Analytische Chemie-Elektroanalytik & Sensorik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
Chemphyschem. 2010 Sep 10;11(13):2887-95. doi: 10.1002/cphc.201000210.
Determination of DNA hybridization at electrode surfaces modified with thiol-tethered single-stranded DNA (ssDNA) capture probes and co-assembled with short-chain thiol derivatives using electrochemical impedance spectroscopy requires a careful design of the electrode/electrolyte interface as well as an in-depth understanding of the processes at the interface during DNA hybridization. The influence of the electrode potential, the ssDNA coverage, the ionic strength, the nature of the thiol derivative and especially the Debye length are shown to have a significant impact on the impedance spectra. A mixed monolayer comprising--in addition to the ssDNA capture probe--both mercaptohexanol (MCH) and mercaptopropionic acid (MPA) is suggested as an interface design which allows a high efficiency of the DNA hybridization concomitantly with a reliable modulation of the charge-transfer resistance of the electrode upon hybridization.
采用电化学阻抗谱法测定通过硫醇键固定在电极表面的单链 DNA（ssDNA）捕获探针以及与短链硫醇衍生物共组装的 DNA 杂交在电极/电解质界面的精心设计以及对杂交过程中界面过程的深入了解是必要的。电极电势、ssDNA 覆盖率、离子强度、硫醇衍生物的性质以及特别是德拜长度对阻抗谱有显著影响。建议采用混合单层作为界面设计，其中除了 ssDNA 捕获探针外，还包括巯基己醇（MCH）和巯基丙酸（MPA），这可以实现 DNA 杂交的高效率，同时在杂交时可靠地调节电极的电荷转移电阻。
