Zhou Zhixin, Wei Wei, Zhang Yuanjian, Liu Songqin
State Key Laboratory of Bioelectronics, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P.R. China.
J Mater Chem B. 2013 Jun 14;1(22):2851-2858. doi: 10.1039/c3tb20206b. Epub 2013 May 3.
Due to great potential in nanobiotechnology, nanomachines, and smart materials, DNA-directed disassembly of gold nanoparticles (AuNPs) has been extensively explored. In a typical system, nonbase-paired regions (e.g., overhangs and gaps in the linker DNA and oligonucleotide spacers between thiol group and hybridization sequence) are indispensable portions in the disassembly of AuNPs based on DNA displacement reaction. Therefore, it is necessary to study the effect of nonbase-paired regions to improve the kinetics of disassembly of AuNPs. Herein, the disassembly rate of AuNPs based on DNA displacement reaction was investigated by using different length spacers and linker DNA containing various lengths of gaps or overhangs. Interestingly, it was revealed that among the gaps in the linker DNA could be most effectively used to improve the disassembly rate of the AuNPs. As a result, when we introduced gaps into linker DNA, the DNA displacement reaction of AuNPs was markedly shortened to less than 50 min, which was much faster than the previous methods. As a proof of the importance of our findings, a rapid AuNP-based colorimetric DNA biosensor has been successfully prepared. In addition, we showed that the signal of the biosensors could be further amplified using exonuclease III, resulting in a much lower detection limit in comparison with previous sensors similarly using AuNP aggregates as probes.
由于在纳米生物技术、纳米机器和智能材料方面具有巨大潜力，基于DNA的金纳米颗粒（AuNPs）拆卸技术已得到广泛研究。在典型体系中，非碱基配对区域（如连接DNA中的突出端和间隙以及硫醇基团与杂交序列之间的寡核苷酸间隔区）是基于DNA置换反应拆卸AuNPs时不可或缺的部分。因此，有必要研究非碱基配对区域的影响，以改善AuNPs的拆卸动力学。在此，通过使用不同长度的间隔区和含有不同长度间隙或突出端的连接DNA，研究了基于DNA置换反应的AuNPs拆卸速率。有趣的是，结果表明连接DNA中的间隙能最有效地用于提高AuNPs的拆卸速率。因此，当我们在连接DNA中引入间隙时，AuNPs的DNA置换反应显著缩短至不到50分钟，这比以前的方法快得多。作为我们研究结果重要性的证明，已成功制备了一种基于AuNP的快速比色DNA生物传感器。此外，我们表明使用核酸外切酶III可进一步放大生物传感器的信号，与同样使用AuNP聚集体作为探针的先前传感器相比，检测限更低。
