Ultrasensitive detection of Cu2+ with the naked eye and application in immunoassays
Ultrasensitive detection of Cu2+ with the naked eye and application in immunoassays
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Cu2+肉眼超灵敏检测及其在免疫分析中的应用
DOI：
10.1038/am.2012.18
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发表时间：
2012-03-01
影响因子：
9.7
通讯作者：
Yang, Huang-Hao
中科院分区：
文献类型：
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作者：
Lu, Chun-Hua;Wang, Yi-Wei;Yang, Huang-Hao
本研究开发了一种利用纳米金（AuNPs）快速、灵敏、选择性地检测Cu2+的新方法，并将其用于免疫分析。在l -半胱氨酸存在的情况下，l -半胱氨酸可以通过Au-S键结合到柠檬酸盐稳定的AuNPs表面。因此，通过半胱氨酸结合的AuNPs之间的静电相互作用，AuNPs聚集发生。相反，在Cu2+的存在下，Cu2+可以催化半胱氨酸的O-2氧化，导致快速形成二硫半胱氨酸。随着Cu2+浓度的增加，l -半胱氨酸诱导的AuNPs聚集通过减少游离半胱氨酸巯基数量而减少，溶液颜色由紫色变为红色。因此，可以用肉眼或紫外-可见光谱法检测Cu2+的浓度，Cu2+的检出限分别为20 nM和10 nM。该灵敏度比传统的基于aunps的比色Cu2+检测方法高出约三个数量级。由于该方法的高灵敏度，我们进一步将其与标记抗体一起用于比色免疫测定。肿瘤生物标志物甲胎蛋白的检出限为2 ng ml(-1)，与酶联免疫吸附法的检出限相当。核电材料，2012,4,e10；doi: 10.1038 / am.2012.18;2012年3月16日在线发布
In this study, a novel method for the fast, sensitive and selective detection of Cu2+ using gold nanoparticles (AuNPs) was developed and used in immunoassays. In the presence of L-cysteine, L-cysteine can bind to the surface of citrate-stabilized AuNPs through Au-S bonds. As a result, aggregation of AuNPs occurs through electrostatic interactions between the cysteine-bound AuNPs. In contrast, in the presence of Cu2+, Cu2+ can catalyze O-2 oxidation of cysteine, leading to the quick formation of disulfide cystine. An increase in the concentration of Cu2+ decreased L-cysteine-induced AuNPs aggregation by decreasing the number of free cysteine thiol groups, and the solution color changed from purple to red. Therefore, the concentration of Cu2+ can be detected with the naked eye or with ultraviolet-visible spectroscopy, and the detection limits of Cu2+ were 20 nM and 10 nM, respectively. This sensitivity was approximately three orders of magnitude higher than that of traditional AuNPs-based colorimetric Cu2+ detection methods. Because of the high sensitivity of the proposed method, we further used it with a labeled antibody in colorimetric immunoassays. The detection limit of the cancer biomarker alpha-fetoprotein was 2 ng ml(-1), which is comparable to the detection limit of the enzyme-linked immunosorbent assay method. NPG Asia Materials (2012) 4, e10; doi: 10.1038/am.2012.18; published online 16 March 2012