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. Aminecoated 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.

Toxicity evaluations of nanoclays and thermally degraded byproducts through spectroscopical and microscopical approaches

“…Agglomerate’s size distribution was a function of the sample’s chemical signature (Fig. 3), with cell culture media with 5% serum containing appropriate cell growth proteins favoring larger agglomerates formation than PBS alone, likely due to the interactions of the clays with the proteins in the media forming coronas [59,60]. Interestingly, analyses showed that CC displayed smaller diameter sizes in both media and PBS relative to the other three samples, likely due to the presence of the organic modifier (Fig.…”

Antibacterial Metal Oxide Nanoparticles: Challenges in Interpreting the Literature

“…These media constituents can greatly affect the surface chemistry of MO-NPs by changing zeta potential, dissolving the particle, or blocking interactions. Media contents can make NPs unstable through ion/molecule/protein adsorption or loss of surface functionality, resulting in the formation of aggregates(36, 62). The role of complex NP corona ( i.e.…”

Poly(D,L-Lactic Acid) Nanoparticle Size Reduction Increases Its Immunotoxicity

“…This knowledge gap partially results from the fact that NPs physicochemical properties, particularly its reduced size, hinder the application of traditional toxicity assays and further contribute to the misinterpretation of results and ambiguous conclusions among research groups (Dobrovolskaia et al, 2009). Additionally, the mandatory use of biological medium during toxicological assays can modify the NPs characteristics such as size, surface charge and morphology, through phenomenon's like protein corona formation and particle agglomeration, which will therefore influence the immunotoxicity profile of the NPs (Kendall et al, 2014). Therefore, a detailed characterization of the NPs in the experimental assay conditions is crucial to discuss the results, but is commonly absent from the scientific published reports.…”