AF4 experiments at CoSAXS

What is AF4 and why use it on the CoSAXS beamline?  
The purpose of the beam time was to investigate if asymmetric flow field-flow fractionation (AF4) could be connected online to SAXS. AF4 is a sized-based chromatography-like separation technique which does not utilize a packed column. This allows separation in a very wide size-range under low shear force and low internal surface area. The intention was to demonstrate the feasibility of this set-up using different samples. The experiments included separation and characterization of proteins, protein aggregates/supra-molecular assemblies, lipid nanoparticles, mixtures of blood serum and magnetic nanoparticles and polysaccharides.   

What is the benefit of connecting these techniques together? 
The ability to online size-separate samples prior to SAXS measurements (especially when size-exclusion chromatography is unsuitable) would give new and exciting possibilities for characterization of, for instance, multispecies samples of proteins and nanoparticles.  

What was the outcome of the beamtime?  
In general, it was successful, and we will be able to show the intended feasibility i.e. we can connect AF4 online and obtain SAXS data over the size-distribution. We obtained a large amount of data which we are now starting to process in detail.  

The road-ahead 
The next step will be to start utilizing this setup for “real” relevant research questions. In this regard we also welcome comments, suggestions and collaboration form the participants in NextBioForm. 

To get in touch with Lars or Hans, please e-mail: 

lars.nilsson@food.lth.se 

hans.bolinsson@food.lth.se