title: Liquid Surface X-ray Studies of Gold Nanoparticle-Phospholipid Films at the Air/Water Interface.
abstract: Amphiphilic phospholipids and nanoparticles functionalized with hydrophobic capping ligands have been extensively investigated for their capacity to self-assemble into Langmuir monolayers at the air/water interface. However, understanding of composite films consisting of both nanoparticles and phospholipids, and by extension, the complex interactions arising between nanomaterials and biological membranes, remains limited. In this work, dodecanethiol-capped gold nanoparticles (Au-NPs) with an average core diameter of 6 nm were incorporated into 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers with surface densities ranging from 0.1 to 20% area coverage at a surface pressure of 30 mN/m. High resolution liquid surface X-ray scattering studies revealed a phase separation of the DPPC and Au-NP components of the composite film, as confirmed with atomic force microscopy after the film was transferred to a substrate. At low Au-NP content, the structural organization of the phase-separated film is best described as a DPPC film containing isolated islands of Au-NPs. However, increasing the Au-NP content beyond 5% area coverage transforms the structural organization of the composite film to a long-range interconnected network of Au-NP strands surrounding small seas of DPPC, where the density of the Au-NP network increases with increasing Au-NP content. The observed phase separation and structural organization of the phospholipid and nanoparticle components in these Langmuir monolayers are useful for understanding interactions of nanoparticles with biological membranes.
authors.affiliation: James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Siheng Sean
authors.initials: SS
authors.lastname: You
authors.affiliation: James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.|Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Charles T R
authors.initials: CT
authors.lastname: Heffern
authors.affiliation: Department of Physics, The University of California-San Diego , La Jolla, California 92093, United States.
authors.forename: Yeling
authors.initials: Y
authors.lastname: Dai
authors.affiliation: Center for Advanced Radiation Sources, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Mati
authors.initials: M
authors.lastname: Meron
authors.affiliation: James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.|Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: J Michael
authors.initials: JM
authors.lastname: Henderson
authors.affiliation: Center for Advanced Radiation Sources, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Bu
authors.affiliation: James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.|Department of Chemical Engineering, City College of New York , New York City, New York 10031, United States.
authors.forename: Wenyi
authors.initials: W
authors.lastname: Xie
authors.affiliation: James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.|Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States.|Institute for Biophysical Dynamics, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Ka Yee C
authors.initials: KY
authors.lastname: Lee
authors.affiliation: James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.|Center for Advanced Radiation Sources, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Binhua
authors.initials: B
authors.lastname: Lin