Synthesis And Application Of Multiple Photoswitchable Fluorescent Polymeric Materials

At present,the photoswitchable system with color and multi-state fluorescence changes is the key to the realization of advanced multi-level information storage,and its application potential has far exceeded that of the monochromatic fluorescent system.Due to nanoparticles have high water dispersibility and large specific surface area,the hydrophobic core or surface can be loaded or connected to specific functional molecules such as fluorescent dyes,so the fluorescence intensity is much higher than that of individual molecules,thus providing brighter and more reliable fluorescence signal.Based on this,in this thesis,two different multi-color fluorescent systems were constructed based on different principles,and their performance was systematically studied,and they were applied to the fields of targeting cancer cells,information encryption,and storage.The specific research content is as follows:(1)Diarylethylene 3,3'-(perfluorocyclopent-1-ene-1,2-diyl)bis(2-ethylbenzo [b]thiophene-1,1-Dioxide)(DBTEO)and the red fluorescent dye5,10,15,20-tetraphenylporphyrin(TPP)with large Stokes shift were simply combined to PMMA by one-step miniemulsion polymerization method.The preparation of nanoparticles(ZDPNs)with complete color-specific signal and zero crosstalk have been realized.Through a reasonable ratio design,the nanoparticles showed high contrast and zero crosstalk dual-color fluorescence characteristics.We demonstrated their application potential in information encryption and anti-counterfeiting,erasable fluorescent patterns,and dual-color imaging with targeting cancer cells.They were expected to play an important role in information security,data storage and super-resolution biological imaging.(2)Based on the principle of FRET,two molecules with photoswitchable fluorescence characteristics,2-(methacryloyloxy)ethyl 3-(3,3,4,4,5,5-hexafluoro-2-(2-methyl-1,1-dioxybenzo[b]thiophen-3-yl)cyclopenta-1-en-1-yl)-2-methylbenzo [b] thiophen-6-carboxylate 1,1-dioxide(BH)and 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-Indole]-1'-yl)ethyl methacrylate(SPMA)were introduced into polymer nanoparticles.After the alternating irradiation of different ultraviolet light and visible light,the fluorescence of the nanoparticles showed reversible transition between the three states of green,red,and quenching.BH used 254 nm ultraviolet light and 460 nm visible light to irradiate alternately,and the nanoparticles could be reversibly switched between green and quenching.SPMA could be irradiated alternately with 365 nm ultraviolet light and 525 nm visible light,and the nanoparticles could be reversibly switched between red and quenching.At the same time,due to the effect of FRET,SPMA could also regulate the fluorescence of BH.This multi-wavelength regulated nanoparticle realized the reversible regulation of multi-level fluorescence in solutions and films.In addition,the fluorescent polymer nanoparticles system has also been successfully applied to the fields of information multi-level encryption and display.