Nanoprobe-Initiated Enzymatic Polymerization for Highly Sensitive Electrochemical DNA Detection
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- 作者：Ying Wan ; Pengjuan Wang ; Yan Su ; Lihua Wang ; Dun Pan ; Ali Aldalbahi ; Shulin Yang ; Xiaolei Zuo
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2015
- 出版时间：November 25, 2015
- 年：2015
- 卷：7
- 期：46
- 页码：25618-25623
- 全文大小：345K
- ISSN：1944-8252
文摘
Electrochemical DNA (E-DNA) sensors have been greatly developed and play an important role in early diagnosis of different diseases. To determine the extremely low abundance of DNA biomarkers in clinical samples, scientists are making unremitting efforts toward achieving highly sensitive and selective E-DNA sensors. Here, a novel E-DNA sensor was developed taking advantage of the signal amplification efficiency of nanoprobe-initiated enzymatic polymerization (NIEP). In the NIEP based E-DNA sensor, the capture probe DNA was thiolated at its 3鈥?terminal to be immobilized onto gold electrode, and the nanoprobe was fabricated by 5鈥?thiol-terminated signal probe DNA conjugated gold nanoparticles (AuNPs). Both of the probes could simultaneously hybridize with the target DNA to form a 鈥渟andwich鈥?structure followed by the terminal deoxynucleotidyl transferase (TdT)-catalyzed elongation of the free 3鈥?terminal of DNA on the nanoprobe. During the DNA elongation, biotin labels were incorporated into the NIEP-generated long single-stranded DNA (ssDNA) tentacles, leading to specific binding of avidin modified horseradish peroxidase (Av-HRP). Since there are hundreds of DNA probes on the nanoprobe, one hybridization event would generate hundreds of long ssDNA tentacles, resulting in tens of thousands of HRP catalyzed reduction of hydrogen peroxide and sharply increasing electrochemical signals. By employing nanoprobe and TdT, it is demonstrated that the NIEP amplified E-DNA sensor has a detection limit of 10 fM and excellent differentiation ability for even single-base mismatch.