Metal-Chelating and Dansyl-Labeled Poly(N-isopropylacrylamide) Microgels as Fluorescent Cu2+ Sensors with Thermo-Enhanced Detection Sensitivity
Metal-Chelating and Dansyl-Labeled Poly(N-isopropylacrylamide) Microgels as Fluorescent Cu2+ Sensors with Thermo-Enhanced Detection Sensitivity
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DOI：
10.1021/la901377h
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发表时间：
2009-10-06
期刊：
影响因子：
3.9
通讯作者：
Liu, Shiyong
中科院分区：
文献类型：
--
作者：
Yin, Jun;Guan, Xuefeng;Liu, Shiyong
我们报告的Cu 2+传感温敏聚（N-异丙基丙烯酰胺）（PNIPAM）微凝胶标记金属螯合受体和荧光报告部分的制造。通过传感基质的热诱导塌陷，可以很容易地优化Cu 2+结合位点的相对空间分布和荧光读出功能，从而显著提高Cu 2+检测灵敏度。首先合成了一种新型的具有铜离子结合能力的含吡啶胺单体N-（2-（2-氧代-2-（2-吡啶甲氨基）乙氨基）乙基）丙烯酰胺（PyAM，3）。在非离子表面活性剂N，N '-亚甲基双丙烯酰胺（BIS）、PyAM（3）和荧光丹磺酰氨基乙基丙烯酰胺（DAEAM，5）单体的存在下，通过乳液聚合制备了近单分散的Cu 2+传感微凝胶。在20 ° C下，所合成的微凝胶在其溶胀状态下可以选择性地结合Cu 2+而不是其他金属离子（Hg 2+、Mg 2+、Zn 2+、Pb 2+、Ag+和Al 3+），导致荧光发射强度的显著淬灭。高于体积相变温度，P（NIPAM-co-PyAM-co-DAEAM）微凝胶表现出增加的荧光强度。据观察，Cu 2+检测灵敏度可以显着提高通过热诱导的微凝胶崩溃在升高的温度。在微凝胶浓度为3.0 × 10（-6）g/mL时，检测限从20 ℃时的46 nM大幅提高到45 ℃时的8 nM。初步提出了这种新型传感器的基本机制，具有可调的检测灵敏度。
We report on the fabrication of Cu2+-sensing thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) microgels labeled with metal-chelating receptor and fluorescent reporter moieties. Cu2+ detection sensitivity call be considerably enhanced via thermo-induced collapse of the sensing matrix,which can easily optimize the relative spatial distribution of Cu2+-binding sites and fluorescence readout functionalities. A novel picolinamine-containing monomer with Cu2+- binding capability, N-(2-(2-oxo-2-(pyridine 2-yl-methylamino)ethylamino)ethyl)acrylamide (PyAM, 3), was synthesized at first. Nearly monodisperse Cu2+-sensing microgels were prepared via emulsion polymerization of N-iso propylacrylamide (NIPAM) in the presence of a nonionic surfactant, N,N'-Methylene-bis(acrylamide) (BIS), PyAM (3), and fluorescent dansylaminoethyl-acrylamide (DAEAM, 5) monomers at around neutral pH and 70 degrees C. At 20 degrees C, as-synthesized microgels in their swollen state can selectively bind Cu2+ over other metal ions (Hg2+, Mg2+, Zn2+, Pb2+, Ag+, and Al3+), leading to prominent quenching of fluorescence emission intensity, Above the volume phase transition temperature, P(NIPAM-co-PyAM-co-DAEAM) microgels exhibit increased fluorescence intensity. It was observed that Cu2+ detection sensitivity can be dramatically enhanced via thermo-induced microgel collapse at elevated temperatures. At a microgel concentration of 3.0 x 10(-6) g/mL, the detection limit drastically improved from similar to 46 nM at 20 degrees C to similar to 8 nM at 45 degrees C. The underlying mechanism for this novel type of sensor with thermotunable detection sensitivity was tentatively proposed.