title: Emergent membrane-affecting properties of BSA-gold nanoparticle constructs.
abstract: By adsorbing bovine serum albumin (BSA) on gold nanoparticles (Aunps) with diameters 30 nm and 80 nm, different degrees of protein unfolding were obtained. Adsorption and adlayer conformation were characterized by UV-vis spectroscopy, ζ-potential measurements, steady-state and time-resolved fluorescence. The unfolding was also studied using 1-anilino-8-naphthalene sulfonate (ANS) as an extrinsic probe, showing that BSA unfolds more on 80 nm Aunp than on 30 nm Aunp. Langmuir monolayer studies using two distinct methods of introducing the BSA and BSA-Aunp constructs accompanied with Brewster Angle Microscopy (BAM) and Digital Video Microscope (DVM) imaging demonstrated that BSA-Aunp constructs induce film miscibility with L-α-phosphatidylethanolamine not seen for BSA or Aunp alone. The changes induced by partial unfolding clearly give better film-penetration ability, as well as disruption of liquid crystalline domains in the film, thereby inducing film miscibility. Gold or protein only does not possess the nanoscale film-affecting properties of the protein-gold constructs, and as such the surface-active and miscibility-affecting characteristics of the BSA-Aunp represent emergent qualities.
authors.affiliation: Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), N-7491, Trondheim, Norway. lystvet@chemeng.ntnu.no
authors.forename: Sina M
authors.initials: SM
authors.lastname: Lystvet
authors.forename: Sondre
authors.initials: S
authors.lastname: Volden
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yasuda
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Halskau
authors.forename: Wilhelm R
authors.initials: WR
authors.lastname: Glomm
mesh_terms: D006046:Gold / Q000737:chemistry*; D008422:Materials Testing; D008567:Membranes, Artificial; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011487:Protein Conformation; D017510:Protein Folding; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D008567:Membranes, Artificial; D012710:Serum Albumin, Bovine; D006046:Gold