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Sizing & Polydispersity

Sizing & polydispersity

Use DLS to measure size and see aggregation

Dynamic light scattering

Dynamic light scattering (DLS) is a highly sensitive technique to check the expected size and polydispersity of proteins or other macromolecules in solution. The polydispersity index (PDI) indicates the level of heterogeneity of particle diameters in the sample. Non-uniform particle sizes in solution give a high PDI, while uniform particle sizes yield a low PDI. When samples get stressed out by the wrong formulation, storage conditions, or a thermal ramp you can watch size and PDI increase as your sample has issues. DLS helps uncover the presence of aggregates or contaminants in your sample that would be missed by UV/Vis detection or other quantification methods alone.

Uncle

Uncle is the one-stop stability platform for biologics. Not only do you get DLS for cranking out sizing, polydispersity and aggregation data, Uncle also has fluorescence and SLS for checking out thermal melting, thermal aggregation, B22, and a whole lot more on your biologic. All the info you’ll get makes picking the best formulation, protein, or viral vector a piece of cake.

Stunner

Stunner pulls rank on other systems because it’s way, way more than just DLS. It lets you get a grip on what storage, agitation or a change to your process or formulation does to your protein. See if there’s any aggregation, measure the hydrodynamic size, grab polydispersity when you need to check uniformity, and get the exact concentration while you’re at it.

UV/Vis and DLS also combine to uniquely measure colloidal stability of your samples with kD or B22 data. Instead of making assumptions, Stunner takes an accurate read on concentration for every data point and combines that with DLS data to show how your protein is interacting with itself in solution.

Punk

If DLS is all you need then Punk is your go-to. All it takes is a quick check on 5 µL of sample to see if you’ve got stuff you don’t want — like protein aggregation. The Punk whips out info on sample size distribution and if your protein’s started to aggregate or not in about 30 seconds.