Azadbakht Azadeh, Roushani Mahmoud, Abbasi Amir Reza, Derikvand Zohreh
Department of Chemistry, Islamic Azad University, Khorramabad Branch, Khorramabad, Iran.
Department of Chemistry, Ilam University, Ilam, Iran.
Anal Biochem. 2016 Aug 15;507:47-57. doi: 10.1016/j.ab.2016.04.022. Epub 2016 May 9.
Here, an ultrasensitive label-free electrochemical aptasensor was developed for dopamine (DA) detection. Construction of the aptasensor was carried out by electrodeposition of gold-platinum nanoparticles (Au-PtNPs) on glassy carbon (GC) electrode modified with acid-oxidized carbon nanotubes (CNTs-COOH). A designed complementary amine-capped capture probe (ssDNA1) was immobilized at the surface of PtNPs/CNTs-COOH/GC electrode through the covalent amide bonds formed by the carboxyl groups on the nanotubes and the amino groups on the oligonucleotides. DA-specific aptamer was attached onto the electrode surface through hybridization with the ssDNA1. Methylene blue (MB) was used as an electrochemical indicator that was intercalated into the aptamer through the specific interaction with its guanine bases. In the presence of DA, the interaction between aptamer and DA displaced the MB from the electrode surface, rendering a lowered electrochemical signal attributed to a decreased amount of adsorbed MB. This phenomenon can be applied for DA detection. The peak current of probe (MB) linearly decreased over a DA concentration range of 1-30 nM with a detection limit of 0.22 nM.
在此，开发了一种用于检测多巴胺（DA）的超灵敏无标记电化学适体传感器。该适体传感器的构建是通过在经酸氧化的碳纳米管（CNTs-COOH）修饰的玻碳（GC）电极上电沉积金铂纳米颗粒（Au-PtNPs）来实现的。通过纳米管上的羧基与寡核苷酸上的氨基形成的共价酰胺键，将设计好的互补胺封端捕获探针（ssDNA1）固定在PtNPs/CNTs-COOH/GC电极表面。DA特异性适体通过与ssDNA1杂交附着在电极表面。亚甲基蓝（MB）用作电化学指示剂，通过与适体的鸟嘌呤碱基的特异性相互作用插入到适体中。在存在DA的情况下，适体与DA之间的相互作用将MB从电极表面置换出来，导致由于吸附的MB量减少而使电化学信号降低。这种现象可用于DA检测。探针（MB）的峰值电流在1-30 nM的DA浓度范围内呈线性下降，检测限为0.22 nM。
