|author||Han Young Woo|
|Homepage||http://Journal of the American Chemical ...s.7b12382)|
Ji-Eun Jeong (박사과정)
Direct electron transfer between a redox label and an electrode requires a very short working distance (<1-2 nm), and in general an affinity biosensor based on the direct electron transfer requires a finely smoothed Au electrode surface to support efficient target binding. Here, we report that direct electron transfer over a longer working distance is possible between (i) an anionic p-conjugated polyelectrolyte (CPE) label having many redox-active sites and (ii) a readily prepared, thin polymeric monolayer-modified indium-tin oxide (ITO) electrode. In addition, the long and flexible CPE label (~18 nm for 10 kDa) can approach the electrode within the working distance after sandwich-type target-specific binding, and fast CPE-mediated oxidation of ammonia-borane along the entire CPE backbone affords high signal amplification. Negatively charged casein and hydrophilic side chains of the CPE minimize nonspecific adsorption of a CPE-labeled DNA onto the ITO electrode. All are beneficial for sensitive washing-free DNA detection.
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