title: Nanoparticle growth and surface chemistry changes in cell-conditioned culture medium.
abstract: When biomolecules attach to engineered nanoparticle (ENP) surfaces, they confer the particles with a new biological identity. Physical format may also radically alter, changing ENP stability and agglomeration state within seconds. In order to measure which biomolecules are associated with early ENP growth, we studied ENPs in conditioned medium from A549 cell culture, using dynamic light scattering (DLS) and linear trap quadrupole electron transfer dissociation mass spectrometry. Two types of 100 nm polystyrene particles (one uncoated and one with an amine functionalized surface) were used to measure the influence of surface type. In identically prepared conditioned medium, agglomeration was visible in all samples after 1 h, but was variable, indicating inter-sample variability in secretion rates and extracellular medium conditions. In samples conditioned for 1 h or more, ENP agglomeration rates varied significantly. Agglomerate size measured by DLS was well correlated with surface sequestered peptide number for uncoated but not for amine coated polystyrene ENPs. Amine-coated ENPs grew much faster and into larger agglomerates associated with fewer sequestered peptides, but including significant sequestered lactose dehydrogenase. We conclude that interference with extracellular peptide balance and oxidoreductase activity via sequestration is worthy of further study, as increased oxidative stress via this new mechanism may be important for cell toxicity.
authors.affiliation: School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT, UK Child Health, Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK michaela_kendall@yahoo.co.uk.
authors.forename: Michaela
authors.initials: M
authors.lastname: Kendall
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Nikolas J
authors.initials: NJ
authors.lastname: Hodges
authors.affiliation: Child Health, Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK.
authors.forename: Harry
authors.initials: H
authors.lastname: Whitwell
authors.affiliation: European Centre of Environment and Human Health, University of Exeter Medical School, Truro, Cornwall, UK.
authors.forename: Jess
authors.initials: J
authors.lastname: Tyrrell
authors.affiliation: Centre for Rare Diseases and Personalised Medicine, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Hakan
authors.initials: H
authors.lastname: Cangul
mesh_terms: D045744:Cell Line, Tumor; D017077:Culture Media, Conditioned / Q000737:chemistry*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D011137:Polystyrenes; D011485:Protein Binding
chemical_list: D017077:Culture Media, Conditioned; D010455:Peptides; D011137:Polystyrenes
keywords: LDH; agglomerate; corona; nanoparticles; peptides; surface