Synthesis And Characterization Of Naphthalene Bisimides-Incorporated Water-Soluble And Fluorescent Polyurethane For Living-Cell Imaging

The Naphthalene diimides have gained great attention because of their good photoehemical and photophsical properties.Thay have large potential application market in various fields,so it was a chance and a challenge for us to develop functional derivatives of naphthalimide with tailorable properties.The reactive precursor of N,N'-Bis?2-[2-hydroxyethoxy]ethyl?-1,4,5,8-Naphthalenetetracarboxylic acid bisimide?NAP-OH?was first synthesized by imidization using 1,4,5,8-Naphthalenetetracarboxylic dianhydride and diglycolamine as initial materials.Then we designed two types of polymer fluorescent dyes based on novel NAP-OH,and discussed its related applications.1.A series of naphthalene diimides-incorporated polyurethanes?HDI-NAP-PEG?were synthesized from poly?ethylene glycol??PEG?,NAP-OH and hexamethylene diisocyanate?HDI?using the facile and well-established method for common polyurethane preparation.The chemical component and molecular weight of the HDI-NAP-PEG copolymers were characterized by ¹H NMR,FTIR,and gel permeation chromatography?GPC?,respectively.The photophysical and photochemical characteristics in chloroform and aqueous were studied by ultraviolet ray absorption spectra?UV-Vis?and fluorescence emission spectra?FL?.The results show that,copolymers were not only soluble in polar-organic solvent but also can be easily dissolved in water,and showed good fluorescent properties.The HDI-NAP-PEG can be used as an efficient cell bio-dye for cell labeling and the cells emitted bright-green fluorescence from their cytoplasm.With the strong fluorescence in water and good cell labeling properties,the developed HDI-NAP-PEG might possess more potential in bioimaging.2 Based on the previous work,HDI-NAP-PEG with a hydroxyl end group?HDI-NAPPEG-OH?was successfully synthesized by reducing the amount of HDI.The amphiphilic HDINAP-PEG-poly??-caprolactone??HDI-NAP-PEG-b-PCL?was prepared by ring-opening polymerization of ?-caprolactone??-CL?using HDI-NAP-PEG-OH as macroinitiator and Sn?Oct?₂ as catalyst.The molecular weight and chemical structure were investigated by ¹H NMR and GPC.The results confirmed that the product has the proposed tructure.Then the HDINAP-PEG-b-PCL Nanoparticles was prepared by precipitation / solvent evaporation method.The sizes and polydispersity of nanoparticles were determined by Dynamic light scattering?DLS?.The results display an average particle size of 219 nm and the size distribution was narrow.Besides,the morphology of the Nanoparticles was mainly spherical determined by scanning electron microscope?SEM?.The Nanoparticles has strong fluorescence in water and will be an effective carrier for cell labeling and drug delivery.