Controllable Preparation Of Carbon Dots And Their Interaction With DNA And Protein

Carbon dots(CDs)is an attracted considerable attention star carbon-base nanomaterials with many potential applications.Conventional semiconductor quantum dots,organic fluorescent dyes,and the molecular nanomaterials due to their potential toxicity,low quantum yield,photobleaching,water soluble and preparation of shortcomings such as complicated process,influence their practical application,and carbon dots because of its low toxicity,resistance to photobleaching as well as the advantages of simple preparation,is widely used in nanobiomedical.In this paper,CDs were synthesized from bottom-up by means of water-phase reflux and hydrothermal control,and the CDs with relatively high quantum yield were synthesized by emiting yellow-green fluorescence.On this basis,the mechanism of the interaction between the CDs emiting yellow-green fluorescence and calf thymus DNA was studied at the molecular level,and the possibility of using the CDs as fluorescent probes for nucleic acids was discussed.The interaction between different CDs and proteins was systematically studied to understand the mechanism of interaction between CDs and proteins at the molecular level and the possible difference caused by the interaction between different CDs and proteins.This paper is mainly included five parts:Chapter one,the preparation methods,properties,characterization methods and biological applications of CDs are systematically introduced.The research progress and methods of the interaction between CDs and biomacromolecules are introduced.This paper summarizes the research background,research ideas,research significance and main innovation points.Chapter two focuses on the controllable preparation of CDs.In this chapter,TEM,quantum yield,fluorescence lifetime,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and infrared(FITR)were used to characterize the CDs synthesized by water phase reflux.At the same time,three different CDs were synthesized by hydrothermal method,characterized by TEM,XPS,FITR,quantum yield,UV-vis and flurescence,etc.,and the differences in CDs properties caused by differences in carbon sources were further compared.Chapter three,various spectral methods such as UV-vis spectroscopy,fluorescence spectroscopy,circular dichroism spectroscopy,infrared spectroscopy and fluorescence lifetime,as well as electrochemical methods,are used to discuss the interaction between CDs and ctDNA.The results showed that the mode of action between CDs and ctDNA was insertion,and further demonstrated the feasibility of CDs as an insertion type DNA fluorescent probe.Chapter four,the interaction between different CDs and proteins was studied.The microscopic mechanism,binding constants and main forces of interaction are studied.The effects of CDs on protein conformation were studied by using a variety of spectra.The specific bingding sites of different CDs and proteins were studied through site competition.At the same time,the reliability of experimental results is further verified theoretically by molecular docking technology.In addition,a series of parameters of the interaction between CDs and protein were studied by electrochemical method,and the electron transfer mechanism of the interaction was discussed.