title: Selective fluorescence turn-on and ratiometric detection of organophosphate using dual-emitting Mn-doped ZnS nanocrystal probe.
abstract: Semiconductor nanocrystals (NCs) possess unique photoluminescent properties which can be used to design fluorescence probes for chemo/biosensing applications. Several have recently emerged that offer excellent turn-on or ratiometric fluorescence chemosensory protocols by sophisticated procedures, but it has been challenging to realize all of these advantages in a single construct. Herein, we develop an intrinsic dual-emitting Mn-doped ZnS nanocrystal-based probe that achieves this goal with turn-on and ratiometric fluorescence response for the determination of organophosphate (diethylphosphorothioate, DEP). The probe relies on the modification of dopamine dithiocarbamate on the surface of NCs and the modulation of dual emission through a photoinduced electron transfer process, which makes use of red fluorescence of Mn(2+) ions doped in the NCs as specific recognition for the target analyte and blue defect emission of the NCs as stable internal reference. In presence of DEP, the red emission of the probe is thus enhanced by switching off the electron transfer pathway, while the blue emission is almost unchanged. With the addition of different amounts DEP, the two emission intensity ratios gradually vary and display color changes from dark-blue to purple to red. Thus, this method generates turn-on and ratiometric fluorescence signals for quantitative and visual detection of the analyte. Significantly, the dual-emitting probe has been used to fabricate paper-based test strips for visual detection of DEP residues, which validate the method for its rapid, on-site, and visual identification.
authors.affiliation: Institute of Intelligent Machines, Chinese Academy of Sciences , 350, Shushanhu Road, Hefei, Anhui 230031, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Zhang
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Mingtai
authors.initials: M
authors.lastname: Sun
authors.forename: Huan
authors.initials: H
authors.lastname: Yu
authors.forename: Bianhua
authors.initials: B
authors.lastname: Liu
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Zhang
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.forename: Suhua
authors.initials: S
authors.lastname: Wang
mesh_terms: D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D010755:Organophosphates / Q000032:analysis*; D013440:Sulfides / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D010755:Organophosphates; D013440:Sulfides; D017967:Zinc Compounds; D008345:Manganese; C031238:zinc sulfide