Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark.
Biosens Bioelectron. 2013 Dec 15;50:269-77. doi: 10.1016/j.bios.2013.06.059. Epub 2013 Jul 4.
Current-time and steady state current behaviour was simulated for the cases of a hemispherical and flat inlaid disk electrodes located under a hemispherical polymer drop containing an enzyme which converts a substrate diffusing into the drop into a product that is electroactive at the electrode. As well, a cylindrical electrode with length much greater than its diameter and coated with a layer of polymer/enzyme was treated. The ratio of steady state currents at the hemispherical to the disk electrode is not, as has sometimes been assumed, always equal to π/2; indeed this is only approached for polymer drops with large spillover ratio, that is, having a radius much larger than that of the electrodes. Steady state currents for all electrode geometries (including the cylinder) go through a maximum for some spillover ratio and then approach a constant value for larger spillover ratios. This constant value is the same as that for the diffusion limited current in a semi-infinite medium. For a cylindrical electrode, the steady state current tends towards zero for large spillover ratios.
对位于半球形聚合物液滴下方的半球形和平面嵌入式盘电极的情况进行了暂态和稳态电流行为的模拟，该聚合物液滴中含有一种酶，可将扩散进入液滴的底物转化为在电极处具有电化学活性的产物。此外，还对长度远大于其直径且涂有聚合物/酶层的圆柱形电极进行了处理。如有时假设的那样，半球形电极和盘电极之间的稳态电流比并不总是等于π/2；实际上，对于具有大溢出比（即半径远大于电极半径）的聚合物液滴，才接近此值。对于所有电极几何形状（包括圆柱体），在某些溢出比下，稳态电流会通过最大值，然后对于较大的溢出比趋近于恒定值。此恒定值与半无限介质中扩散限制电流的值相同。对于圆柱形电极，对于较大的溢出比，稳态电流趋于零。
