Abstract—

The use of gold nanoparticles (GNPs) as carriers for the decrease in the detection limit of a fluorescence polarization (FP) aptamer assay is proposed. The common FP assay is based on the use of polarized exciting light and changes in the polarization of emitted light by the fluorophore–analyte conjugate before and after its binding with a receptor of the target analyte. Aptamers’ application as receptors in such an assay is limited due to their low molecular weight and, consequently, insufficient influence on polarization of emitted light. This limitation can be overcome by the inclusion of aptamers in larger intermolecular complexes. In the present work, the advantages of GNPs as unified, stable, and simply modified carriers for aptamers are demonstrated. The FP aptamer assay is realized with the use of GNPs with average diameter of 8.7 nm and ochratoxin A (OTA) as the target analyte. Finally, the assay is tested for OTA control in spiked white wine. The reached limit of detection is 2.3 µg/kg, which is 25-fold lower as compared to native aptamer. The time of the assay is 15 min. The universality of the proposed approach makes it possible to use aptamers for FP assays of various low-molecular-weight substances.

中文翻译：

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金纳米颗粒在O曲毒素A高灵敏度荧光偏振适体测定中的应用

摘要—

提出了使用金纳米颗粒（GNP）作为载体来降低荧光偏振（FP）适体测定的检测限的方法。常见的FP测定法是基于偏振激发光的使用以及荧光团-分析物结合物在与目标分析物受体结合之前和之后发射光的偏振变化。适体在这种测定中作为受体的应用受到限制，因为它们的分子量低，因此对发射光的偏振没有足够的影响。通过在较大的分子间复合物中包含适体可以克服该限制。在当前的工作中，展示了GNP作为适体的统一，稳定和简单修饰的载体的优势。FP适体测定是通过使用平均直径为8的GNP实现的。7 nm和曲霉毒素A（OTA）作为目标分析物。最后，对加标白葡萄酒中的OTA控制进行测试。达到的检出限为2.3 µg / kg，比天然适体低25倍。测定时间为15分钟。所提出方法的通用性使得有可能将适体用于各种低分子量物质的FP测定。