Near-field ion flow for molecular scale manipulation

By applying electrical pulse wave into highly-ionized solution, we observed that protein can be efficiently transported toward the electrode surface regardless the protein is positive or negative charged. The operational frequency and electrical potential of the driving electrical pulse waves are not in the range of typical electrokinetic. Here we hypothesized a fluidic movement normal to the electrode surface, named near-field ion flow, was driven by the movement of ions when the electrical double layer is being formed. The hypothesis was experimentally supported by showing that more enzyme was transported toward electrode surface after applying pulse. The investigation provides an alternative way to manipulating fluidic movement without complicate microfluidics implementation.