Ghanbari Kh, Bathaie S Z, Mousavi M F
Department of Chemistry, Tarbiat Modares University, Tehran, Iran.
Biosens Bioelectron. 2008 Jul 15;23(12):1825-31. doi: 10.1016/j.bios.2008.02.029. Epub 2008 Mar 18.
A new biosensor employing immobilized DNA on a nano-structured conductive polymer fixed onto a platinum electrode is presented. Upon optimization of synthesis parameters, polypyrrole nanofibers, 30-90 nm in diameter, were synthesized in an aqueous media by the electropolymerization of pyrrole using normal pulse voltammetry (NPV). The nanofiber film was investigated by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Double-stranded DNA was physisorbed onto the PPy nanofiber films. Various parameters, including the pH and DNA concentration, were optimized. The DNA immobilized on the nanofiber films was characterized using differential pulse voltammetry (DPV) and Fourier-transform infrared (FTIR) spectroscopy. Using DPV to study the interaction of spermidine with DNA, a binding constant (K) value of 4.08 x 10(5)+/-0.05 M(-1) was obtained. For the determination of spermidine, the proposed method exhibited a good dynamic range, correlation coefficient (0.05-1.0 microM and 0.9983, respectively) and a low detection limit (0.02 microM), although Ca(2+) ions were found to electrostatically bind to DNA and weaken the spermidine-DNA interaction.
介绍了一种新型生物传感器，该传感器将固定在铂电极上的纳米结构导电聚合物上的固定化DNA作为检测元件。通过优化合成参数，采用常规脉冲伏安法（NPV）在水性介质中通过吡咯的电聚合反应合成了直径为30-90nm的聚吡咯纳米纤维。通过扫描电子显微镜（SEM）、循环伏安法（CV）和电化学阻抗谱（EIS）对纳米纤维膜进行了研究。双链DNA通过物理吸附作用吸附在聚吡咯纳米纤维膜上。对包括pH值和DNA浓度在内的各种参数进行了优化。使用差分脉冲伏安法（DPV）和傅里叶变换红外（FTIR）光谱对固定在纳米纤维膜上的DNA进行了表征。利用DPV研究亚精胺与DNA的相互作用，得到结合常数（K）值为4.08×10⁵±0.05 M⁻¹。对于亚精胺的测定，尽管发现Ca²⁺离子会与DNA发生静电结合并削弱亚精胺与DNA的相互作用，但所提出的方法仍具有良好的动态范围、相关系数（分别为0.05-1.0 μM和0.9983）以及较低的检测限（0.02 μM）。
