School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Nanoscale. 2014 Mar 21;6(6):3110-5. doi: 10.1039/c3nr05625b. Epub 2014 Feb 3.
A sensitive electrochemical DNA biosensor based on the amplification of Au nanoparticles (AuNPs) has been developed. The AuNPs were modified with two types of signaling reporter DNAs, i.e. a methylene blue probe (MB-probe 2-SH) and T10 with a methylene blue signaling molecule (MB-T10-SH), forming DNA-AuNP conjugates. The MB-probe 2-SH is complementary to the target DNA, while MB-T10-SH is not. The presence of MB-T10-SH reduces the cross-reaction between target DNA and MB-probe 2-SH on the AuNPs, resulting in increased sensitivity of the biosensor. In our assay, the DNA sensor is fabricated by immobilizing a capture probe on the surface of the Au electrode, which then hybridizes with the corresponding target DNA, and further hybridizes with a DNA-Au conjugate. The signal of MB is measured by differential pulse voltammetry, while the DNA-Au conjugate enables the detection of target DNA in the linear range of 10(-13) to 10(-8) M with the detection limit as low as 50 fM.
基于金纳米粒子 (AuNPs) 放大作用的灵敏电化学 DNA 生物传感器已被开发出来。AuNPs 用两种类型的信号报告 DNA 进行修饰，即亚甲基蓝探针 (MB-probe 2-SH) 和带有亚甲基蓝信号分子 (MB-T10-SH) 的 T10，形成 DNA-AuNP 缀合物。MB-probe 2-SH 与靶 DNA 互补，而 MB-T10-SH 则不互补。MB-T10-SH 的存在减少了 AuNPs 上靶 DNA 与 MB-probe 2-SH 之间的交叉反应，从而提高了生物传感器的灵敏度。在我们的测定中，通过将捕获探针固定在 Au 电极表面来制备 DNA 传感器，然后与相应的靶 DNA 杂交，然后与 DNA-Au 缀合物杂交。通过差分脉冲伏安法测量 MB 的信号，而 DNA-Au 缀合物能够在 10(-13) 到 10(-8) M 的线性范围内检测到靶 DNA，检测限低至 50 fM。
