We propose a highly sensitive immunosensor based on the Localized Surface Plasmon Resonance (LSPR) for 17β-estradiol (E2) quantification in water. E2 molecules are recognized by polyclonal antibodies immobilized onto gold nanoparticles (AuNPs) and act as linkers that cause nanoparticles aggregation. This leads to the change in the optical properties of the solution visible even by naked eyes. The aggregates were characterized by Dynamic Light Scattering (DLS) and Scanning Transmission Electron Microscopy (STEM) and provided an accurate assessment of the inter-particle distance. The finite-difference time-domain (FDTD) method applied to a Mie problem like workspace allowed us to describe the optical behaviour of the AuNP aggregates with excellent agreement between the experimental and numerical results. The limit of detection (LOD), without any preconcentration step, is 3 pg/mL (11 pM), whereas the detection range extends over five decades up to 10⁵ pg/mL. The proposed E2 immunosensor was tested in tap water, where no significant cross-reaction signal was detected by similar molecules (testosterone, progesterone, estrone and estriol). The device described here represents a significant improvement of low E2 levels determination in terms of affordability, time and measuring simplicity, making it suitable for environmental applications.

我们提出了一种基于局部表面等离振子共振（LSPR）的高灵敏度免疫传感器，用于水中的17β-雌二醇（E2）定量。E2分子被固定在金纳米颗粒（AuNPs）上的多克隆抗体识别，并充当导致纳米颗粒聚集的连接子。这导致溶液的光学性质发生变化，即使肉眼也可见。聚集体通过动态光散射（DLS）和扫描透射电子显微镜（STEM）进行表征，并提供了对粒子间距离的准确评估。应用于工作空间等Mie问题的时域有限差分（FDTD）方法使我们能够描述AuNP聚集体的光学行为，并在实验和数值结果之间取得了很好的一致性。检测限（LOD），⁵ pg / mL。拟议中的E2免疫传感器在自来水中进行了测试，其中类似分子（睾丸激素，孕酮，雌酮和雌三醇）未检测到明显的交叉反应信号。本文所述的设备在可负担性，时间和测量简便性方面代表了低E2含量测定的显着改进，使其适用于环境应用。