Particle Concentration and Size using the Spectradyne nCS1

This protocol describes the use of the Spectradyne nCS1 instrument to measure the particles per mL concentration and size of nanoparticles. The Spectradyne nCS1 is a particle analyzing instrument that uses microfluidic resistive pulse sensing rather than optical measurements to determine the concentration and size of samples. Microliters (typically 5 μL) of a sample are placed in a microfluidic cartridge that is inserted into the instrument for analysis; thus, low sample volumes are needed for analysis and the instrument is relatively easy to use. The size and concentration of a sample is determined by measuring the changes in voltage as particles travel through a nano-constriction in the microfluidic cartridge. This method also has the advantage over optical techniques in that measurements are not dependent on the type of material being measured ( e.g., refractive index of the sample itself is not needed for accurate analysis).