Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo, Tokyo 112-8681, Japan.
Analyst. 2019 Sep 9;144(18):5580-5588. doi: 10.1039/c9an00822e.
We previously reported that fully complementary DNA duplexes formed on gold nanoparticle (GNP) surfaces aggregate at high salt concentrations. We previously reported that DNA-functionalized gold nanoparticles (GNPs) aggregate by hybridization with fully complementary DNA at high salt concentrations. Although this behavior has been applied to some precise naked-eye colorimetric analyses of DNA-related molecules, the aggregation mechanism is still unclear and comprehensive studies are needed. In this paper, we reveal the key factors that influence GNP aggregation. The effects of temperature, electrolyte concentration, probe length, and particle size, which control the stabilities of double-stranded DNAs and GNPs, were investigated. Larger GNPs aggregated more easily, and GNP aggregates were easily formed with ∼15-mer-long probes, while longer probes prevented aggregation, perhaps by preventing the formation of rigid double-stranded DNA layers, compared to shorter probes. Furthermore, GNPs with purine bases at their 5' ends aggregated more easily than those with these bases at their 3' ends. This phenomenon is different from that based on the melting-temperature trend calculated using the nearest-neighbor method.
我们之前曾报道过，在高盐浓度下，完全互补的 DNA 双链在金纳米粒子 (GNP) 表面形成并聚集。我们之前曾报道过，在高盐浓度下，通过与完全互补的 DNA 杂交，DNA 功能化的金纳米粒子 (GNPs) 会聚集。虽然这种行为已经应用于一些对与 DNA 相关的分子进行精确的肉眼比色分析，但聚集机制仍不清楚，需要进行全面的研究。在本文中，我们揭示了影响 GNP 聚集的关键因素。研究了温度、电解质浓度、探针长度和颗粒大小对双链 DNA 和 GNPs 稳定性的影响。较大的 GNPs 更容易聚集，而约 15 个碱基长的探针更容易形成 GNP 聚集体，而较长的探针则可能通过防止形成刚性双链 DNA 层来阻止聚集，而较短的探针则更容易聚集。此外，与这些碱基位于 3' 端的 GNP 相比，位于 5' 端的 GNP 更容易聚集。这种现象与使用最近邻方法计算的熔解温度趋势的现象不同。
