis in one step.Firstly,glycine and citric acid were used for preliminary synthesis,and then Na OH was introduced in the experiment to enhance the fluorescence performance of the product.Then adjust the reaction time,reaction temperature,and citric acid: Na OH: glycine reaction ratio.N-doped GQDs with particle diameters of 3-8 nm and optimal fluorescence excitation and emission wavelengths at 340 nm and 450 nm were obtained.Subsequently,the N source was replaced by an experiment,and a binaphthol derivative was used as the N source.The GQDs synthesized by this method basically have the former advantages.The positions of the excitation and emission peaks in the fluorescence spectrum are at 340 nm and 430 nm,respectively,and the surface groups are more Rich,greatly improving the application performance and scope of this quantum dot.2.The molecular simulation,ultraviolet spectroscopy,fluorescence spectroscopy,circular dichroism spectroscopy,electrochemical methods,and gel electrophoresis were used to systematically investigate the effects of GQDs from two different N sources on ct DNA.The experimental results showed that glycine was used as the product of N source has a slight effect on ct DNA,but there is a relatively obvious disturbance to ct DNA when the product using binaphthol derivative as N source interacts with ct DNA.At the same time,in the presence of metal ions,the product using binaphthol derivative as the N source showed excellent performance.The molecular effects of intercalation and groove modes on the conformation of N-doped GQDs and DNA were compared by molecular simulation.Under ideal conditions,the binding mode of N-doped GQDs and DNA is more likely to be intercalation,and hydrogen exists between the molecules.3.The effects of GQDs of two different N sources on HSA were investigated by molecular simulation,ultraviolet spectroscopy,fluorescence spectroscopy,circular dichroism,and gel electrophoresis.The effect of HSA is relatively small,but there is a relatively obvious interaction with HSA when the product using binaphthol derivatives as the N source interacts with HSA.Molecular simulation results show that GQDs with both N and O elements in the ideal state interact with HSA molecules in the ideal state,and tend to bind to the position III of HSA,which is conducive to forming hydrogen bonds with amino acid residues in HSA And the molecule is flexible,and can better affinity to the HSA environment.