基于纳米金Core-satellites等离子体耦合增强效应的汞离子光纤传感器的研究

以DNA杂交双链为联接, 构建纳米金颗粒Core-satellites结构并激发等离子体耦合增强效应,利用Hg2+可与DNA中胸腺嘧啶T形成T-Hg2+-T特异性结构,研制了用于检测水中Hg2+的局域等离子体共振(LSPR)光纤传感器.待测溶液中的Hg2+能够引起富含T的DNA单链折叠,抑制DNA杂交反应,降低等离子体耦合强度,改变LSPR谐振波长.通过检测谐振波长红移变化,实现对Hg2+浓度的定量检测.本方法检测Hg2+的线性范围为5~150 nmol/L, 检出限为3.4 nmol/L (3σ). Zn2+、Mg2+、Pb2+等重金属离子对Hg2+检测无明显干扰作用.实际水样中Hg2+加样回收率为94.2%~105.4%,相对标准偏差<4.8%.

A Fiber-Optic Sensor Based on Plasmon Coupling Effects inGold Nanoparticles Core-Satellites Nanostructures for Detection of Mercury Ions

Based on the plasmon coupling effect in gold nanoparticles core-satellite nanostructures linked by thymine(T)-rich DNA hybridization and the specific Hg2+-mediated T-Hg2+-T base pair, a novel localized surface plasmon resonance (LSPR) optical fiber sensor was proposed and developed for Hg2+ detection in water.The Hg2+-induced conformational change in T-rich DNA sequence inhibited the DNA hybridization reaction, weakened the plasmon coupling effect and leaded to the change of LSPR resonance wavelength.The concentration of Hg2+ was quantitatively determined by the resonance wavelength redshift.The linear range of Hg2+ detection was about 5-150 nmol/L with LOD about 3.4 nmol/L.The specificity of the sensor was proved great by evaluating the response to other heavy metal ions such as Zn2+, Mg2+, Pb2+ and so on.This sensor was applied in environmental water detection by standard addition method,with the RSD less than 4.8% and recoveries of 94.2%-105.4%.