Photoelectrochemical signal chain based on quantum dots on gold--sensitive to superoxide radicals in solution.
Photoelectrochemical signal chain based on quantum dots on gold--sensitive to superoxide radicals in solution.
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DOI：
10.1016/j.bios.2008.03.039
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发表时间：
2008-10
影响因子：
12.6
通讯作者：
C. Stoll;C. Gehring;Kirsten Schubert;M. Zanella;W. Parak;F. Lisdat
中科院分区：
文献类型：
--
作者：
C. Stoll;C. Gehring;Kirsten Schubert;M. Zanella;W. Parak;F. Lisdat
利用二巯基化合物将CdSe/ZnS量子点固定在金电极上，制备了一种对超氧自由基敏感的光电化学信号链。在照明下的光电流产生的条件的特征在于相对于所施加的电极电位，光束的波长和测量的稳定性的依赖性。由于光激发，在纳米颗粒中强制产生电子-空穴对，从而增强量子点层的导电性。通过阻抗测量独立验证了这一点。为了观察与氧化还原蛋白质细胞色素c的直接电子转移，研究了量子点的不同表面修饰巯基丙酸、巯基琥珀酸和巯基吡啶。溶液中不同的超氧化物浓度可以通过超氧化物还原的细胞色素c的增强转化来检测，从而通过量子点修饰电极处的增强的光电流来检测。发现电极对更高纳摩尔浓度的自由基敏感。
A photoelectrochemical signal chain sensitive to the presence of superoxide radicals was developed on the basis of CdSe/ZnS quantum dots which were immobilized on gold electrodes using a dithiol compound. The conditions of photo current generation under illumination have been characterized with respect to the dependence on the applied electrode potential, the wavelength of the light beam and the stability of the measurement. Because of photoexcitation electron–hole pair generation is enforced in the nanoparticles enhancing the conductivity of the quantum dot layer. This was independently verified by impedance measurements. In order to observe direct electron transfer with the redox protein cytochrome c different surface modifications of the quantum dots were investigated—mercaptopropionic acid, mercaptosuccinic acid and mercaptopyridine. Varying superoxide concentrations in solution can be detected by an enhanced conversion of superoxide-reduced cytochrome c and thus by an enhanced photo current at the quantum dot modified electrode. The electrode was found to be sensitive to higher nanomolar concentrations of the radical.