Effect of Protein Incorporation on the Nanostructure of the Bicontinuous Microemulsion Phase of Winsor-III Systems: A Small-Angle Neutron Scattering Study

Journal Article · Tue Jan 20 00:00:00 EST 2015 · Langmuir

DOI:https://doi.org/10.1021/la504606x· OSTI ID:1261415

Hayes, Douglas G. ^[1]; Gomez del Rio, Javier A. ^[1]; Ye, Ran ^[1]; Urban, Volker S. ^[2]; Pingali, Sai Venkatesh ^[2]; O’Neill, Hugh M. ^[2]

---

1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Biosystems Engineering and Soil Science
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biology & Soft Matter Division

Small-angle neutron scattering (SANS) analysis using the Teubner₋Strey model has been employed to evaluate the effect of protein incorporation into the middle, bicontinuous microemulsion (BμE) phase of Winsor-III (W_III) systems formed by an aerosol-OT (AOT)/alkyl ethoxylate mixed surfactant system to understand better the extraction of proteins into and out of BμEs and to study the effect of proteins on a system that serves as a biomimetic analog of cell membranes. Under conditions of high salinity, the incorporation of positively charged proteins cytochrome c, lysozyme, and α-chymotrypsin, near their solubilization limit in the BμEs promoted the release of water and oil from the BμEs, a decrease in the quasi-periodic repeat distance (d), an increase in ordering (a decrease in the amphiphilicity factor, f_a) for the surfactant monolayers, and a decrease in the surface area per surfactant headgroup, suggesting that the proteins affected the self-assembly of components in the BμE phase and produced Debye shielding of AOTs sulfonate headgroup. For W_III systems possessing lower salinity, cytochrome c reduced the efficiency of surfactant in the BμE phase, noted by increases in d and f_a, suggesting that the enzyme and AOT underwent ion pairing. We find that the results of this study demonstrate the importance of ionic strength to modulate proteinsurfactant interactions, which in turn will control the release of proteins encapsulated in the BμEs, relevant to W_III-based protein extraction and controlled release from BμE delivery systems, and demonstrate the utility of BμEs as a model system to understand the effect of proteins on biomembranes.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Structural Molecular Biology (CSMB)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER); U.S. Department of Commerce (NIST)
• Grant/Contract Number: AC05-00OR22725; BES-0437507; DMR-9986442.
• OSTI ID: 1261415
• Journal Information: Langmuir, Vol. 31, Issue 6; ISSN 0743-7463
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY