In this communication, we present an in-depth study of DNA/DNA, DNA/PNA and PNA/PNA hybridisation on a conducting polymer-modified electrode, measured by means of electrochemical impedance spectroscopy (EIS). DNA or PNA nucleic base sequence probes (where DNA stands for deoxyribonucleic acid and PNA for peptide nucleic acid) were covalently attached onto the sensor surface. As PNA is a non-charged variant of DNA, we investigate the effects of the surface charge and surface blocking by the surface confined probe/target nucleic bases complexes onto the kinetics of redox reaction of Fe(CN)₆^3−/4− couple occurring at the electrode/solution interface that provides electrochemical readout for hybridisation. A range of hybridisation detection experiments were performed, where the surface charge and surface charge density were varied, through varying the charged nature of the probe and the target (i.e. PNA or DNA) and the density of surface-bound PNA and DNA probes. To further the understanding of these effects on the measured electrochemical signal, kinetic studies of the hybridisation reactions were undertaken, and the equilibrium binding constants and binding rate constants for the hybridisation reactions were obtained. The study provides valuable insights to guide future designs of biosensors.

中文翻译：

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基于导电聚合物的电化学基因传感中的 PNA与DNA：研究电荷和表面阻断对传感器信号的影响†

在本交流中，我们介绍了在电化学修饰的导电电极上对DNA / DNA，DNA / PNA和PNA / PNA杂交的深入研究，通过电化学阻抗谱（EIS）进行了测量。将DNA或PNA核酸碱基序列探针（其中DNA代表脱氧核糖核酸，PNA代表肽核酸）共价连接到传感器表面。由于PNA是DNA的不带电变体，因此我们研究了表面受限探针/目标核酸碱基复合物对表面电荷和表面的阻断对Fe（CN）₆ ^{3- / 4-}的氧化还原反应动力学的影响在电极/溶液界面发生的电偶耦合为杂交提供了电化学读数。进行了一系列杂交检测实验，其中通过改变探针和靶标（即PNA或DNA）的带电性质以及表面结合的PNA和DNA探针的密度来改变表面电荷和表面电荷密度。为了进一步理解这些对测量的电化学信号的影响，进行了杂交反应的动力学研究，并获得了杂交反应的平衡结合常数和结合速率常数。该研究提供了宝贵的见识，可指导生物传感器的未来设计。