Li Guangjiu, Li Xiaolin, Wan Jun, Zhang Shusheng
Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Biosens Bioelectron. 2009 Jul 15;24(11):3281-7. doi: 10.1016/j.bios.2009.04.022. Epub 2009 Apr 24.
A novel and sensitive electrochemical approach for sequence-specific DNA detection based on polyamidoamine (PAMAM) and signal amplification with nanoparticles (NPs) is reported. A gold electrode was first modified with 3-mercaptopropionic acid, and then reacted with an amino-terminated polyamidoamine (PAMAM, G 4.0-NH(2)) to obtain a thin film. Single-stranded 3'-biotin end-labeled oligonucleotide was immobilized onto the film to obtain a stable recognition layer through biotin-avidin combination to detect complementary target, using signal amplification with Au NPs and Ru(NH(3))(6) as redox electroactive indicators. The properties of the avidin/PAMAM/3-mercaptopropionic acid (RSH)/Au, the characteristics of the immobilization and hybridization of DNA were studied by cyclic voltammetry (CV), difference pulse voltammetry (DPV) and electrochemical impedance spectroscopy. The dynamic detection range of the sequence-specific DNA was from 1.4 x 10(-11) to 2.7 x 10(-14) mol L(-1) and the detection limit was 1.4 x 10(-14) mol L(-1). The DNA sensor not only showed low detection limit, but also exhibited excellent selectivity against two-base mismatched DNA.
报道了一种基于聚酰胺-胺（PAMAM）和纳米颗粒（NPs）信号放大的新型灵敏电化学方法用于序列特异性DNA检测。首先用3-巯基丙酸修饰金电极，然后与氨基端聚酰胺-胺（PAMAM，G 4.0-NH(2)）反应得到薄膜。将3'-生物素末端标记的单链寡核苷酸固定在该薄膜上，通过生物素-抗生物素蛋白结合获得稳定的识别层，以检测互补靶标，使用金纳米颗粒和Ru(NH(3))(6)作为氧化还原电活性指示剂进行信号放大。通过循环伏安法（CV）、差分脉冲伏安法（DPV）和电化学阻抗谱研究了抗生物素蛋白/PAMAM/3-巯基丙酸（RSH）/金的性质、DNA的固定和杂交特性。序列特异性DNA的动态检测范围为1.4×10(-11)至2.7×10(-14) mol L(-1)，检测限为1.4×10(-14) mol L(-1)。该DNA传感器不仅检测限低，而且对两碱基错配DNA表现出优异的选择性。
