Nanobioelectronics & Biosensors Group, Catalan Institute of Nanotechnology, 08193, Bellaterra, Barcelona, Spain.
Anal Chem. 2012 Aug 7;84(15):6821-7. doi: 10.1021/ac301369e. Epub 2012 Jul 9.
The performance of cadmium-selenide/zinc-sulfide (CdSe@ZnS) quantum dots (QDs) and the fluorescent dye Alexa 647 as reporter in an assay designed to detect apolipoprotein E (ApoE) has been compared. The assay is a sandwich immunocomplex microarray that functions via excitation by visible light. ApoE was chosen for its potential as a biomarker for Alzheimer's disease. The two versions of the microarray (QD or Alexa 647) were assessed under the same experimental conditions and then compared to a conventional enzyme-linked immunosorbent assay (ELISA) targeting ApoE. The QDs proved to be highly effective reporters in the microarrays, although their performance strongly varied in function of the excitation wavelength. At 633 nm, the QD microarray gave a limit of detection (LOD) of 247 pg mL(-1); however, at an excitation wavelength of 532 nm, it provided a LOD of ~62 pg mL(-1), five times more sensitive than that of the Alexa microarray (307 pg mL(-1)) and seven times more than that of the ELISA (~470 pg mL(-1)). Finally, serial dilutions from a human serum sample were assayed with high sensitivity and acceptable precision and accuracy.
我们比较了碲化镉/硫化锌（CdSe@ZnS）量子点（QDs）和荧光染料 Alexa 647 作为用于检测载脂蛋白 E（ApoE）的分析物的报告分子的性能。该分析物是一种夹心免疫复合物微阵列，通过可见光激发来检测。选择 ApoE 作为生物标志物，是因为其在阿尔茨海默病方面的潜在应用。在相同的实验条件下评估了这两种微阵列（QD 或 Alexa 647），然后将其与针对 ApoE 的传统酶联免疫吸附测定（ELISA）进行了比较。结果表明，QD 在微阵列中是非常有效的报告分子，尽管它们的性能强烈依赖于激发波长。在 633nm 时，QD 微阵列的检测限（LOD）约为 247pgmL(-1)；然而，在 532nm 的激发波长下，它提供的 LOD 约为 62pgmL(-1)，比 Alexa 微阵列（307pgmL(-1)）敏感五倍，比 ELISA（470pgmL(-1)）敏感七倍。最后，对来自人血清样本的系列稀释液进行了高灵敏度、可接受的精密度和准确度检测。
