Abstract: Systems and techniques for probing interfaces between electrodes and conductive solutions. In one aspect, devices can include a time variable source of power configured to output power that varies in time over a pair of output conductors, an electrode connected to a first of the conductors, an extrinsic inductive impedance connected between the pair of output conductors, and an impedance sensor connected to one or both of the output conductors and configured to measure net impedance between the pair of output conductors based on a known current or voltage output by the time variable power output. The measured net impedance includes the extrinsic inductive impedance and an impedance of the interface. The electrode is configured to be submersed in a conducting solution and form an interface with the conducting solution.

Abstract: A single electron transistor device for sensing at least one particle, includes at least two electrodes positioned with a gap formed between the electrodes and an activation object positioned in the gap with an insulating layer between the activation object and each electrode. The activation object which is able to transfer electrons is arranged with at least one binding structure bonded to it for receiving the at least one particle. The electrodes are formed with an inter distance of less than 50 nm and the electrodes are connectable directly or indirectly to a signal acquisition system. The sensing device is arranged to allow a tunnelling current proportional to the presence of the at least one particle in the binding structure, to flow through the activation object. A method, and system using a single electron transistor device fabricated with micro/nano fabrication methods are also disclosed.