Merkel Technologies offers uniques solutions for nanoparticle analysis:

The Particle Metrix solutions for particle size, concentration and charge measurement, by Nanoparticle Tracking Analysis of Dynamic Light Scattering.

Particle Metrix

The A50-Micro from Apogee Flow Systems, for flow cytometry analysis of nanoparticles, that is  in a class of its own for sub-micron biological particles, and leading the field in extracellular vesicle research, amongst others.