A recording of a recent Malvern Instruments web seminar addressing the question of "What is the real sensitivity of DLS [dynamic light scattering] for nanoparticle and protein measurements?" is now freely available on line.
In the seminar, biophysical characterization specialist Dr Ulf Nobbmann explores the limits of each system in the Malvern Zetasizer Nano range and examines best practice methodologies for measuring nanoparticle and protein samples at the extreme ends of the particle size scale. Go to http://www.malvern.com/realsensitivity
Malvern's Zetasizer Nano systems use light scattering techniques to measure the hydrodynamic size, zeta potential and molecular weight of proteins and nanoparticles. Particles scatter light with an intensity proportional to size to the 6th power. This means that very small objects scatter very little light, eventually limiting the size or concentration measureable, while large particles may sediment and affect the result. Too few particles in the scattering volume will cause undesirable intensity fluctuations.
It is therefore necessary to ensure that the limits for reliable measurements for each sample type are fully understood. Once understood, it is often possible to change measurement procedures to extend the potential range of applications suitable for the technique.