College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, Guangdong, China.
State Key Laboratory of Heavy Oil Processing and College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, Shandong, China.
Nano Lett. 2021 Jul 14;21(13):5532-5539. doi: 10.1021/acs.nanolett.1c00830. Epub 2021 Jun 17.
Exosomes are often a promising source of biomarkers for cancer diagnosis in the early stages. Therefore, it is important to develop a sensitive and low-cost detection method. Here, we introduce a new substrate using gold nanorods (GNRs) on a silver-island film that produces a 360-fold AF647 molecule fluorescence enhancement compared to glass. The amplified fluorescence was proven theoretically by using finite difference time-domain simulation (FDTD). Utilizing the enhanced fluorescence from the substrate, GNRs attached with the biomolecules and created a sandwich immunoassay that can significantly detect human CD63 antigen on the exosome. By applying the method, the detection limit of mouse IgG goes down to 0.3 ng/mL, which is considerably better than the existing methods. Moreover, the sensitivity and accuracy for clinical plasma from six patients confirm its diagnostic feasibility. The proposed substrate can be uniformly extended to the identification of other biomarkers by modifying the antibodies on the surfaces of the GNRs.
外泌体通常是癌症早期诊断有前景的生物标志物来源。因此，开发一种灵敏且低成本的检测方法很重要。在这里，我们介绍了一种使用金纳米棒（GNRs）在银岛膜上的新型基底，与玻璃相比，该基底使 AF647 分子的荧光增强了 360 倍。通过使用有限差分时域模拟（FDTD）对放大的荧光进行了理论验证。利用基底的增强荧光，将附着有生物分子的 GNRs 用于夹心免疫测定，可显著检测外泌体上的人 CD63 抗原。通过应用该方法，可将小鼠 IgG 的检测下限降低至 0.3ng/mL，明显优于现有方法。此外，对来自六位患者的临床血浆的灵敏度和准确性验证了其诊断的可行性。通过修饰 GNRs 表面的抗体，可将该基底均匀地扩展到其他生物标志物的识别。
