Responsive polymer-based multicolor fluorescent probes for temperature and Zn^(2+) ions in aqueous media  

作　　者：HU XiangLong LI Yang LIU Tao ZHANG GuoYing LIU ShiYong 

机构地区：[1]CAS Key Laboratory of Soft Matter Chemistry [2]Hefei National Laboratory for Physical Sciences at the Microscale [3]Department of Polymer Science and Engineering, University of Science and Technology of China

出　　处：《Science China Chemistry》2014年第4期615-623,共9页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(21274137,51273190,91027026,and 51033005);the Specialized Research Fund for the Doctoral Program of Higher Education(20123402130010)

摘　　要：We report on the fabrication of fluorescent and multicolor probes for Zn^2＋ ions and temperature from a mixture of three types of fluorophore-labeled responsive block copolymers in aqueous media. Quinoline-based Zn^2＋-recognizing fluorescent mono- mer ZQMA, red-emitting rhodamine B-based monomer RhBEA, and blue-emitting coumarin derivative Coum-OH, were syn- thesized first. A ZQMA-labeled well-defined double hydrophilic block copolymer （DHBC）, PEG-b-P（MEO2MA-co-ZQMA）, was synthesized via reversible addition-fragmentation chain-transfer （RAFT） polymerization of 2-（2-methoxyethoxy）ethyl methacrylate （MEOzMA） and ZQMA by utilizing a PEG-based macroRAFT agent. Following similar procedures, PEG-b-P（St-co-RhBEA） amphiphilic diblock copolymer and PEG-b-P（MEOzMA-co-Coum） DHBC were also synthesized, where P（St-co-RhBEA） was a RhBEA-labeled polystyrene （PS） block. At room temperature in aqueous solution, almost non- fluorescent PEG-b-P（MEOzMA-co-ZQMA） can effectively bind Zn2＋ ions, leading to prominent green fluorescence enhance- ment due to the coordination of ZQMA with Zn^2＋ ions. However, by mixing red-emitting PEG-b-P（St-co-RhBEA） and blue-emitting PEG-b-P（MEO2MA-co-Coum） with PEG-b-P（MEO2MA-co-ZQMA） at an appropriate ratio, three color transitions could be observed. In the absence of Zn^2＋ ions, a mixed pink fluorescent originating from Coum and RhBEA was ob- served; upon the addition of a certain amount of Zn^2＋ ions, the green fluorescence enhanced dramatically, leading to a white fluorescence readout. By further increasing the amount of Zn2＋ ions, the green fluorescence further enhanced and overwhelmed the blue and red emissions, leading to a green-dominant mixed-fluorescence emission. In addition, upon increasing the temperature, the fluorescence of Coum decreased considerably due to the fluorescence-resonance energy transfer （FRET） between Coum and ZQMA moieties. In this way, a ratiometric fluorescent thermometer can be constructed.We report on the fabrication of fluorescent and multicolor probes for Zn2+ ions and temperature from a mixture of three types of fluorophore-labeled responsive block copolymers in aqueous media. Quinoline-based Zn2+-recognizing fluorescent monomer ZQMA, red-emitting rhodamine B-based monomer RhBEA, and blue-emitting coumarin derivative Coum-OH, were synthesized first. A ZQMA-labeled well-defined double hydrophilic block copolymer(DHBC), PEG-b-P(MEO2MA-co-ZQMA), was synthesized via reversible addition-fragmentation chain-transfer(RAFT) polymerization of 2-(2-methoxyethoxy)ethyl methacrylate(MEO2MA) and ZQMA by utilizing a PEG-based macroRAFT agent. Following similar procedures, PEG-b-P(St-co-RhBEA) amphiphilic diblock copolymer and PEG-b-P(MEO2MA-co-Coum) DHBC were also synthesized, where P(St-co-RhBEA) was a RhBEA-labeled polystyrene(PS) block. At room temperature in aqueous solution, almost nonfluorescent PEG-b-P(MEO2MA-co-ZQMA) can effectively bind Zn2+ ions, leading to prominent green fluorescence enhancement due to the coordination of ZQMA with Zn2+ ions. However, by mixing red-emitting PEG-b-P(St-co-RhBEA) and blue-emitting PEG-b-P(MEO2MA-co-Coum) with PEG-b-P(MEO2MA-co-ZQMA) at an appropriate ratio, three color transitions could be observed. In the absence of Zn2+ ions, a mixed pink fluorescent originating from Coum and RhBEA was observed; upon the addition of a certain amount of Zn2+ ions, the green fluorescence enhanced dramatically, leading to a white fluorescence readout. By further increasing the amount of Zn2+ ions, the green fluorescence further enhanced and overwhelmed the blue and red emissions, leading to a green-dominant mixed-fluorescence emission. In addition, upon increasing the temperature, the fluorescence of Coum decreased considerably due to the fluorescence-resonance energy transfer(FRET) between Coum and ZQMA moieties. In this way, a ratiometric fluorescent thermometer can be constructed.

关 键 词：responsive polymers FLUORESCENCE probes Zn^2＋ THERMOMETER multicolor transition 

分 类 号：O657.3[理学—分析化学]