Construction Of AIE-active Probes With Their Applications Based On Multicomponent Reactions

Multicomponent reactions（MCRs）are a series of organic synthesis methods,which can link three or more reactants with high efficiency in a “one-pot” route.The MCRs could also introduce novel chemical structures and functions in the final products during the procedure of MCRs.Compared to traditional stepwise methods or post-modification,this novel MCRs systems exhibited distinct advantages to much more facilely and efficiently.In this article,we design and synthesize a series of fluorescent probes with aggregation-induced emission（AIE）characteristics via MCRs systems,and exploring the fluorescent nanoparticles（FNPs）in biological imaging applications.Thus AIE polymer probes are expected to overcome the toxicities of inorganic fluorescent nanoparticles（FNPs）and the aggregation-caused quenching（ACQ）of conventional organic fluorescent molecules.Generally speaking,the major research results are as follows:1.mercaptoacetic acid locking imine（MALI）reaction,in which aldehyde AIE dyes（CHO-An-CHO）was covalently bound to NH₂-terminated polymers（PEG-PABA）by mercaptoacetic acid（MTA）as a “lock” to form amphiphilic luminescent polymers based on conventional mercaptoacetic acid locking imine（MALI）reaction at room temperature for 12 hours.The obtained polymers have amphiphilic properties and can formPEG-PABA-An-CHO FNPs by self-assembly in water,which exhibit strong yellow fluorescence and good dispersibility.In addition,we find that the PEG-PABA-An-CHO FNPs showed satisfactory biocompatibility and bioimaging properties when cultured with HeLa cells,which make them superior bioavailability potential for biomedical applications.2.Rapid preparation of branched and degradable AIE-active FNPs based on formation of dynamic phenyl borate bond.In this work,highly branched polyester H₄0,benzene-borated AIE dyes（PhB（OH）₂）and mPEG（mPEG-B（OH）₂）to form polymers H₄0-star-mPEG-PhB（OH）₂ with a dynamic phenylboronic acid ester bond based on a simple “one pot” strategy.After 30 min,thus prepared H₄0-star-mPEG-PhB（OH）₂ was obtained.Fuethermore,thanks to the H₄0 structure and AIE characteristics,thus prepared ploymers can self-assemble to form nanoparticles with uniform particle size distribution and emit strong orange-red fluorescence.Meanwhile,cell viability results indicated that H₄0-star-mPEG-PhB（OH）₂ FNPs displayed admirable biocompatibility and promising candidates for bio-imaging.On the other hand,due to the introduction of H₄0,the resultant H₄0-star-mPEG-PhB（OH）₂ FNPs have good biologic imaging properties and the formed phenylboronic acid ester bonds are responsive.Besides,this work will open up a new ways to design novel AIE-active FNPs for cancer treatment.3.Ultrafast synthesis of AIE-Active FNPs through a “One-Pot” Microwave-Assisted Kabachnik-Fields（KF）Reaction.In the air atmosphere,mPEG-CHO-Phe-NH₂-DEP was obtained by thus “one-pot”microwave-assisted,catalyst-free,solvent-free KF reaction for 2 minutes.The obtained mPEG-CHO-Phe-NH₂-DEP exhibits amphiphilic properties and were liable to self-assemble to form mPEG-CHO-Phe-NH₂-DEP FNPs,displaying unexceptionable water dispersibility and optical performance.Biological evaluation results indicate that the mPEG-CHO-Phe-NH₂-DEP FNPs present high cell activity and are potential for biological imaging applications.Above all,due to this method was fast,simple,atomic economy,more other multifunctional AIE-active FNPs can also be fabricated through the strategy described in this work.Besides,it is supposed that such facile microwave-assisted KF reaction will be a valid route for developing various AIE-active FNPs for different biomedical applications,which openes a new spring.