Institute of Intelligent Machines, Chinese Academy of Sciences, PO Box 1130, Hefei, Anhui 230031, China.
Chemistry. 2010 Mar 22;16(12):3720-7. doi: 10.1002/chem.200902721.
This paper reports a reversible dual fluorescence switch for the detection of a proton target and 2,4,6-trinitrotoluene (TNT) with opposite-response results, based on fluorophore derivatization of silica nanoparticles. Fluorescent silica nanoparticles were synthesized through modification of the surface with a nitrobenzoxadiazole (NBD) fluorophore and an organic amine to form a hybrid monolayer of fluorophores and amino ligands; the resultant nanoparticles showed different fluorescence responses to the proton target and TNT. Protonation of the amino ligands leads to fluorescence enhancement due to inhibition of photoinduced electron transfer (PET) between the amine and fluorophore. By contrast, addition of TNT results in fluorescence quenching because a fluorescence resonance energy transfer (FRET) happens between the NBD fluorophore and the formed TNT-amine complex. The fluorescence signal is reversible through washing with the proper solvents and the nanoparticles can be reused after centrifugal separation. Furthermore, these nanoparticles were assembled into chips on an etched silicon wafer for the detection of TNT and the proton target. The assembled chip can be used as a convenient indicator of herbicide (2,4-dichlorophenoxyacetic acid) and TNT residues with the use of only 10 microL of sample. The simple NBD-grafted silica nanoparticles reported here show a reversible signal and good assembly flexibility; thus, they can be applied in multianalyte detection.
本文报道了一种基于荧光染料衍生化的二氧化硅纳米粒子的可逆双通道荧光开关，用于检测质子靶和 2,4,6-三硝基甲苯（TNT），具有相反的响应结果。通过用硝基苯并恶二唑（NBD）荧光染料和有机胺修饰表面，合成了荧光二氧化硅纳米粒子，形成了荧光染料和氨基配体的混合单层；所得纳米粒子对质子靶和 TNT 表现出不同的荧光响应。由于胺和荧光团之间的光诱导电子转移（PET）受到抑制，氨基配体的质子化导致荧光增强。相比之下，加入 TNT 会导致荧光猝灭，因为 NBD 荧光团和形成的 TNT-胺复合物之间发生荧光共振能量转移（FRET）。通过用适当的溶剂洗涤，荧光信号是可逆的，并且纳米粒子可以在离心分离后重复使用。此外，这些纳米粒子被组装到蚀刻硅晶片上用于检测 TNT 和质子靶。组装后的芯片可以用作除草剂（2,4-二氯苯氧基乙酸）和 TNT 残留的便捷指示剂，只需 10 μL 样品即可使用。本文报道的简单的 NBD 接枝二氧化硅纳米粒子表现出可逆信号和良好的组装灵活性；因此，它们可应用于多分析物检测。
