Preservation of the soft protein corona in distinct flow allows identification of weakly bound proteins

Nanocarriers used for targeted drug delivery come into contact with biological liquid and proteins will adsorb to the nanocarriers’ surface forming the so-called ‘protein corona’. The protein corona defines the biological identity and determines the fate of the nanomaterial. To make nanomedicine safe and reliable it is required to identify the composition of the protein corona. Currently, centrifugation is the common method to isolate the protein corona for further investigations. However, with this method it is only possible to investigate the strongly bound proteins, also referred to as ‘hard protein corona’. Therefore, we want to introduce asymmetric flow field-flow fractionation (AF4) as a new technique to isolate nanoparticles including the ‘soft protein corona’ containing also loosely bound proteins for further characterizations. We were able to separate the nanoparticles with a preserved soft protein corona and could show that only the hard protein corona directly influences the cell uptake behavior.