The qNano uses the Tunable Resistive Pulse Sensing (TRPS) technique for the “particle by particle” analysis. The TRPS technique is based on measuring changes in the current flowing through the nanopore. Changes, referred to as resistive pulses, are due to the passage of particles (suspended in the electrolyte) through a given nanopore of an adjustable, defined size. By calibrating to a characterized polystyrene standard, this non-optical technique can be used to determine the size and the number of particles in volume. A wide range of the nanopore polyurethane membranes is available to cover the different analyte sizes from 40 nm to 1 μm, depending on the nature of the sample. The measurable sample concentration ranges from 1∙10⁵ to 1∙10¹¹ particles/ml.