Characterization of Recombinant Therapeutic Protein Adsorption in the Presence of Selected Surfactant Species at the Air-Water Interface

The primary goal of this project was to characterize the protein adsorption of a recombinant therapeutic protein at liquid-air interfaces and suggest possible process improvements to reduce adsorption. A dynamic interfacial tensiometer was used to measure the surface tension of aqueous solutions of protein. Initially, fibrinogen was used as a model protein. After developing the appropriate experimental processes using this model protein, the therapeutic protein was used in further experiments. After establishing baseline adsorption values for protein only, two surfactants were investigated in order to help reduce the undesired adsorption during commercial protein production: Tween 80 and PluronicTM F68. Within dilute protein conditions, it was found that surfactant behavior depended heavily on surfactant concentration. While F68 proved to be a faster-acting surfactant and more efficient at reducing protein adsorption at low surfactant concentrations, Tween 80 proved to be superior in the higher surfactant concentration ranges and under conditions typical in the processing of the therapeutic protein. Conclusions point to the possibility of significantly decreasing upstream protein losses via the use of Tween 80 in the protein production process. Thus, it is recommended that further investigation of Tween 80 be conducted using a bench or pilot-scale process which more closely mimics commercial scale production vessels.