title: Novel highly selective and reversible chemosensors based on dual-ratiometric fluorescent electrospun nanofibers with pH- and Fe(3+)-modulated multicolor fluorescence emission.
abstract: Novel dual-ratiometric fluorescent electrospun (ES) nanofibers featuring high sensitivity for pH and ferric ion (Fe(3+)) were prepared using binary blends of poly(2-hydroxyethyl methacrylate-co-N-methylolacrylamide-co-nitrobenzoxadiazolyl derivative) (poly(HEMA-co-NMA-co-NBD)) and a spirolactam rhodamine derivative (SRhBOH) by employing a single-capillary spinneret. The HEMA, NMA, and NBD moieties were designed to exhibit hydrophilic properties, chemical cross-linking, and fluorescence (fluorescence resonance energy transfer (FRET) donor), respectively. The fluorescence emission of SRhBOH was highly selective for pH and Fe(3+); when SRhBOH detected acidic media and Fe(3+), the spirocyclic form of SRhBOH, which is nonfluorescent, was transformed into the opened cyclic form and exhibited strong fluorescence emission. The emission colors of ES nanofibers in acidic or Fe(3+) aqueous solutions changed from green to red because of FRET from NBD (donor) to SRhBOH (acceptor). The off/on switching of the FRET process was modulated by adjusting the SRhBOH blending ratio, pH, and Fe(3+) concentration. Poly(HEMA-co-NMA-co-NBD) ES fibers blended with 20% SRhBOH showed high sensitivity in sensing Fe(3+) and pH because of the substantial 57 nm red shift in emission as well as substantial reversible dual photoluminescence. The prepared FRET-based dual-ratiometric fluorescent ES nanofibrous membranes can be used as "naked eye" sensors and have potential for application in multifunctional environment sensing devices.
authors.affiliation: Institute of Organic and Polymeric Materials, National Taipei University of Technology , 10608 Taipei, Taiwan.
authors.forename: Bo-Yu
authors.initials: BY
authors.lastname: Chen
authors.forename: Chi-Ching
authors.initials: CC
authors.lastname: Kuo
authors.forename: Yun-Shao
authors.initials: YS
authors.lastname: Huang
authors.forename: Shih-Tung
authors.initials: ST
authors.lastname: Lu
authors.forename: Fang-Cheng
authors.initials: FC
authors.lastname: Liang
authors.forename: Dai-Hua
authors.initials: DH
authors.lastname: Jiang
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057139:Nanofibers / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry*
chemical_list: D000178:Acrylamides; D005290:Ferric Compounds; D005456:Fluorescent Dyes; D012235:Rhodamines; C066443:N-methylolacrylamide
keywords: electrospun (ES) nanofibers; ferric ion; luminescence; pH; sensor