Recombinant factor VIII protein aggregation and adsorption at the liquid-solid interface

Undesired aggregation and adsorption of therapeutic proteins during manufacturing and administration processes can significantly decrease the efficacy of protein drugs, especially when a quantitative treatment is critical. In this study, we investigate molecular interactions of recombinant factor VIII (rFVIII), a therapeutic protein for hemophilia A treatment, at a static liquid-glass interface. We quantitatively analyze the adsorption and aggregation of rFVIII using atomic force microscopy (AFM), dynamic light scattering (DLS) and UV-Vis spectroscopy. We also investigate how PEGylation, temperature, ionic strength and pH affect the rFVIII aggregation and adsorption at the interface over time. The aggregation and adsorption of rFVIII are significantly reduced by decreasing electrostatic attractions in the solution. We observed that the PEGylation endows rFVIII molecules with high stability at the liquid-glass interface in a wide range of temperature, ionic strength and pH. Our studies will help to understand the molecular interactions of how proteins aggregate and adsorb on the solid surface and prevent the undesired events in pharmaceutical applications.