Intrinsically ESIPT-exhibiting and enhanced emission in polymer nanoparticles as signaling for sensing nitrite.


College of Chemistry and Food Engineering, Changsha University of Science and Technology, Changsha, 410114, PR China. Electronic address: [Email]


A straightforward approach to the fabrication of intrinsically excited-state intramolecular proton transfer (ESIPT)-fluorescent polymer nanoparticles (e-PNPs) was developed. The e-PNPs were obtained by self-assembly of the homopolymers derived from 4-aminosalicylic acid in aqueous solution. By incorporating ESIPT modules into polymer nanoparticles, the ESIPT reaction can be endowed with moderate hydrophobic micro-environment by nanoparticle scaffolds, eliciting enhanced ESIPT emission. The newly developed e-PNPs exhibit strong tautomeric fluorescence(e-FL), good photostability, low-toxicity and favourable biocompatibility in aqueous solution. Upon the addition of NO2-, the e-FL can be significantly quenched owing to the reaction of NO2- with the amide groups on e-PNPs. From this basis, the fluorescence detection of NO2- was implemented, which showed a linear relationship between 0 nM and 110 nM with a detection limit of 2.3 nM. Furthermore, e-PNPs were used as nanoprobes to monitor the NO2- levels in HeLa cells by fluorescence imaging, demonstrating the ability of discrimination from different concentrations of NO2-. The proposed method can be applied to a wide range of other ESIPT modules to integrate into polymer nanoparticles and offer highly sensitive nanosensing platform for bioanalysis and molecular imaging.


ESIPT-Exhibiting,NO(2)(-) sensing,Polymer nanoparticles,Tautomeric emission quenching,

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