RESUMO
Nanomaterial (NM) surface chemistry has an established and significant effect on interactions at the nano-bio interface, with important toxicological consequences for manufactured NMs, as well as potent effects on the pharmacokinetics and efficacy of nano-therapies. In this work, the effects of different surface modifications (PVP, Dispex AA4040, and Pluronic F127) on the uptake, cellular distribution, and degradation of titanium dioxide NMs (TiO2 NMs, ~10 nm core size) are assessed and correlated with the localization of fluorescently-labeled serum proteins forming their coronas. Imaging approaches with an increasing spatial resolution, including automated high throughput live cell imaging, correlative confocal fluorescence and reflectance microscopy, and dSTORM super-resolution microscopy, are used to explore the cellular fate of these NMs and their associated serum proteins. Uncoated TiO2 NMs demonstrate a rapid loss of corona proteins, while surface coating results in the retention of the corona signal after internalization for at least 24 h (varying with coating composition). Imaging with two-color super-resolution dSTORM revealed that the apparent TiO2 NM single agglomerates observed in diffraction-limited confocal microscopy are actually adjacent smaller agglomerates, and provides novel insights into the spatial arrangement of the initial and exchanged coronas adsorbed at the NM surfaces.
RESUMO
Manufactured nanomaterials (MNMs) selected from a library of over 120 different MNMs with varied compositions, sizes, and surface coatings were tested by four different laboratories for toxicity by high-throughput/-content (HT/C) techniques. The selected particles comprise 14 MNMs composed of CeO2, Ag, TiO2, ZnO and SiO2 with different coatings and surface characteristics at varying concentrations. The MNMs were tested in different mammalian cell lines at concentrations between 0.5 and 250 µg/mL to link physical-chemical properties to multiple adverse effects. The cell lines are derived from relevant organs such as liver, lung, colon and the immune system. Endpoints such as viable cell count, cell membrane permeability, apoptotic cell death, mitochondrial membrane potential, lysosomal acidification and steatosis have been studied. Soluble MNMs, Ag and ZnO, were toxic in all cell types. TiO2 and SiO2 MNMs also triggered toxicity in some, but not all, cell types and the cell type-specific effects were influenced by the specific coating and surface modification. CeO2 MNMs were nearly ineffective in our test systems. Differentiated liver cells appear to be most sensitive to MNMs, Whereas most of the investigated MNMs showed no acute toxicity, it became clear that some show adverse effects dependent on the assay and cell line. Hence, it is advised that future nanosafety studies utilise a multi-parametric approach such as HT/C screening to avoid missing signs of toxicity. Furthermore, some of the cell type-specific effects should be followed up in more detail and might also provide an incentive to address potential adverse effects in vivo in the relevant organ.