Environmentally Safe Mercury(II) Ions Aided Zero-Background and Ultrasensitive SERS Detection of Dipicolinic Acid,Analytical Chemistry

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Environmentally Safe Mercury(II) Ions Aided Zero-Background and Ultrasensitive SERS Detection of Dipicolinic Acid
Analytical Chemistry ( IF 6.7 ) Pub Date : 2017-09-20 00:00:00 , DOI: 10.1021/acs.analchem.7b02172
Xiang-Ru Bai ₁ , Yi Zeng ₁ , Xiao-Dong Zhou ₁ , Xiao-Hua Wang ₁ , Ai-Guo Shen ₁ , Ji-Ming Hu ₁

Affiliation

Field, reliable, and ultrasensitive detection of dipicolinic acid (DPA), a general biomarker of bacterial spores and especially Bacillus anthracis, is highly desirable but still challenging in current biometric security emergency response system. Herein we report an environmentally safe mercury(II) ions-mediated and competitive coordination interaction based approach for rationally designed surface-enhanced Raman scattering (SERS)-active gold nanoparticles (AuNPs), enabling rapid, ultrasensitive and zero-background detection of DPA without the pretreatment of samples. By means of competitiveness, these papain-capped gold nanoparticles (P-AuNPs) are induced to undergo controllable aggregation upon the addition of Hg²⁺ ions and DPA with a concentration range (1 nM∼8 μM), which correspondingly cause quantitative changes of SERS intensity of cresyl violet acetate (CVa) conjugated AuNPs. The decreased Raman intensity obtained by subtracting two cases of additives that contain only Hg²⁺ and the mixture of Hg²⁺ and DPA is proportional to the concentration of DPA over a range of 1 nM∼8 μM (R² = 0.9824), with by far the lowest limit of detection (LOD) of 67.25 pM (0.01 ppb, S/N = 3:1). Of particular significance, mercury(II) ions actually play two roles in the process of measurements: a mediator for two designed competitive ligands (DPA and papain), and also a scavenger for the possibly blended ligands due to the different interaction time between DPA and the interferent with Hg²⁺ ions, which guarantees the interference-free detection of DPA even under real conditions.

中文翻译：

对环境安全的汞（II）离子辅助的双吡啶甲酸零背景和超灵敏SERS检测

现场，可靠和超灵敏的检测二吡啶甲酸（DPA）是细菌孢子，尤其是炭疽芽孢杆菌的一般生物标志物，是非常需要的，但在当前的生物安全紧急响应系统中仍然具有挑战性。在此，我们报告了一种基于环境安全的汞（II）离子介导和竞争性配位相互作用的方法，用于合理设计的表面增强拉曼散射（SERS）-活性金纳米颗粒（AuNPs），能够快速，超灵敏和零背景检测DPA而无需样品的预处理。通过竞争，在添加Hg ^2+后，这些木瓜蛋白酶封闭的金纳米颗粒（P-AuNPs）被诱导进行可控的聚集。浓度范围为（1 nM〜8μM）的离子和DPA，会相应地导致乙酸甲酚紫酯（CVa）共轭AuNPs的SERS强度发生定量变化。通过减去两种仅包含Hg ²⁺以及Hg ²⁺和DPA混合物的添加剂得到的拉曼强度降低与DPA浓度在1 nM〜8μM范围内成正比（R ² = 0.9824），到目前为止的最低检测限（LOD）为67.25 pM（0.01 ppb，S / N= 3：1）。尤其重要的是，汞（II）离子实际上在测量过程中起着两个作用：两个设计的竞争性配体（DPA和木瓜蛋白酶）的介体，以及由于DPA和木瓜之间的相互作用时间不同，还可能掺混了配体的清除剂。 Hg ²⁺离子的干扰物，即使在真实条件下也能确保DPA的无干扰检测。

更新日期：2017-09-20

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