title: Far Red/Near-Infrared AIE Dots for Image-Guided Photodynamic Cancer Cell Ablation.
abstract: We report a facile encapsulation approach to realize bright far red/near-infrared (FR/NIR) fluorescence and efficient singlet oxygen ((1)O2) production of organic fluorogens with aggregation-induced emission (AIEgen) and intramolecular charge transfer (ICT) characteristics for image-guided photodynamic cancer cell ablation. The synthesized AIEgen BTPEAQ possesses donor-acceptor-donor structure, which shows bright fluorescence in solid state. Due to the strong ICT effect, BTPEAQ exhibits poor emission with almost no (1)O2 generation in aqueous solution. Encapsulation of BTPEAQ by DSPE-PEG block copolymer yields polymer-shelled dots, which show enhanced brightness with a fluorescence quantum yield of 3.9% and a (1)O2 quantum yield of 38%. Upon encapsulation by silica, the formed SiO2-shelled dots show much improved fluorescence quantum yield of 12.1% but with no obvious (1)O2 generation. This study clearly demonstrates the importance of encapsulation approach for organic fluorophores, which affects not only the brightness but also the (1)O2 production. After conjugating the polymer-shelled AIE dots with cRGD peptide, the obtained BTPEAQ-cRGD dots show excellent photoablation toward MDA-MB-231 cells with integrin overexpression while keeping control cells intact.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585.
authors.forename: Guangxue
authors.initials: G
authors.lastname: Feng
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585.|Department of Materials Science and Engineering, National University of Singapore , 7 Engineering Drive 1, Singapore 117574.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Wu
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585.
authors.forename: Shidang
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585.|Institute of Materials Research and Engineering (IMRE) , 2 Fusionopolis Way, Innovis, Singapore 136834.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
mesh_terms: D005453:Fluorescence; D005456:Fluorescent Dyes; D006801:Humans; D053758:Nanoparticles; D009369:Neoplasms; D011108:Polymers; D012822:Silicon Dioxide
chemical_list: D005456:Fluorescent Dyes; D011108:Polymers; D012822:Silicon Dioxide
keywords: aggregation-induced emission; bioimaging; nanoparticles; photodynamic therapy; theranostics