State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
School of Environment, Hangzhou Institution for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China.
Anal Methods. 2024 Sep 26;16(37):6356-6363. doi: 10.1039/d4ay01283f.
Detecting β-estradiol (E2) in environmental monitoring is a complex task due to its status as a significant environmental contaminant. The detection methods require precision, sensitivity, and the ability to be conducted on-site without expensive instrumentation. Herein, we developed a novel approach using E2 aptamer assembled spherical nucleic acids (SNAs), which combines the sensitivity of fluorescence and the simplicity of colorimetry. Initially, a fluorescein (FAM)-labeled DNA aptamer is attached to the surface of gold nanoparticles (AuNPs) through hybridization with thiol-labeled DNA, resulting in fluorescence quenching. However, when E2 is present, the aptamer specifically binds to it, displacing from the thiol-DNA and releasing from the AuNP's surface. This leads to the recovery of fluorescence, allowing for quantitative detection of E2 by measuring the increase in fluorescence signal. Additionally, E2 detection can also be achieved visually using ultraviolet light. For colorimetric analysis, we introduce another set of AuNPs modified with thiol-DNA complementary to the DNA remaining on the surface of the previous AuNPs. When E2 triggers the release of the aptamer, the DNA on both AuNPs hybridized to each other, causing the aggregation of AuNPs and resulting in a distinct color change from red to purple. The detection limits for fluorescence and colorimetric analyses are 1 nM and 5 nM, respectively. We successfully applied this biosensing strategy to determine E2 concentrations in tap water and serum samples. Furthermore, our assay exhibits high selectivity towards E2 over other estrogens. Overall, this innovative approach provides an effective and versatile method for convenient on-site monitoring of E2.
检测环境监测中的β-雌二醇（E2）是一项复杂的任务，因为它是一种重要的环境污染物。检测方法需要精确、灵敏，并能够在没有昂贵仪器的情况下进行现场检测。在此，我们开发了一种使用 E2 适体组装的球形核酸（SNA）的新方法，该方法结合了荧光的灵敏度和比色法的简单性。首先，通过与巯基标记的 DNA 杂交，将荧光标记的 DNA 适体附着在金纳米粒子（AuNPs）的表面上，导致荧光猝灭。然而，当存在 E2 时，适体特异性地与其结合，从巯基-DNA 上置换出来并从 AuNP 的表面释放。这导致荧光恢复，通过测量荧光信号的增加来定量检测 E2。此外，还可以使用紫外线光进行 E2 的目视检测。对于比色分析，我们引入了另一组修饰有与 AuNPs 表面上剩余 DNA 互补的巯基-DNA 的 AuNPs。当 E2 触发适体释放时，两个 AuNPs 上的 DNA 相互杂交，导致 AuNP 聚集，并导致从红色到紫色的明显颜色变化。荧光和比色分析的检测限分别为 1 nM 和 5 nM。我们成功地将这种生物传感策略应用于测定自来水中和血清样品中的 E2 浓度。此外，我们的测定法对 E2 表现出高于其他雌激素的高选择性。总的来说，这种创新方法为方便现场监测 E2 提供了一种有效且多功能的方法。
