This technology consists in applying an electric field to the charged nanoparticles (NPs). Due to their electrostatic charge, NPs are moving.
Launching a laser into those NPs, we can measure their speed using the Laser Doppler Electrophoresis (LDE) technique. Measuring their speed, we can then determine their mobility.
Zeta potential is directly linked to the mobility of NPs according to various theories (Smoluchovski or Huckel).