title: Protein-silicone oil interactions: comparative effect of nonionic surfactants on the interfacial behavior of a fusion protein.
abstract: OBJECTIVE
  To study the effect of three nonionic surfactants on the protein-silicone oil interactions.
  
  
  METHODS
  The adsorption of Tween® 80, Pluronic® F68 and Tween® 20 at the silicone oil/water interface (using shifts in frequency (ΔF) and resistance (ΔR) with quartz crystal microbalance) was compared to the adsorption at air/water interface (using surface tension). Effect of surfactants on protein adsorption to the silicone oil/water interface was studied in sequential- and co-adsorption modes. Protein-surfactant binding in the bulk was measured using dynamic surface tension method.
  
  
  RESULTS
  Saturation of air/water and silicone oil/water interfaces by surfactants was observed at similar bulk concentrations. ΔF due to protein adsorption to the interface decreased only when surfactant was present as a pre-adsorbed species. Insignificant differences in the dynamic surface tension values of surfactant solutions were observed in the presence of protein.
  
  
  CONCLUSIONS
  Similar hydrophobic forces were responsible for driving the surfactant adsorption at both air/water and silicone oil/water interfaces. Surfactants were effective in reducing the protein adsorption to the silicone oil only when introduced before or along with the protein. No significant binding between the protein and surfactants was observed in the bulk.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, 69 N Eagleville Road, Unit 3092, Storrs, Connecticut 06269, USA.
authors.forename: Nitin
authors.initials: N
authors.lastname: Dixit
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Maloney
authors.forename: Devendra S
authors.initials: DS
authors.lastname: Kalonia
mesh_terms: D000327:Adsorption; D004548:Elasticity; D020442:Poloxamer / Q000737:chemistry*; D011136:Polysorbates / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000737:chemistry*; D012827:Silicone Oils / Q000737:chemistry*; D013499:Surface Properties; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*; D014783:Viscosity
chemical_list: D011136:Polysorbates; D011993:Recombinant Fusion Proteins; D012827:Silicone Oils; D013501:Surface-Active Agents; D020442:Poloxamer