Spectradyne's nCS1 instrument and associated analysis cartridges,shown to the right, are based on Spectradyne's patented nanoparticle analyzer (NPA) technology. The heart of the instrument is the microfluidic cartridge, which allows the electrical detection of nanoparticles as they pass one by one through a nanoconstriction. Particles larger than the nanoconstriction are removed before reaching it by filters that are built into the cartridge. No pre-filtering of the sample is required by the user.
A single nanoparticle increases the electrical resistance of the suspending fluid as it passes through the nanoconstriction, giving rise to a brief voltage pulse. The size of the pulse is proportional to the nanoparticle volume; the amplitude and duration of the pulse gives the particle diameter and the mean velocity, a method known as resistive pulse sensing. Longer measurements accumulate many pulses.
Software-based analysis is used to combine measurements of a large number of particles into a histogram of particle diameters, with the vertical scale in units of nanoparticle concentration. After removing the dependence on the width of histogram binning, the resulting Concentration Spectral Density (CSD) has units of nanoparticles per unit volume per unit diameter (e.g., particles · mL-1 · nm-1). Because of the fast measurement capability of the nCS1, good statistics can be obtained in a few seconds.
The nCS1 is based on patented technology licensed from the University of California at Santa Barbara, invented by two of Spectradyne's founders. A more technical description of the measurement platform may be found in Nature Nanotechnology in 2011.