Department of Chemical and Biomolecular Engineering.
ACS Nano. 2009 Jul 28;3(7):1823-30. doi: 10.1021/nn9004632. Epub 2009 Jul 7.
Other than concentrating the target molecules at the sensor location, we demonstrate two distinct new advantages of an open-flow impedance-sensing platform for DNA hybridization on carbon nanotube (CNT) surface in the presence of a high-frequency AC electric field. The shear-enhanced DNA and ion transport rate to the CNT surface decouples the parasitic double-layer AC impedance signal from the charge-transfer signal due to DNA hybridization. The flow field at high AC frequency also amplifies the charge-transfer rate across the hybridized CNT and provides shear-enhanced discrimination between DNA from targeted species and a closely related congeneric species with three nucleotide mismatches out of 26 bases in a targeted attachment region. This allows sensitive detection of hybridization events in less than 20 min with picomolar target DNA concentrations in a label-free CNT-based microfluidic detection platform.
除了将目标分子集中在传感器位置，我们还展示了在高频交流电场存在下，开放式流动阻抗传感平台在碳纳米管（CNT）表面用于 DNA 杂交的两个明显的新优势。由于 DNA 杂交，剪切增强的 DNA 和离子向 CNT 表面的传输速率使寄生双层交流阻抗信号与电荷转移信号解耦。在高频交流电下的流场也放大了杂交 CNT 之间的电荷转移速率，并提供了剪切增强的靶向附着区域中 26 个碱基中 3 个核苷酸错配的目标物种与密切相关的同系物之间的区分。这使得在无标记的 CNT 基微流控检测平台中，能够以皮摩尔级的目标 DNA 浓度在不到 20 分钟的时间内实现杂交事件的敏感检测。
