Physicochemical Characteristics of Polymer-Coated Metal-Oxide Nanoparticles and their Toxicological Effects on Zebrafish (Danio rerio) Development

Abstract

Coated nanoparticles (NPs) will end up in the environment due to their proposed use in agricultural applications and may potentially cause toxic effects due to their unique properties. To determine the effects of coated NPs on zebrafish (Danio rerio) development, we tested aqueous poly(acrylic acid) (PAA)-coated metal-oxide NPs including TiO2, ZnO, Fe2O3, and CeO2, as well as the polymer coating alone (nanocapsule). Zebrafish embryos were exposed to NPs over a 72 h period at 1, 10, 50, 100, 200, 400, 800, 1200, 1600, and 2000 mg/L to measure various end points. We also ran free metal controls. Time-dependent changes in physicochemical properties of NPs were characterized using dynamic light scattering. Dissolution experiments over 72 h showed minimal free metals were present in stock suspensions and released from the NPs. Interestingly, nanocapsules (≥ 800 mg/L) cause inhibition of hatch, and we suggest that a low pH environment may explain this effect. This study has also demonstrated that CeO2 NPs and nanocapsules containing Nile red are able to traverse the chorion. Overall, our findings indicate that each NP type is stable and neither the NP or encapsulating PAA coating causes apparent toxicity to developing zebrafish.

Rationally designed porous polystyrene encapsulated zirconium phosphate nanocomposite for highly efficient fluoride uptake in waters

“…the positive-charged quaternary ammonium groups binding to the host materials could present electrostatic interaction towards the target fluoride ions, leading to the enhanced sorption diffusion kinetics and fluoride ions enrichment, prior to sequestration by nano-ZrP, such phenomenon is the so-called “Donnan membrane effect”3839. Recent research also further proved that such polymer encapsulating metal nanoparticles could cause negligible toxic effects on organism in waters40. Besides, the excellent chemical stability and non-toxic properties of ZrP particles also render us believe that the hybrid nanomaterial ZrP-MPN is a promising adsorbent towards fluoride retention.…”

Polymer‐Coated Metal‐Oxide Nanoparticles Inhibit IgE Receptor Binding, Cellular Signaling, and Degranulation in a Mast Cell‐like Cell Line

“…Thus, ZnO may attract more PAA than TiO 2 , for example, and form thicker polymer coats that could mask adverse core material‐mediated effects such as toxicity. The effects on viability were likely not related to the release of core metal ions as the dissolution of PAA‐NPs have not been demonstrated in ultrapure water,10 or in simulated biological solutions 23. As well, viability did not decrease over 24 h when RBL‐2H3 cells were exposed to Ti, Zn, Fe, and Ce ions (data not shown) at dialyzed concentrations previously determined for PAA‐NPs 10…”

“…Given that the primary particle diameters of the PAA‐NPs tested in this study are between 3 and 10 nm10, 22 and have high negative charge,22 we investigated the hypothesis that these smaller materials may still bind FcεRI and sterically obstruct IgE from properly attaching to the receptor and therefore inhibit the degranulatory response. Our data showed that cells pre‐exposed to PAA‐TiO 2 had significant reductions in IgE binding, relative to control, suggesting that PAA‐TiO 2 altered the attachment of IgE to FcεRI.…”

“…All stocks were stored at 4 °C and protected from light. The methods used to synthesize are described by Felix et al10 We had conducted extensive characterization of stock PAA‐NPs as previously reported 6, 10, 22. These included hydrodynamic diameter, polydispersity index, and zeta potential at 0 and 24 h for working stock solutions at concentrations between 10 and 200 μg mL −1 in ddH 2 O, plus transmission electron microscopy (TEM) images for each PAA‐NP.…”

Aquatic toxicity of manufactured nanomaterials: challenges and recommendations for future toxicity testing

“…Nonetheless, dissolution analysis was performed in ultrapure water whereas dissolution will likely be greater at the higher ionic strength of the tap water used in the experiments and also likely in the high ionic strength environment of chorionic fluid where nanoscale materials have been observed. [173] Moreover, the study of Ong et al [47] is one of very few to directly compare the toxicity of uncoated and coated NMs where they found minor effects on hatch in embryos exposed to polyacrylic acid stabilised ZnO NMs, further suggesting that Zn 2þ dissolution dominates as the source of hatch impairment and therefore it is difficult to define the role of colloidal NM interaction with the hatching enzyme in Zn 2þ -containing NMs. [47] Although the role of released Zn 2þ towards toxicity has not been fully resolved, Zn 2þ appears to have greater bioavailability than nanoscale ZnO.…”