Direct label-free electrochemical detection of proteins using the polarized oil/water interface.
Direct label-free electrochemical detection of proteins using the polarized oil/water interface.
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DOI：
10.1021/la100769q
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发表时间：
2010-05
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影响因子：
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通讯作者：
T. Osakai;Yukiko Yuguchi;Emi Gohara;H. Katano
中科院分区：
文献类型：
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作者：
T. Osakai;Yukiko Yuguchi;Emi Gohara;H. Katano
研究了细胞色素c、核酸酶A、溶菌酶、白蛋白、肌红蛋白和α -乳蛋白等多种球形蛋白在极化的1,2-二氯乙烷/水（DCE/W）界面上，在四种不同阴离子表面活性剂(即二硝基萘磺酸盐（DNNS）、二（2-乙基己基）琥珀酸磺基（AOT）、二（2,2,3,3,3,4,4,5,5,6,6,7,7 -十二氟庚基）琥珀酸磺基（BDFHS）和二（2-乙基己基）磷酸（BEHP）存在下的伏安行为。当W相为酸性（pH =约3.4）时，加入到DCE中的表面活性剂（BEHP除外）促进了上述蛋白质在DCE/W界面上的吸附，并由于蛋白质的吸附/解吸而产生了发育良好的伏安波。这种伏安波，我们在这里称之为“蛋白质波”，有望用于蛋白质的直接无标记电化学检测。在过量表面活性剂存在的情况下，蛋白质吸附到界面的电流与蛋白质浓度呈线性关系。在循环伏安法中，蛋白质波出现的脚电位根据蛋白质和表面活性剂的性质而有不同的值。用不同表面活性剂测定不同蛋白质的足电位的多变量分析表明，蛋白质的选择性应取决于蛋白质分子的带电、极性和非极性表面积。在这些伏安研究的基础上，原则上表明，使用两步油/水型流动电池系统可以进行在线电化学分离/测定蛋白质。
Voltammetric behaviors of various globular proteins, including cytochrome c, ribonuclease A, lysozyme, albumin, myoglobin, and alpha-lactalbumin, were studied at the polarized 1,2-dichloroethane/water (DCE/W) interface in the presence of four different anionic surfactants, that is, dinonylnaphthalenesulfonate (DNNS), bis(2-ethylhexyl)sulfosuccinate (Aerosol-OT; AOT), bis(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl)sulfosuccinate (BDFHS), and bis(2-ethylhexyl)phosphate (BEHP). When the W phase was acidic (pH = approximately 3.4), the surfactants (except for BEHP) added to DCE facilitated the adsorption of the above proteins to the DCE/W interface and gave a well-developed voltammetric wave due to the adsorption/desorption of the proteins. This voltammetric wave, which we here call "protein wave", is promising for direct label-free electrochemical detection of proteins. The current for the adsorption of a protein to the interface showed a linear dependence on the protein concentration in the presence of excess surfactant. The foot potential at which the protein wave appeared in cyclic voltammetry showed different values depending on the natures of the protein and surfactant. Multivariate analysis for the foot potentials determined for different proteins with different surfactants revealed that the protein selectivity should depend on the charged, polar, and nonpolar surface areas of a protein molecule. On the basis of these voltammetric studies, it was shown in principle that online electrochemical separation/determination of proteins could be performed using a two-step oil/water-type flow-cell system.