Design,Synthesis And Imaging Of Hydrophilic Aggregation-induced Emission Probes With D-?-A Diarylethene Framework

Aggregation-induced emission molecules(AIEgens)have been widely applied due to the merits of AIE character,large Stokes shift,excellent photostability and prominent biocompatibility.Especially,the hydrophilic/water-soluble AIEgens may achieve wash-free fluorescent labeling due to the absence of background fluorescence in the water,which has shown great potential in the field of bioimaging.Diarylethene-type AIEgens is a type of simple,easy-to-synthesize,multifunctional fluorescent molecule.However,the systematic study on diarylethene-type AIEgens is rarely reported,especially the hydrophilic/watersoluble diarylethene-type AIEgens.Besides,the applications of diarylethene-type AIEgens mainly focus on the field of cell imaging.In addition,the conventional organic fluorescent probes show some shortcomings in the application of fluorescence imaging,such as complicated operation,poor signal-to-noise ratio and low resolution.Therefore,relying on the simple Knoevenagel condensation reaction,a series of high-performance AIEgens with diarylethene framework were synthesized by adjusting the type and number of the donor section(D)and acceptor section(A)in the vinyl framework.By adjusting the substituent groups,the hydrophilic/hydrophobic property of the molecules was regulated.The applications of diarylethene-type AIEgens in high-performance cell imaging,fluorescence imaging of A? plaques in brain tissue,fluorescence development of latent fingerprint(LFP)and other fields were expanded.Convenient,efficient and high-resolution fluorescence imaging were achieved based on these high-performance diarylethene-type AIEgens.The main research contents are as follows:(1)The microstructure of A? plaques in mice brain slice is hardly obtained by conventional fluorescence imaging.In view of that the high performance of A? probes diarylethene framework were designed and synthesized.The specific morphology of A? plaques in brain slices of Tg mice were studied in nanoscale by integrating the fluorescence imaging with the super-resolution fluorescence imaging,providing the structure information with optical resolution below 50 nm.It is of great significance to understand its formation mechanism.(2)Water-soluble wash-free A? probes PD-BZ-OH and PD-NA-OH with diarylethene framework were designed and synthesized,in which the hydroxyethyl-pyridine cationic group was introduced as a water-soluble section.Combined with fluorescence micro-optical sectioning tomography(f MOST)system,the 3D distribution of A? plaques in the mouse brain was obtained.A convenient and efficient method for constructing 3D distribution of A? plaques in large sample tissues was created,which overcomed the shortcomings in the existing technology of immunolabeling combined with light-transparent treatment,such as cumbersome,time consuming,high-cost and low detection rate of deep brain region.(3)A series of amphiphilic/water-soluble diarylethene-type AIE small molecules TPA-1OH,TPA-2OH and TPA-3OH with far-red emission were constructed by introducing triphenylamine electron donor group and regulating the number of hydroxyethyl-pyridine cations(1?3)in the molecule.The in-situ wash-free fluorescence imaging of mitochondria and cell nucleus was successfully achieved.Besides,a simple method for preparing far-red fluorescent AIE-Dot with uniform and controllable particle-size was created by the physical penetration reaction of these three amphiphilic/water-soluble AIEgens with hydrogel nanoparticles.(4)Based on the hydrophilic-hydrophobic properties of amphiphilic AIE molecule TPA-1OH,latent fingerprint(LFP)was successfully developed by the safe,convenient and highefficiency method of soaking in or spraying with TPA-1OH aqueous solution(30 ?M).And the high-resolution and high-integrity development pattern exhibits the Level 1-3 details of the fingerprint,which provide effective evidence for individual identification and authentication.