Introduction
Dynamic light scattering (DLS) is commonly used in particle size analysis as an indicator of solution homogeneity or aggregate formation.
This technology can be used to find the best conditions for protein crystallization.
Particle size from 1 nm to 1 µm is determined by measuring random variations in the intensity of light scattered by a suspension or emulsion.
www.wyatt.com/solutions/techniques/dynamic-light-scattering-nanoparticle-size.html
Principle
Small particles in suspension are subjected to a random thermal motion called Brownian motion. This motion is correlated to 1) the hydrodynamic diameter of the particles, which corresponds to the size of a sphere that would scatter light in the same way, and 2) the transverse scattering coefficient which is measured by dynamic light scattering. Viscosity and temperature also come into play.
The light from the laser light source illuminates the sample, and the scattered light signal is collected by a detector at an angle of 158°C. The resulting optical signal shows random variations that result from the movement of the particles.
This signal is processed in real time by a device called an autocorrelator, and allows to obtain an autocorrelation function that simulates the loss of correlation of the signal as a function of time.
From this autocorrelation function can be deduced the size of the particles: if the particle is large, the signal changes slowly and the correlation persists for a long time. Otherwise, small particles move quickly and the correlation is lost more quickly.
Protocol
| Format | 384 wells | ||
| Detection | Dynapro Plate Reader® Wyatt Technology 10 acquisitions / well 5 seconds / acquisition | ||
Determination of BSA size by dynamic light scattering measurement
Volume : 60 µL
Concentrations : 0,015 to 2 mg/mL
