Polymer Electronics Research Centre, School of Chemical Sciences, University of Auckland, 23 Symonds Street, Auckland, New Zealand.
Analyst. 2018 Feb 7;143(3):687-694. doi: 10.1039/c7an01590a. Epub 2018 Jan 3.
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) 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.
在本通讯中，我们通过电化学阻抗谱（EIS）研究了在导电聚合物修饰电极上的 DNA/DNA、DNA/PNA 和 PNA/PNA 杂交，深入研究了 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）在传感器表面的共价附着。由于 PNA 是 DNA 的非带电变体，我们研究了表面电荷和表面被表面限制的探针/靶核酸碱基复合物的阻断对发生在电极/溶液界面处的 Fe(CN) 对氧化还原反应动力学的影响，该界面提供了杂交的电化学读出。进行了一系列杂交检测实验，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。为了进一步了解这些对测量电化学信号的影响，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。该研究为指导未来生物传感器的设计提供了有价值的见解。
