Li Xiaoxia, Shen Lihua, Zhang Dongdong, Qi Honglan, Gao Qiang, Ma Fen, Zhang Chengxiao
School of Chemistry and Materials Science, Shaanxi Normal University, Xi'an 710062, People's Republic of China.
Biosens Bioelectron. 2008 Jun 15;23(11):1624-30. doi: 10.1016/j.bios.2008.01.029. Epub 2008 Feb 8.
A simple and highly sensitive electrochemical impedance spectroscopy (EIS) biosensor based on a thrombin-binding aptamer as molecular recognition element was developed for the determination of thrombin. The signal enhancement was achieved by using gold nanoparticles (GNPs), which was electrodeposited onto a glassy carbon electrode (GCE), as a platform for the immobilization of the thiolated aptamer. In the measurement of thrombin, the change in interfacial electron transfer resistance of the biosensor using a redox couple of Fe(CN)(6) as the probe was monitored. The increase of the electron transfer resistance of the biosensor is linear with the concentration of thrombin in the range from 0.12nM to 30nM. The association and dissociation rate constants of the immobilized aptamer-thrombin complex were 6.7x10(3)M(-1)s(-1) and 1.0x10(-4)s(-1), respectively. The association and dissociation constants of three different immobilized aptamers binding with thrombin were measured and the difference of the dissociation constants obtained was discussed. This work demonstrates that GNPs electrodeposited on GCE used as a platform for the immobilization of the thiolated aptamer can improve the sensitivity of an EIS biosensor for the determination of protein. This work also demonstrates that EIS method is an efficient method for the determination of association and dissociation constants on GNPs modified GCE.
开发了一种基于凝血酶结合适体作为分子识别元件的简单且高灵敏度的电化学阻抗谱（EIS）生物传感器，用于测定凝血酶。通过使用电沉积在玻碳电极（GCE）上的金纳米颗粒（GNP）作为固定硫醇化适体的平台来实现信号增强。在凝血酶的测量中，监测了使用Fe(CN)(6)氧化还原对作为探针的生物传感器界面电子转移电阻的变化。生物传感器电子转移电阻的增加与凝血酶浓度在0.12nM至30nM范围内呈线性关系。固定化适体 - 凝血酶复合物的缔合和解离速率常数分别为6.7x10(3)M(-1)s(-1)和1.0x10(-4)s(-1)。测量了三种不同固定化适体与凝血酶结合的缔合和解离常数，并讨论了所得解离常数的差异。这项工作表明，电沉积在GCE上的GNP用作固定硫醇化适体的平台可以提高EIS生物传感器测定蛋白质的灵敏度。这项工作还表明，EIS方法是测定GNP修饰GCE上缔合和解离常数的有效方法。
