A typical use of dynamic light scattering (DLS) at SOLVE is particle size analysis and screening of protein solutions for aggregates. We have the traditional DLS cuvette format, but also a DLS plate reader for high-throughput analysis and screenings, that utilizes low sample volumes. Our instrumentation is temperature controlled which is handy for stability investigations. We use DLS instrumentation from Wyatt Technology and Malvern.
Principle:
Dynamic light scattering (DLS), also referred to as quasi-elastic light scattering (QELS) or photon correlation spectroscopy (PCS), is a spectroscopic technique that measures the Brownian motion of particles/macromolecules in solution. The measured Brownian motion is related to the diffusion coefficient and from that the hydrodynamic size (Stokes radius) can be obtained.
Applicability:
Dynamic light scattering (DLS) is applicable to particles and macromolecules from ~ 1 nm to ~1 µm. It can thereby be applied to everything from antibody, peptides and proteins, to nanoparticles and viruses. Typical applications of DLS are particle size analysis, screening of buffer conditions during formulation, stability testing, and aggregation analysis.
Pros
- No (or minimum) method development
- Fast (high-throughput)
- Native conditions (concentration and solvent)
- Low sample volume (down to ~30µl)
- Experimentally relatively straight-forward
- Low surface area and no shear
Cons
- Limited resolution
- Semi-quantitative
- Difficult to evaluate for polydisperse samples
- Not suited for complex matrices
- Molar mass and Mw info through assumptions
- Sensitive to particulate impurities