The New Zealand Institute for Plant & Food Research Limited, 120 Mt Albert Road, Auckland 1025, New Zealand; The University of Auckland, 20 Symonds Street, Auckland 1010, New Zealand.
The University of Auckland, 20 Symonds Street, Auckland 1010, New Zealand; Digital Sensing Limited, 9C Beatrice-Tinsley Crescent, Auckland 0632, New Zealand.
Talanta. 2019 Jun 1;198:350-357. doi: 10.1016/j.talanta.2019.02.035. Epub 2019 Feb 8.
Ultrasensitive Surface Plasmon Resonance (SPR) detection of small molecules can be achieved using nanoparticles to both enhance the SPR signals and pre-concentrate low levels of target analytes in the sample. However, the short effective penetration depth of the SPR evanescent field, and steric hindrance of binding when immobilizing small molecules on surfaces, limits the applicability of using relatively large nanoparticles (≥100 nm) for SPR detection. To overcome the issues of steric hindrance, this paper investigates the role of the molecular linkers to tether both the antibodies to the magnetic nanoparticles, and to bind the small molecules to the surface of the SPR chips. By extending the distance of the small molecule (progesterone) away from the SPR chip surface and improving the antibody orientation on the large magnetic nanoparticles, a sensitive SPR detection for progesterone was achieved in buffer (0.013 ng mL). The results of the SPR assay for progesterone in milk were in good correlation with ELISA results, and could be used to verify the onset of estrus in cows.
利用纳米粒子既能增强表面等离子体共振（SPR）信号，又能对低浓度的目标分析物进行预浓缩，从而实现对小分子的超灵敏 SPR 检测。然而，SPR 消逝场的有效穿透深度较短，以及小分子在表面固定时的空间位阻限制了相对较大的纳米粒子（≥100nm）在 SPR 检测中的应用。为了克服空间位阻的问题，本文研究了分子接头的作用，将抗体连接到磁性纳米粒子上，并将小分子连接到 SPR 芯片的表面。通过将小分子（孕酮）与 SPR 芯片表面的距离延长，并改善大磁性纳米粒子上的抗体取向，从而实现了在缓冲液中对孕酮的灵敏 SPR 检测（0.013ngmL）。SPR 法测定牛奶中孕酮的结果与 ELISA 结果相关性良好，可用于验证奶牛发情的开始。
