Institute of Quality Standards and Testing Technology for Agro-products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China.
Biosens Bioelectron. 2014 Feb 15;52:265-70. doi: 10.1016/j.bios.2013.08.059. Epub 2013 Sep 9.
Gold nanoparticles (AuNPs) based fluorescence quenching or colorimetric aptasensor have been developed for many analytes recently largely because of the ease of detection, high sensitivity, and potential for high-throughput analysis. However, the effects of remnant non-AuNPs components in the colloid gold solution on these assays performance remain unclear. For the first time, we demonstrated that the remnant sodium citrate and the reaction products of three acids play counteractive roles in AuNPs based fluorescence quenching and colorimetric aptasensor in three ways in this study. First, the remnant sodium citrate in the colloid gold solution could increase the fluorescence intensity of FAM labeled on the aptamer that reduce the efficiency of AuNPs fluorescent quenching. Second, the reaction products of citric acid, HCl and ketoglutaric acid reduce the fluorescence recovery by quenching the fluorescence of FAM labeled on the aptamer dissociated from the surface of AuNPs upon addition of target. Lastly, the reaction products of three acids reduce the pH value of the colloid gold solution that reduce the sensitivity of AuNPs based colorimetric aptasensor by increasing the adsorption of aptamer to surface of AuNPs. With sulfadimethoxine and thrombin as model analytes, we found that water resuspended AuNPs can significantly increase the sensitivity by more than 10-fold for AuNPs based fluorescence quenching aptasensor. In the AuNPs based colorimetric aptasensor for sulfadimethoxine using the water resuspended AuNPs, the sensitivity also was increased by 10-fold compared with that of original AuNPs. The findings in this study provide theoretical guidance for further improving AuNPs based fluorescent quenching and colorimetric aptasensor by adjusting the composition of AuNPs solution.
基于金纳米粒子（AuNPs）的荧光猝灭或比色适体传感器最近已被广泛用于多种分析物，主要是因为其检测方便、灵敏度高且具有高通量分析的潜力。然而，胶体金溶液中残留的非 AuNPs 成分对这些分析物性能的影响仍不清楚。在这项研究中，我们首次证明，胶体金溶液中的残留柠檬酸钠和三种酸的反应产物以三种方式在基于 AuNPs 的荧光猝灭和比色适体传感器中发挥拮抗作用。首先，胶体金溶液中的残留柠檬酸钠可以增加与适体结合的 FAM 的荧光强度，从而降低 AuNPs 荧光猝灭的效率。其次，柠檬酸、盐酸和酮戊二酸的反应产物通过猝灭与 AuNPs 表面解离的 FAM 标记的适体的荧光来减少荧光恢复。最后，三种酸的反应产物降低胶体金溶液的 pH 值，通过增加适体对 AuNPs 表面的吸附，降低基于 AuNPs 的比色适体传感器的灵敏度。以磺胺二甲氧嘧啶和凝血酶为模型分析物，我们发现水重悬的 AuNPs 可使基于 AuNPs 的荧光猝灭适体传感器的灵敏度提高 10 倍以上。在使用水重悬的 AuNPs 的磺胺二甲氧嘧啶的基于 AuNPs 的比色适体传感器中，与原始 AuNPs 相比，灵敏度也提高了 10 倍。本研究的结果为通过调整 AuNPs 溶液的组成进一步改进基于 AuNPs 的荧光猝灭和比色适体传感器提供了理论指导。
