Construction Of Cyclooxygenase-2-Targeting Fluorescent Carbon Dots And Their Golgi Apparatus-Targeting Imaging

The Golgi apparatus is an important organelle responsible for transporting proteins in cells.The rupture and abnormal membrane transport of the Golgi apparatus may lead to a variety of diseases and disorders.Therefore,visualization research is of great significance for the realtime monitoring of the Golgi apparatus.Carbon dots(CDs)are emerging zero-dimensional carbon nanomaterials,which have great application potential in the field of biological imaging owing to their advantages of easy modification,low toxicity,and excellent luminescence performance.It is a research hotspot in the field of materials science.At present,in order to solve problems including the blue-green emission of Golgi apparatus-targeting CDs is not conducive to tissue penetration,the synthesis process needs to be simplified,and the targeting mechanism needs to be further developed.This thesis aims at exploring a simple reaction system for preparing long-wavelength Golgi apparatus-targeting CDs based on surface functionalization of benzene sulfonamide and ligand-receptor active targeting strategy with a clear mechanism by the one-step solvothermal method.Moreover,the influence of CDs structure on Golgi apparatus-targeting performance is systematically studied.The main research content and results are as follows:(1)Preparation and application of orange-emission Golgi apparatus-targeting CDs based on benzene sulfonamide for Golgi apparatus-targeting imaging.Aiming at preparing long wavelength-emission Golgi apparatus-targeting CDs,orange-emission Golgi apparatustargeting CDs(GTCDs)were prepared by the one-step solvothermal method at 180 ℃ for 8 h using p-phenylenediamine and benzene sulfonamide as precursors and anhydrous methanol as solvent.As-prepared GTCDs are quasi-spherical,with average particle size of 3.36 nm,graphitized structure,maximum emission wavelength of 612 nm,low cytotoxicity,24-h metabolic time,and good photostability.GTCDs can be used for rapid imaging after their addition and have the ability to accurately locate Golgi apparatus(average Pearson’s colocalization coefficient=0.92).Control experiment shows that when benzene sulfonamide moieties were replaced by benzenesulfonate moieties on the surface of GTCDs,the targeting ability was greatly reduced(average Pearson’s co-localization coefficient=0.66).Combined with the simulation results,these results indicate that the targeting mechanism of GTCDs is the specific receptor-ligand binding between cyclooxygenase-2 and benzene sulfonamide.(2)Preparation and application of red-emission Golgi apparatus-targeting CDs based on Nile blue for Golgi apparatus-targeting imaging.Aiming at further promoting the red shift of the emission wavelength of Golgi apparatus-targeting CDs,red-emission Golgi apparatus-targeting CDs(RGCDs)were prepared by one-step solvothermal method at 190 ℃for 12 h using Nile blue as the precursor,benzene sulfonamide as the targeting recognition unit,and the mixture of deionized water and ethanol as mixed solvent.On the basis of the design strategies of receptor-ligand specific binding and larger conjugated structure,as-prepared RGCDs are quasi-spherical,with average particle size of 2.34 nm,maximum emission wavelength of 648 nm,and low cytotoxicity.RGCDs can be used for Golgi apparatus-targeting imaging(average Pearson’s co-localization coefficient=0.87),which confirms that receptorligand specific binding can be used to design Golgi apparatus-targeting CDs.