This velocity is measured using the laser Doppler technique, where the frequency shift or phase shift of an incident laser beam, caused by the moving particles, is measured as the particle mobility.Įxperimentally, protein mobility measurements present two practical challenges. An electrical field is applied and particles or molecules that have a net charge, or more strictly a net zeta potential, will migrate towards the oppositely charged electrode with a velocity, known as the electrophoretic mobility, that is related to their zeta potential.
A sample is introduced into a cell containing two electrodes. The fundamental physical principle in ELS is that of electrophoresis. Recent advances in instrumentation and methodologies are addressing the technical challenges of using light scattering to make mobility measurements on proteins. In the case of proteins, the measurement of protein mobility allows the calculation of protein charge, which in turn relates to factors such as activity and reaction kinetics. This mobility is often converted into zeta potential to enable comparison of materials under different conditions.
Electrophoretic light scattering (ELS) is used to measure the electrophoretic mobility of particles in dispersion or molecules (such as proteins) in solution. Dynamic light scattering (DLS) is established in the measurement of particle and molecular size, and in studying the interactions between proteins. Light scattering techniques are widely used in protein characterization. This article describes an approach to using electrophoretic light scattering to make protein mobility measurements. Protein mobility is one property that has been identified as a promising indicator of formulation stability, viscosity, and behavior. As the number of biopharmaceutical formulations that use proteins as drug molecules continues to increase, the spotlight is being directed on the analytical methods used in their development, formulation, and quality control.
0 kommentar(er)
