Liu Zhengru, Yang Bin, Chen Beibei, He Man, Hu Bin
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, P R China.
Analyst. 2016 Dec 19;142(1):197-205. doi: 10.1039/c6an01919f.
Upconversion nanoparticles (UCNPs) have received increasing attention due to their unique optical properties. Recognizing that UCNPs are lanthanide-doped nanoparticles, we incorporated UCNPs into an immunoassay with inductively coupled plasma mass spectrometry (ICP-MS) detection for the determination of specific proteins, e.g., alpha-fetoprotein (AFP). The sensitivity of the assay was enhanced because of the ICP-MS detection of UCNPs that contained large numbers of lanthanide elemental tags. Conjugates of UCNPs and antibodies were prepared and the morphology of the conjugates was characterized by transmission electron microscopy. After a sandwich immunoreaction, the AFP was determined by the ICP-MS analysis of UCNPs. Under the optimized conditions, a limit of detection (3σ) of 0.31 ng mL based on Y signal and 0.22 ng mL based on Yb signal was obtained for AFP, with a dynamic range of 0.5-35 ng mL and a relative standard deviation of 4.8% (c = 5 ng mL, n = 9). The developed method was applied to the determination of AFP in human serum and the recovery for the spiked sample was in the range of 98.6-123%. The proposed method is simple, rapid, selective and sensitive, and has a good tolerance for the complex biological matrix, indicating great potential for the application of UCNP in biological research as an elemental tag.
上转换纳米粒子（UCNPs）因其独特的光学性质而受到越来越多的关注。认识到UCNPs是镧系元素掺杂的纳米粒子，我们将UCNPs纳入一种采用电感耦合等离子体质谱（ICP-MS）检测的免疫分析方法中，用于测定特定蛋白质，例如甲胎蛋白（AFP）。由于对含有大量镧系元素标签的UCNPs进行ICP-MS检测，该分析方法的灵敏度得以提高。制备了UCNPs与抗体的缀合物，并通过透射电子显微镜对缀合物的形态进行了表征。经过夹心免疫反应后，通过对UCNPs的ICP-MS分析来测定AFP。在优化条件下，基于Y信号得到的AFP检测限（3σ）为0.31 ng/mL，基于Yb信号的检测限为0.22 ng/mL，动态范围为0.5 - 35 ng/mL，相对标准偏差为4.8%（c = 5 ng/mL，n = 9）。所建立的方法应用于人体血清中AFP的测定，加标样品的回收率在98.6% - 123%范围内。该方法简便、快速、具有选择性且灵敏，对复杂生物基质具有良好的耐受性，表明UCNP作为一种元素标签在生物学研究中的应用具有巨大潜力。
