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Voltage is applied across the fluid cell via the silver/silver chloride (Ag/
AgCl) electrodes. When electrolyte ions move between the electrodes
through the nanopore, it creates a baseline current. A temporary decrease
in current is detected as particles pass though the nanopore, which allows
for the sizing and counting of particles in suspension.
Size and concentration measurements
Sample particles are driven through the nanopore by applying a combination
of voltage and pressure (from the variable pressure module, or VPM), and
each particle translocation event causes a resistive pulse or “blockade” signal
that is detected and measured by the application software.
— Blockade magnitude is directly proportional to the particle diameter.
— Blockade frequency is used to determine particle concentration.
Figure 2. Magnitude and frequency measurements are converted into particle size and
concentration by calibrating with particles of known size and concentration.
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