Atrazine is a widely used herbicide in the United States; however, the Environmental Protection Agency (EPA) has issued warnings about atrazine because of its reported potential harmful effects on animals and humans. Therefore, developing efficient ways to detect this herbicide's residue are critically important. The competitive ELISA is a useful method for detecting chemicals for which antibodies exist due to its high sensitivity, specificity, and efficiency. However, the assay typically requires a separate application of a secondary antibody linked to an enzyme that catalyzes conversion of a non-colored organic to a detectable colored product. In this study, we used the recently developed peroxidase-like mesoporous core-shell palladium@platinum (Pd@Pt) nanoparticle which can easily be bound directly to primary antibody, thereby eliminating the need for a secondary antibody conjugate. We report a first instance in which this technique is applied for use in a competitive assay for small molecules, in this case the herbicide atrazine. Due to their high-surface area and mesoporous structure, Pd@Pt nanoparticles enable fast mass transfer for reaction with excellent catalytic activity. This leads to high sensitivity in our immunoassay with a limit of detection of 0.5 ng mL-1 defined by selecting an IC10 concentration, i.e., the analyte concentration at which 10% of the available Pd@Pt nanoparticle-labeled antibody is inhibited from binding to a plate coated with a bovine serum albumin-atrazine conjugate. We applied our method to well-water and pond water samples spiked with atrazine. Our tests at 5, 10, and 20 ng mL-1 yielded recoveries of 99 - 115%, offering strong supporting evidence that atrazine and other low molecular weight herbicides and pesticides can be detected using this immunoassay approach. Detection with this method is expected to lead to its use in a wide spectrum of applications in agriculture, medical, and biotechnology arenas.

中文翻译：

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用于检测阿特拉津的介孔 Pd@Pt 纳米颗粒连接免疫吸附测定

阿特拉津是美国广泛使用的除草剂；然而，环境保护署 (EPA) 已经发布了关于阿特拉津的警告，因为据报道它对动物和人类有潜在的有害影响。因此，开发检测这种除草剂残留的有效方法至关重要。由于其高灵敏度、特异性和效率，竞争性 ELISA 是检测存在抗体的化学品的有用方法。然而，该测定通常需要单独应用与酶连接的二抗，该酶催化无色有机物向可检测的有色产物的转化。在这项研究中，我们使用了最近开发的类似过氧化物酶的介孔核壳钯@铂（Pd@Pt）纳米颗粒，它可以很容易地直接与一抗结合，从而消除了对二抗偶联物的需要。我们报告了该技术用于小分子的竞争性测定的第一个实例，在这种情况下是除草剂莠去津。由于其高表面积和介孔结构，Pd@Pt 纳米粒子能够以优异的催化活性实现快速传质反应。这导致我们的免疫测定具有高灵敏度，通过选择 IC10 浓度定义的检测限为 0.5 ng mL-1，即抑制 10% 可用 Pd@Pt 纳米颗粒标记抗体与涂有牛血清白蛋白-莠去津缀合物的平板。我们将我们的方法应用于添加阿特拉津的井水和池塘水样。我们在 5、10 和 20 ng mL-1 下的测试产生了 99 - 115% 的回收率，提供强有力的支持证据表明可以使用这种免疫测定方法检测莠去津和其他低分子量除草剂和杀虫剂。预计使用这种方法进行检测将导致其在农业、医疗和生物技术领域的广泛应用中使用。