Nanopores are the core part of a fluidic system filled with an electrolyte solution. When a bias voltage is applied across the pore, an ionic current flows through the nanopore. Any molecule or particle that goes through the pore can be detected as a transient drop in the current readout. Analysis  of the current drop can provide information about the size and shape of the molecule or particle. They are classified into two groups based on their material and fabrication procedure: membrane-embedded pores and solid-state pores.