Selective staining of CdS on ZnO biolabel for ultrasensitive sandwich-type amperometric immunoassay of human heart-type fatty-acid-binding protein and immunoglobulin G
Selective staining of CdS on ZnO biolabel for ultrasensitive sandwich-type amperometric immunoassay of human heart-type fatty-acid-binding protein and immunoglobulin G
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ZnO 生物标记上 CdS 的选择性染色用于人心脏型脂肪酸结合蛋白和免疫球蛋白 G 的超灵敏夹心型电流免疫分析
DOI：
10.1016/j.bios.2016.12.051
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发表时间：
2017
影响因子：
12.6
通讯作者：
Xie Qingji
中科院分区：
文献类型：
--
作者：
Qin Xiaoli;Xu Aigui;Liu Ling;Sui Yuyun;Li Yunlong;Tan Yueming;Chen Chao;Xie Qingji
我们报道了一种超灵敏的蛋白质的金属标记安培免疫分析方法，它基于纳米硫化镉(CDS)在氧化锌纳米晶上的选择性染色和免疫电极上的原位微升液滴阳极溶出伏安法(ASV)检测。将抗体1、牛血清白蛋白、抗原和氧化锌多壁碳纳米管标记的抗体2先后固定在β-环糊精-石墨烯片纳米复合材料修饰的玻碳电极上，形成夹心型免疫电极。通过Cd(NO3)2和硫代乙酰胺的化学反应(氧化锌标记/硫代乙酰胺染色)，在催化的氧化锌表面选择性地生长了硫化镉，这是因为氧化锌表面存在一个活化的氢氧化镉络合物，可以分解硫代乙酰胺。预先在空气中进行阴极“电位控制”，然后在免疫电极上注入7μL 0.1M的HNO3溶液，使染色的镉溶解，原子镉同时阴极预富集到电极表面，因此后续的原位ASV检测可用于提高灵敏度的免疫分析。在优化的条件下，该方法灵敏度高、选择性好、试剂用量小，可用于人免疫球蛋白G和人心肌型脂肪酸结合蛋白的分析，检出限(LOD，S/N=3)分别为0.4Fg·mLIg-1和0.3Fg·−-−-1(相当于6μL样品中73个FABP分子)。
We report on an ultrasensitive metal-labeled amperometric immunoassay of proteins, which is based on the selective staining of nanocrystalline cadmium sulfide (CdS) on ZnO nanocrystals and in-situ microliter-droplet anodic stripping voltammetry (ASV) detection on the immunoelectrode. Briefly, antibody 1 (Ab1), bovine serum albumin (BSA), antigen and ZnO-multiwalled carbon nanotubes (MWCNTs) labeled antibody 2 (Ab2-ZnO-MWCNTs) were successively anchored on aβ-cyclodextrin-graphene sheets (CD-GS) nanocomposite modified glassy carbon electrode (GCE), forming a sandwich-type immunoelectrode (Ab2-ZnO-MWCNTs/antigen/BSA/Ab1/CD-GS/GCE). CdS was selectively grown on the catalytic ZnO surfaces through chemical reaction of Cd(NO3)2and thioacetamide (ZnO-label/CdS-staining), due to the presence of an activated cadmium hydroxide complex on ZnO surfaces that can decompose thioacetamide. A beforehand cathodic "potential control" in air and then injection of 7 μL of 0.1 M aqueous HNO3on the immunoelectrode allow dissolution of the stained CdS and simultaneous cathodic preconcentration of atomic Cd onto the electrode surface, thus the following in-situ ASV detection can be used for immunoassay with enhanced sensitivity. Under optimized conditions, human immunoglobulin G (IgG) and human heart-type fatty-acid-binding protein (FABP) are analyzed by this method with ultrahigh sensitivity, excellent selectivity and small reagent-consumption, and the limits of detection (LODs,S/N=3) are 0.4 fg mL−1for IgG and 0.3 fg mL−1for FABP (equivalent to 73 FABP molecules in the 6 μL sample employed).