کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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868648 | 909811 | 2009 | 7 صفحه PDF | دانلود رایگان |

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-NH2) 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(NH3)6]3+ 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 × 10−11 to 2.7 × 10−14 mol L−1 and the detection limit was 1.4 × 10−14 mol L−1. The DNA sensor not only showed low detection limit, but also exhibited excellent selectivity against two-base mismatched DNA.
Journal: Biosensors and Bioelectronics - Volume 24, Issue 11, 15 July 2009, Pages 3281–3287