A distance-dependent metal-enhanced fluorescence sensing platform based on molecular beacon design.
A distance-dependent metal-enhanced fluorescence sensing platform based on molecular beacon design.
复制标题
DOI：
10.1016/j.bios.2013.09.013
复制
发表时间：
2014-02
影响因子：
12.6
通讯作者：
Zhenpeng Zhou;Hongduan Huang;Yang Chen;Fen Liu;C. Huang;Na Li
中科院分区：
文献类型：
--
作者：
Zhenpeng Zhou;Hongduan Huang;Yang Chen;Fen Liu;C. Huang;Na Li
基于距离依赖的荧光猝灭-增强效应，将银-硫醇化学的简单性与贵金属结构的金属增强荧光性质以及分子信标设计相结合，发展了一种新的基于金属增强荧光（MEF）的平台。对于给定尺寸的AgNP，发现荧光增强因子随着ad 6依赖性的增加而增加，这与荧光共振能量转移机制在较短距离处一致，并且随着ad− 3依赖性的减少而减少，这与荧光团和AgNP表面之间的较长距离处的等离子体增强机制一致。作为概念验证，该平台通过使用含胸腺嘧啶的分子信标来调谐银纳米颗粒（AgNP）增强的荧光，灵敏地检测汞离子来证明。通过形成胸腺嘧啶-汞-胸腺嘧啶结构以打开发夹来检测汞离子，促进荧光恢复和AgNP增强，以产生1 nM的检测限，这远低于美国环境保护署规定的饮用水中最大污染物水平目标（10 nM）。由于AgNP不仅可以作为猝灭剂降低试剂空白信号，而且还可以作为增强底物增加目标汞离子存在时开放发夹的荧光，因此猝灭-增强策略可以大大提高检测灵敏度，并且当与分子信标设计相结合时，原则上可以成为针对各种目标的通用方法。
A new metal-enhanced fluorescence (MEF) based platform was developed on the basis of distance-dependent fluorescence quenching-enhancement effect, which combined the easiness of Ag-thiol chemistry with the MEF property of noble-metal structures as well as the molecular beacon design. For the given sized AgNPs, the fluorescence enhancement factor was found to increase with ad6dependency in agreement with fluorescence resonance energy transfer mechanism at shorter distance and decrease with ad−3dependency in agreement with plasmonic enhancement mechanism at longer distance between the fluorophore and the AgNP surface. As a proof of concept, the platform was demonstrated by a sensitive detection of mercuric ions, using thymine-containing molecular beacon to tune silver nanoparticle (AgNP)-enhanced fluorescence. Mercuric ions were detected via formation of a thymine–mercuric–thymine structure to open the hairpin, facilitating fluorescence recovery and AgNP enhancement to yield a limit of detection of 1 nM, which is well below the U.S. Environmental Protection Agency regulation of the Maximum Contaminant Level Goal (10 nM) in drinking water. Since the AgNP functioned as not only a quencher to reduce the reagent blank signal but also an enhancement substrate to increase fluorescence of the open hairpin when target mercuric ions were present, the quenching-enhancement strategy can greatly improve the detection sensitivity and can in principle be a universal approach for various targets when combined with molecular beacon design.