College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
Analyst. 2011 Oct 21;136(20):4204-10. doi: 10.1039/c1an15526a. Epub 2011 Aug 24.
This work developed a relatively inexpensive and layers-film construction electrochemical sensor for DNA recognition and its performance was investigated. The Fe(3)O(4) magnetic nanoparticles-cysteine were immobilized on the carbon paste electrode (CPE) surface using magnetic force. Multiwalled carbon nanotubes (MWCNTs), gold nanoparticles (GNPs), and chitosan (Chi) were used successively to coat on the electrode surface. The thiolated capture probe was assembled and competitively hybridized with the target nucleic acid and biotinylated response probe. The electrochemical behavior was analyzed by cyclic voltammetry and electrochemical impedance spectroscopy. In addition, the sensor performance was also analyzed by introducing the notion of detection efficiency. The experimental results showed that although the electron transfer capability of the CPE is less strong than that of a metal electrode used in the DNA sensor, the materials modified on the CPE could significantly improve the performance. A detection limit of 1 nM of target DNA and a sensitivity of 2.707 × 10(3) mA M(-1) cm(-2) were obtained. Although the resulting detection limit was not remarkable, further experiments could improve it.
这项工作开发了一种相对廉价且具有多层膜结构的电化学传感器，用于 DNA 识别，并对其性能进行了研究。通过磁力将 Fe(3)O(4)磁性纳米粒子-半胱氨酸固定在碳糊电极（CPE）表面上。然后依次将多壁碳纳米管（MWCNTs）、金纳米粒子（GNPs）和壳聚糖（Chi）涂覆在电极表面上。将巯基化的捕获探针组装并与靶核酸进行竞争性杂交，然后与生物素化的响应探针杂交。通过循环伏安法和电化学阻抗谱分析了电化学行为。此外，还通过引入检测效率的概念来分析传感器的性能。实验结果表明，尽管 CPE 的电子转移能力不如 DNA 传感器中使用的金属电极强，但 CPE 上修饰的材料可以显著提高性能。获得了 1 nM 的目标 DNA 的检测限和 2.707×10(3) mA M(-1) cm(-2)的灵敏度。尽管得到的检测限并不显著，但进一步的实验可以提高它。
