title: A centrifugation-based physicochemical characterization method for the interaction between proteins and nanoparticles.
abstract: Nanomedicine requires in-depth knowledge of nanoparticle-protein interactions. These interactions are studied with methods limited to large or fluorescently labelled nanoparticles as they rely on scattering or fluorescence-correlation signals. Here, we have developed a method based on analytical ultracentrifugation (AUC) as an absorbance-based, label-free tool to determine dissociation constants (KD), stoichiometry (Nmax), and Hill coefficient (n), for the association of bovine serum albumin (BSA) with gold nanoparticles. Absorption at 520 nm in AUC renders the measurements insensitive to unbound and aggregated proteins. Measurements remain accurate and do not become more challenging for small (sub-10 nm) nanoparticles. In AUC, frictional ratio analysis allows for the qualitative assessment of the shape of the analyte. Data suggests that small-nanoparticles/protein complexes significantly deviate from a spherical shape even at maximum coverage. We believe that this method could become one of the established approaches for the characterization of the interaction of (small) nanoparticles with proteins.
authors.affiliation: Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Bekdemir
authors.affiliation: Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.|Interfaculty Institute of Bioengineering, EPFL, CH-1015 Lausanne, Switzerland.
authors.forename: Francesco
authors.identifier: 0000-0003-4635-6080
authors.initials: F
authors.lastname: Stellacci
mesh_terms: D006046:Gold / Q000737:chemistry* / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry*; D008956:Models, Chemical; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D014461:Ultracentrifugation / Q000379:methods*
chemical_list: D012710:Serum Albumin, Bovine; D006046:Gold