One-pot fabrication of polymer nanoparticle-based chemosensors for Cu2+ detection in aqueous mediaElectronic supplementary information (ESI) available: Characterizations, schemes, absorption and fluorescence spectra, as well as photographs. Detailed description of calculation of the Förster radii (R0) and experimental energy transfer efficiency. See DOI: 10.1039/c3py21131b

• Main Authors: Zhang, Peisheng, Chen, Jian, Huang, Fuhua, Zeng, Zhiqiang, Hu, Jia, Yi, Pinggui, Zeng, Fang, Wu, Shuizhu
• Format: Article
• Language: English
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/c3py21131b

Cupric pollution is a global problem, and the development of stable and sensitive fluorescent probes for cupric ions in the water phase has long been sought. In the present study, we report on the fabrication of core-shell nanoparticle-based fluorescent chemosensors for Cu 2+ detection in aqueous media. The core-shell nanoparticle sensor was prepared by a facile one-pot miniemulsion polymerization, in which the fluorescent dye (4-methamino-9-allyl-1,8-naphthalimide, MANI) was covalently incorporated into particle core and the Cu 2+ ligand i.e. Vinylbenzylcyclam (VBC), chemically linked onto the surface. The cyclam-functionalized fluorescent polymeric nanoparticles exhibit a high affinity for Cu 2+ ions in aqueous media. Upon the addition of Cu 2+ , the fluorescent emission of the MANI dye in nanoparticles can be quenched on the basis of intraparticle fluorescence resonance energy transfer (FRET) from the dye in the hydrophobic PMMA core to the Cu 2+ -cyclam complexes on the nanoparticle surface, and the nanoparticle sensor can selectively detect the Cu 2+ in water with the detection limit of 500 nM. The observed FRET efficiencies (31.6-73.4%), as well as the distance ( r ) between MANI (donor) and Cu 2+ -cyclam complexes (acceptor), were also determined. No interference was observed from other metal ions, making it a highly sensitive and selective Cu 2+ probe. Moreover, the nanoparticle-based fluorescent sensor was applicable in a relatively wide pH range (pH 4-10) in water and it exhibited excellent long-term photostability for Cu 2+ detection (>45 days) in aqueous media; thus, this approach may provide a new strategy for ratiometric detection of analytes in environmental and biological applications. A novel fluorescent polymer nanoparticle sensor for Cu 2+ detection was prepared by one-step miniemulsion polymerization. The as-prepared nanoparticles can not only highly selectively recognize Cu 2+ in water (down to 500 nM), but also show excellent long-term fluorescence stability (>45 days) and a wide applicable pH range (4-10).