title: Model system to study the influence of aggregation on the hemolytic potential of silica nanoparticles.
abstract: A well-defined silica nanoparticle model system was developed to study the effect of the size and structure of aggregates on their membranolytic activity. The aggregates were stable and characterized using transmission electron microscopy, dynamic light scattering, nitrogen adsorption, small-angle X-ray scattering, infrared spectroscopy, and electron paramagnetic resonance. Human red blood cells were used for assessing the membranolytic activity of aggregates. We found a decreasing hemolytic activity for increasing hydrodynamic diameter of the nanoparticle aggregates, in contrast to trends observed for isolated particles. We propose here a qualitative model that considers the fractal structure of the aggregates and its influence on membrane deformation to explain these observations. The open structure of the aggregates means that only a limited number of primary particles, from which the aggregates are built up, are in contact with the cell membrane. The adhesion energy is thus expected to decrease resulting in an overall lowered driving force for membrane deformation. Hence, the hemolytic activity of aggregates, following an excessive deformation of the cell membrane, decreases as the aggregate size increases. Our results indicate that the aggregate size and structure determine the hemolytic activity of silica nanoparticle aggregates.
authors.affiliation: Center for Surface Chemistry & Catalysis, Katholieke Universiteit Leuven, Heverlee, Belgium.
authors.forename: Leen C J
authors.initials: LC
authors.lastname: Thomassen
authors.forename: Virginie
authors.initials: V
authors.lastname: Rabolli
authors.forename: Kasper
authors.initials: K
authors.lastname: Masschaele
authors.forename: Gabriele
authors.initials: G
authors.lastname: Alberto
authors.forename: Maura
authors.initials: M
authors.lastname: Tomatis
authors.forename: Mara
authors.initials: M
authors.lastname: Ghiazza
authors.forename: Francesco
authors.initials: F
authors.lastname: Turci
authors.forename: Eric
authors.initials: E
authors.lastname: Breynaert
authors.forename: Gianmario
authors.initials: G
authors.lastname: Martra
authors.forename: Christine E A
authors.initials: CE
authors.lastname: Kirschhock
authors.forename: Johan A
authors.initials: JA
authors.lastname: Martens
authors.forename: Dominique
authors.initials: D
authors.lastname: Lison
authors.forename: Bice
authors.initials: B
authors.lastname: Fubini
mesh_terms: D000327:Adsorption; D002448:Cell Adhesion; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D004907:Erythrocyte Deformability / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D006461:Hemolysis / Q000187:drug effects*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008954:Models, Biological; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D012822:Silicon Dioxide