基于金纳米粒子的动态光散射法检测溶液中的汞离子

Gold Nanoparticle-based Dynamic Light Scattering Assay for Detection of Mercury Ion

发展了种基于汞离子(Hg2+)适配体(Aptamer)免标记金纳米粒子的动态光散射(DLS)法,用于灵敏、选择性的检测溶液中的Hg2+。Aptamer 5'-TTTCTTCTTTCTTCCCCCCTTGTTTGTTGTTT-3'与Hg2+的特异性结合使金纳米粒子失去保护,在含有100 mmol/L NaCl的缓冲溶液中发生聚集,金纳米粒子的平均水合粒径变大。在pH=7.43,110 nmol/L Aptamer,100 mmol/L NaCl,Hg2+与Probe DNA孵育时间为30 min的实验条件下,金纳米粒子水合粒径的变化值("D)与Hg2+的浓度成正比。检出Hg2+的线性范围为0.1 nmol/L^5μmol/L,检出限达0.1 nmol/L。湖水及矿泉水两种水样加标实验表明本方法能够用于实际水样中Hg2+的检测。

A gold nanoparticle （GNP）-based dynamic light scattering （DLS） assay has been developed for detecting mercury ion （ Hg2＋ ） in aqueous solution. The GNPs are able to maintain monodisperse state in relative high ionic strength （ 0. 1 mol/L NaC1 ） aqueous solution because Hg2＋ aptamer 5＇-TITCTI＇CTITCTI＇CCCCCCTI＇GTITGTI＇GTIT-3＇（Probe DNA） can adsorb on the GNP surface by electrostatic interaction. In the presence of Hg2＋, the Probe DNA molecules easily desorb from GNP surface because of T-Hg2＋-T formation. The unprotected GNPs form aggregates in 100 mmol/L NaC1 solution, resulting in increased significantly the average hydrodynamic diameter of GNPs. Under the conditions of pH 7.43, 110 nmol/L aptamer, 100 mmol/L NaC1 and 30 minutes incubation time of Hg2＋ with aptamer, the difference of average hydrodynamic diameter （AD） of GNPs was increased linearly with logarithm of Hg2＋ concentration over the range from 0.1 nmol/L to 5 μmol/L, with a detection limit of 0.1 nmol/L. Moreover, satisfactory results were obtained when the proposed method was applied to detect Hg2＋ in real samples.