石墨烯
电极
微分脉冲伏安法
材料科学
纳米片
生物传感器
检出限
电化学
电泳沉积
石墨
分析化学(期刊)
鸟嘌呤
寡核苷酸
循环伏安法
纳米技术
DNA
化学
核苷酸
色谱法
复合材料
生物化学
物理化学
基因
涂层
作者
Omid Akhavan,Elham Ghaderi,Reza Rahighi
出处
期刊:ACS Nano
[American Chemical Society]
日期:2012-03-14
卷期号:6 (4): 2904-2916
被引量:413
摘要
Graphene oxide nanowalls with extremely sharp edges and preferred vertical orientation were deposited on a graphite electrode by using electrophoretic deposition in an Mg(2+)-GO electrolyte. Using differential pulse voltammetry (DPV), reduced graphene nanowalls (RGNWs) were applied for the first time, in developing an ultra-high-resolution electrochemical biosensor for detection of the four bases of DNA (G, A, T, and C) by monitoring the oxidation signals of the individual nucleotide bases. The extremely enhanced electrochemical reactivity of the four free bases of DNA, single-stranded DNA, and double-stranded DNA (dsDNA) at the surface of the RGNW electrode was compared to electrochemical performances of reduced graphene nanosheet (RGNS), graphite, and glassy carbon electrodes. By increasing the number of DPVs up to 100 scans, the RGNW electrode exhibited an excellent stability with only 15% variation in the oxidation signals, while for the RGNS electrode no detectable signals relating to T and C of 0.1 μM dsDNA were observed. The linear dynamic detection range of the RGNW electrode for dsDNA was checked in the wide range of 0.1 fM to 10 mM, while for the RGNS electrode, it was from 2.0 pM to <10 mM. The lower limits of dsDNA detection of the RGNW and RGNS electrodes were estimated as 9.4 zM (∼5 dsDNA/mL) and 5.4 fM, respectively. The RGNWs were efficient in label-free detection of single nucleotide polymorphisms of 20 zM oligonucleotides (∼10 DNA/mL) having a specific sequence. Therefore, the RGNWs can effectively contribute to the development of ultra-high-sensitive electrochemical biosensors with single-DNA resolutions.
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