Biomedical Diagnostics Institute, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
Biosens Bioelectron. 2011 Jan 15;26(5):2613-8. doi: 10.1016/j.bios.2010.11.017. Epub 2010 Nov 19.
Polyaniline (PANI) nanofibres (PANI-NF) have been modified with chemically grown gold nanoparticles to give a nanocomposite material (PANI-NF-AuNP) and deposited on gold electrodes. Single stranded capture DNA was then bound to the gold nanoparticles and the underlying gold electrode and allowed to hybridise with a complementary target strand that is uniquely associated with the pathogen, Staphylococcus aureus (S. aureus), that causes mastitis. Significantly, cyclic voltammetry demonstrates that deposition of the gold nanoparticles increases the area available for DNA immobilisation by a factor of approximately 4. EPR reveals that the addition of the Au nanoparticles efficiently decreases the interactions between adjacent PANI chains and/or motional broadening. Finally, a second horseradish peroxidase (HRP) labelled DNA strand hybridises with the target allowing the concentration of the target DNA to be detected by monitoring the reduction of a hydroquinone mediator in solution. The sensors have a wide dynamic range, excellent ability to discriminate DNA mismatches and a high sensitivity. Semi-log plots of the pathogen DNA concentration vs. faradaic current were linear from 150×10(-12) to 1×10(-6) mol L(-1) and pM concentrations could be detected without the need for molecular, e.g., PCR or NASBA, amplification.
聚苯胺（PANI）纳米纤维（PANI-NF）经过化学生长的金纳米粒子修饰，得到纳米复合材料（PANI-NF-AuNP），并沉积在金电极上。然后，将单链捕获 DNA 结合到金纳米粒子和下面的金电极上，并允许与唯一与病原体金黄色葡萄球菌（S. aureus）相关的互补靶链杂交，金黄色葡萄球菌会引起乳腺炎。重要的是，循环伏安法表明，金纳米粒子的沉积使 DNA 固定的可用面积增加了约 4 倍。EPR 表明，添加 Au 纳米粒子可有效降低相邻 PANI 链之间的相互作用和/或运动展宽。最后，第二个辣根过氧化物酶（HRP）标记的 DNA 链与靶标杂交，通过监测溶液中氢醌介体的还原，可以检测到靶标 DNA 的浓度。该传感器具有宽的动态范围、出色的区分 DNA 错配的能力和高灵敏度。病原体 DNA 浓度与法拉第电流的半对数图呈线性关系，从 150×10(-12) 到 1×10(-6) mol L(-1)，并且可以在不需要分子（例如 PCR 或 NASBA）扩增的情况下检测到 pM 浓度。
