Yin Xue-Bo, Qi Bin, Sun Xuping, Yang Xiurong, Wang Erkang
State Key Laboratory of Electroanalytical Chemistry, Changchun Insititute of Applied Chemistry, Chinese Academy of Science, Changchun, 130022, China.
Anal Chem. 2005 Jun 1;77(11):3525-30. doi: 10.1021/ac0503198.
4-(Dimethylamino)butyric acid (DMBA) labeling combined with gold nanoparticle amplification for electrochemiluminescence (ECL) determination of a biological substance (bovine serum albumin (BSA) and immunoglobulin G (IgG) as models) was presented. After DMBA, an analogue of tripropylamine, was tagged on the (anti)analytes, an ECL signal related to the content of the analytes was generated when the analyte tagged with DMBA was in contact with tris(2,2'-bipyridine)ruthenium (Ru(bpy)(3)2+) solution and a potential was applied. To improve the adsorption capacity, a gold nanoparticle layer was first combined into the surface of the 2-mm-diameter gold electrode. For the determination of BSA, avidin was covalently conjugated to a self-assembled monolayer of 3-mercaptopropanoic acid on the gold nanoparticle layer. Biotinylated BSA-DMBA was then immobilized on the gold nanoparticle layer of the gold electrode via the avidin-biotin reaction. IgG was tested via a typical sandwich-type immobilization method. ECL signals were generated from the electrodes immobilized with BSA or IgG by immersing them in a 1 mmol L-1 Ru(bpy)(3)2+ solution and scanning from 0.5 to 1.3 V versus Ag/AgCl. With gold nanoparticle amplification, the ECL peak intensity was proportional to the concentration over the range 1-80 and 5-100 microg/mL for BSA and IgG consuming 50 microL of sample, respectively. A 10- and 6-fold sensitivity enhancement was obtained for BSA and IgG over their direct immobilization on an electrode using DMBA labeling. The relative standard deviations of five replicate determinations of 10 microg/mL BSA and 20 microg/mL IgG were 8.4 and 10.2%, respectively. High biocompatibility and low cost were the main advantages of the present DMBA labeling technique over the traditional Ru(bpy)(3)2+ labeling.
本文提出了一种结合4-(二甲基氨基)丁酸(DMBA)标记和金纳米粒子放大的电化学发光(ECL)方法，用于测定生物物质（以牛血清白蛋白(BSA)和免疫球蛋白G (IgG)为模型）。在将三丙胺类似物DMBA标记在（抗）分析物上后，当标记有DMBA的分析物与三(2,2'-联吡啶)钌(Ru(bpy)(3)2+)溶液接触并施加电位时，会产生与分析物含量相关的ECL信号。为提高吸附能力，首先在直径2 mm的金电极表面结合一层金纳米粒子。测定BSA时，将抗生物素蛋白共价偶联到金纳米粒子层上的3-巯基丙酸自组装单分子层上。然后通过抗生物素蛋白-生物素反应将生物素化的BSA-DMBA固定在金电极的金纳米粒子层上。IgG通过典型的夹心型固定方法进行检测。将固定有BSA或IgG的电极浸入1 mmol L-1 Ru(bpy)(3)2+溶液中，相对于Ag/AgCl从0.5 V扫描至1.3 V，从而产生ECL信号。通过金纳米粒子放大，对于消耗50 μL样品的BSA和IgG，ECL峰强度分别在1-80和5-100 μg/mL范围内与浓度成正比。与使用DMBA标记直接固定在电极上相比，BSA和IgG的灵敏度分别提高了10倍和6倍。10 μg/mL BSA和20 μg/mL IgG的五次重复测定的相对标准偏差分别为8.4%和10.2%。与传统的Ru(bpy)(3)2+标记相比，本DMBA标记技术的主要优点是具有高生物相容性和低成本。
