Hybrid system for complex AC sensing of nanowires

A compact and low cost hybrid system enabling AC real-time measurements, as well as impedance characterization of bio-nanosensors is presented. The instrument has been tailored for nanowire-based sensors and sensing is measured with performing amperometric techniques with lock-in to measure the complex impedance detection. In addition to the magnitude of the impedance, the system also measures the phase of which provides additional information on the surface-electrolyte interface. The system is user-friendly with a custom software interface so that it can be adapted for different bio-nanosensors and experimental systems. The system was tested by performing real time detection of pH changes and measuring surface chemical modification of of top-down fabricated nanowires. The measurements demonstrate that the phase data provides additional information to the standard measure of conductance.