College of Life Science, Dalian Minzu University, Dalian, Liaoning 116600, China.
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Langmuir. 2024 Sep 17;40(37):19839-19845. doi: 10.1021/acs.langmuir.4c02763. Epub 2024 Sep 3.
Label-free gold nanoparticle (AuNP)-based colorimetric biosensors have been widely used for the detection of DNA. However, the effect of the biological sample matrix has not been fully explored. In this work, we investigated the salt-induced aggregation of AuNPs as well as DNA adsorption in serum and milk. AuNPs of 13, 30, and 50 nm were used as probes. The detection was successful only in a clean buffer but failed in serum or milk. Serum and milk exhibited excellent protective properties, even 250 mM NaCl added did not induce the aggregation of AuNPs. After centrifugation of milk, the supernatant did not protect the AuNPs, whereas the redispersed pellet showed protection. The limit concentration of serum to prevent AuNPs from aggregating was 0.04% for 13 nm AuNPs and 0.01% serum for 50 nm AuNPs. In addition, serum reduced DNA adsorption, and the DNA was adsorbed to the protein corona instead of directly to the AuNP surface. These two factors can explain the difficulty of detection in protein-containing samples. This study articulates the adsorption of proteins by AuNPs in biological samples and offers useful insights into the biosensor design.
无标记金纳米粒子 (AuNP) 比色生物传感器已广泛用于检测 DNA。然而，生物样品基质的影响尚未得到充分研究。在这项工作中，我们研究了 AuNP 在血清和牛奶中盐诱导聚集以及 DNA 吸附的情况。使用了 13、30 和 50nm 的 AuNP 作为探针。仅在清洁缓冲液中检测成功，但在血清或牛奶中检测失败。血清和牛奶表现出优异的保护性能，即使添加 250mM NaCl 也不会诱导 AuNP 聚集。离心牛奶后，上清液不能保护 AuNP，而重新分散的沉淀则具有保护作用。血清防止 13nm AuNP 聚集的极限浓度为 0.04%，50nm AuNP 的血清极限浓度为 0.01%。此外，血清减少了 DNA 的吸附，DNA 被吸附到蛋白质冠上，而不是直接吸附到 AuNP 表面。这两个因素可以解释在含蛋白质的样品中检测困难的原因。本研究阐明了 AuNP 在生物样品中的蛋白质吸附，并为生物传感器设计提供了有用的见解。
