A nanoparticle-supported fluorescence resonance energy transfer system formed via layer-by-layer approach as a ratiometric sensor for mercury ions in water

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• 作者：Chao Ma^a ; Fang Zeng^a ; ^{mcfzeng@scut.edu.cn} ; Guangfei Wu^a ; Shuizhu Wu^a ; ^b ; ^{shzhwu@scut.edu.cn}
• 关键词：Mercury ; Fluorescence ; Layer-by-layer ; Energy transfer ; Sensor
• 刊名：Analytica Chimica Acta
• 出版年：2012
• 期刊代码：2_00032670
• 类别：ch
• 出版时间：13 July, 2012
• 卷：734
• 期：Complete
• 页码：69-78
• 文件大小：825 K

摘要

This article describes the design and preparation of a novel fluorescence resonance energy transfer (FRET)-based ratiometric sensor with the polymer nanoparticle as scaffold for detecting Hg²⁺ in aqueous media. In this study, a fluorescent dye fluorescein isothiocyanate (FITC, served as the donor) and a spirolactam rhodamine derivative (SRHB, served as mercury ion probe) were covalently attached onto polyethylenimine (PEI) and polyacrylic acid (PAA) respectively; and a ratiometric sensing system was then formed through the deposition of the donor- and probe-containing polyelectrolytes onto the negatively charged polymer particles via the layer-by-layer approach. The ratiometric fluorescent signal change of the system is based on the intra-particle fluorescence resonance energy transfer (FRET) process modulated by mercury ions. Under optimized structural and experimental conditions, the particle-based detection system exhibits stable response for Hg²⁺ in aqueous media. More importantly, in this newly developed particle-based detection system formed by LBL approach, varied numbers of the PAA/PEI layers which served as the spacer could be placed between the donor-containing layer and the probe-containing layer, hence the donor-acceptor distance and energy transfer efficiency could be effectively tuned (from ca. 25%to 76%), this approach has well solved the problem for many particle-based FRET systems that the donor-acceptor distance cannot be precisely controlled. Also, it is found that the ratiometric sensor is applicable in a pH range of 4.6-7.3 in water with the detection limit of 200 nM. This approach may provide a new strategy for ratiometric detection of analytes in some environmental and biological applications.