Abstract：
Gold nanoparticles (AuNPs) have been widely applied to molecular sensors due to their optical properties. We previously reported a molecular detection by observing the scattered light of AuNPs at a single nanoparticle level using dark field microscopy (DFM). Recently, a molecular detection method using digital immunoassay has been reported, taking advantage of the characteristics of DFM. However, the digital immunoassays reported so far have been performed by a conventional sandwich immunoassay, which is difficult to apply to the detection of small molecules. In this study, with the aim of small molecule detection, we developed a digital immunoassay method using an anti-immunocomplex antibody that specifically recognizes immunocomplexes of small molecules with antibodies. The number of AuNPs modified with anti-immunocomplex antibody bound to immunocomplex of estradiol and anti-estradiol antibody was counted at a single nanoparticle level using DFM. We demonstrated for the first time that estradiol molecule can be detected by digital immunoassay using DFM and an anti-immunocomplex antibody with a detection sensitivity of 1 pg/mL.
摘要：
金纳米粒子(AuNPs)由于其光学性质而被广泛应用于分子传感器中。我们先前通过使用暗视野显微镜（DFM）在单个纳米颗粒水平上观察AuNP的散射光来报道分子检测。最近,已经报道了一种使用数字免疫分析的分子检测方法，利用DFM的特点。然而,迄今为止报道的数字免疫测定是通过传统的夹心免疫测定进行的，难以应用于小分子的检测。在这项研究中,为了小分子检测，我们开发了一种使用抗免疫复合物抗体的数字免疫分析方法，该抗体特异性识别小分子与抗体的免疫复合物。使用DFM在单个纳米颗粒水平上计数与雌二醇和抗雌二醇抗体的免疫复合物结合的抗免疫复合物抗体修饰的AuNP的数量。我们首次证明，可以使用DFM和抗免疫复合物抗体通过数字免疫测定法检测雌二醇分子，检测灵敏度为1pg/mL。
