Mona Connolly - Academia.edu (original) (raw)

Papers by Mona Connolly

Abstract: Among all classes of nanomaterials, silver nanoparticles (AgNPs) have potentially an im... more Abstract: Among all classes of nanomaterials, silver nanoparticles (AgNPs) have potentially an important ecotoxicological impact, especially in freshwater environments. Fish are particularly susceptible to the toxic effects of silver ions and, with knowledge gaps regarding the contribution of dissolution and unique particle effects to AgNP toxicity, they represent a group of vulnerable organisms. Using cell lines (RTL-W1, RTH-149, RTG-2) and primary hepatocytes of rainbow trout (Oncorhynchus mykiss) as in vitro test systems, we assessed the cytotoxicity of the representative AgNP, NM-300K, and AgNO3 as an Ag+ ion source. Lack of AgNP interference with the cytotoxicity assays (AlamarBlue, CFDA-AM, NRU assay) and their simultaneous application point to the compatibility and usefulness of such a battery of assays. The RTH-149 and RTL-W1 liver cell lines exhibited similar sensitivity as primary hepatocytes towards AgNP toxicity. Leibovitz’s L-15 culture medium composition (high amino ac...

Environmental Toxicology and Chemistry

Environmental Sciences Europe

Background This study was conducted to provide much needed information on the potential of low so... more Background This study was conducted to provide much needed information on the potential of low solubility, highly biodurable nanoparticles (NPs) (TiO2 and CeO2 NPs), to bioaccumulate in fish and to investigate the relationship between an engineered nanomaterials surface coating, uptake and biokinetics in vivo. Rainbow trout (Oncorhynchus mykiss) were fed diets spiked with uncoated or surface coated (polyethylene glycol (PEG) or citrate (CIT)) TiO2 and CeO2 NPs (100 mg NPs/kg feed) for 10 days and thereafter fish were allowed to depurate for 42 days. Special care was taken to measure the real dispersed and actual administered concentrations, taking into consideration any potential losses from leaching, and to characterise the form (size, aggregation state, charge) of the NPs to which the fish were exposed. Results The coatings had an influence on levels of uptake and distributions. Most notably a higher uptake of PEG and CIT coated TiO2 and CeO2 NPs compared to fish exposed to uncoat...

Desde que se descubrio a inicios del siglo XXI que materiales conocidos, tales como los metales, ... more Desde que se descubrio a inicios del siglo XXI que materiales conocidos, tales como los metales, sintetizados en escala nanometrica, presentaban propiedades extraordinarias y sorprendentes, que podrian ser muy beneficiosas y remodelar nuestro futuro, el numero de nuevos materiales ha ido aumentando de forma exponencial. Los nanomateriales manufacturados (NMs) son materiales sintetizados por el hombre constituidos por particulas que poseen en al menos una de sus dimensiones un tamano de entre 1 y 100 nm (ISO, 2016; EU, 2011). Este tamano es importante desde un punto de vista regulatorio pero, en realidad, cuando se trabaja en el laboratorio estos limites se desdibujan pudiendo hablar de NMs de algunos cientos de nms. En cualquier caso, antes de que el potencial de estos NMs pueda ser conocido por completo, es responsabilidad nuestra asegurar que todo el proceso de desarrollo lleve a la fabricacion de materiales seguros. Como consecuencia de esta necesidad ha surgido la nanotoxicologi...

MethodsX

The first step of nanomaterial accumulation in the aquatic environment is the uptake of particula... more The first step of nanomaterial accumulation in the aquatic environment is the uptake of particulate material. For substances with very low water solubility, exposure via water may be of limited relevance in comparison to the dietary route. The OECD Test Guideline 305 for bioaccumulation testing in fish using dietary exposure recommends to add substances to fish food following methodologies normally used in aquaculture (e.g. with a corn or fish oil vehicle). The feasibility of using such an approach for the testing of manufactured nanomaterials (MNs), due to their unique physical characteristics and solubility, needs to be investigated. In this study an easy, cost-effective method to prepare metal oxide nanoparticle (NP) spiked feed to give the required dietary exposure concentration to fish is described. Metal oxide NP (CeO2,TiO2 and ZnO) dispersions were prepared in oil (sunflower or olive oil) and used to soak fish feed pellets. NP surface deposition and homogeneity of distribution were analysed and confirmed. Discrepancies between nominal and measured concentrations highlighted the need to measure the achieved concentration in MN-spiked feed. The present method provides stable concentrations for bioaccumulation testing of MNs in fish through the dietary route. A method for• Fish feed preparation using nanomaterial-oil suspensions.• Homogenous spiking of nanomaterials on feed.• Nanomaterials stably maintained on feed immersed in water until eaten by fish.

Polymer Degradation and Stability

Abstract The exploitation of polylactide (PLA) nanocomposites (which integrate organically modifi... more Abstract The exploitation of polylactide (PLA) nanocomposites (which integrate organically modified clays (organoclays) into polymers) in packaging for the cosmetics industry could provide a biodegradable alternative to the use of conventional plastics. In this study nanocomposites with a PLA polymer matrix and clay fillers organically modified with the quaternary ammonium salts, hexadecyl trimethyl ammonium bromide (HDTA) or octadecyl trimethyl ammonium chloride (TMSA), were produced and tested for their safe use in cosmetic packaging. To address concerns over the potential release of constituents from such nanocomposites, levels of total overall migration in a range of simulants (e.g. vegetable oil, aqueous media, and cosmetic formulations) was assessed 10 days post incubation at 40 °C following EU-Plastics Regulation 10/2011 concerning materials and articles in contact with foodstuffs. Total overall migration levels calculated for all PLA nanocomposites tested (maximum of 0.88 ± 0.44 mg/dm2) were well below the total established legislative migration limit (10 mg/dm2). Toxicity of the nanocomposite migration extracts to the skin was assessed in vitro. Exposure of skin cells (HaCaT immortalized human keratinocytes) and a full thickness epidermal skin model (EpiDerm™) to migration extracts did not result in any significant loss in cell viability or skin irritation (OECD TG 439). The results therefore indicate that the levels of migration from the nanocomposite measured was low, and that the nanocomposite migration extracts stimulated minimal toxicity to the skin. Up until now, the hazard of migration extracts from polymer-organoclay nanocomposites following dermal exposure has not been investigated and thus our study addresses a gap in knowledge. These findings can inform the safe design of bio-based biodegradable nanocomposite packaging (used by the cosmetics, and other industries) in the future to promote a more sustainable and greener economy for the plastics industry.

Food and Chemical Toxicology

The influence of organic modification on the cytotoxicity of clay particles to keratinocytes, hep... more The influence of organic modification on the cytotoxicity of clay particles to keratinocytes, hepatocytes and macrophages; an investigation towards the safe use of polymer-clay nanocomposite packaging

Ecotoxicology and environmental safety, 2017

Titanium dioxide nanoparticles (TiO2-NPs) have a wide number of applications in cosmetic, solar a... more Titanium dioxide nanoparticles (TiO2-NPs) have a wide number of applications in cosmetic, solar and paint industries due to their photocatalyst and ultraviolet blocking properties. The continuous increase in the production of TiO2-NPs enhances the risk for this manufactured nanomaterial to enter water bodies through treated effluents or agricultural amendments. TiO2-NPs have shown very low toxicity in a number of aquatic organisms. However, there are no conclusive data about their deleterious effects and on their possible mechanisms of toxic action. At this level, in vitro cell culture systems are a useful tool to gain insight about processes underlying the toxicity of a wide variety of substances, including nanomaterials. Differences in the physiology of different taxa make advisable the use of cells coming from the taxon of interest, but collecting data from a variety of cellular types allows a better understanding of the studied processes. Taking all this into account, the aim of...

Science of The Total Environment, 2016

The increasing use of ZnO nanoparticles (ZnO NPs) in different fields has raised concerns about t... more The increasing use of ZnO nanoparticles (ZnO NPs) in different fields has raised concerns about the possible environmental risks associated with these NPs entering aquatic systems. In this study, using a dietary exposure route, we have analysed the tissue distribution and depuration pattern of Zn as well as any associated redox balance disturbances in rainbow trout (Oncorhynchus mykiss) following exposure to ZnO NPs (20-30nm). Fish were fed a diet spiked with ZnO NPs prepared from a dispersion in sunflower oil at doses of 300 or 1000mg ZnO NPs/kg feed for 10days. This uptake phase was followed by a 28days depuration phase in which fish from all groups received untreated feed. While no overt signs of toxicity were observed and no important effects in fish growth (weight and length) or in the hepatosomatic index among groups were recorded, we observed high levels of Zn bioaccumulation in the gills and intestine of exposed fish following exposure to both dose levels. Zn levels were not eliminated during the depuration phase and we have evidenced oxidative stress responses in gills associated with such long term ZnO NPs bioaccumulation and lack of elimination. Furthermore, exposures to higher doses of ZnO NPs (1000mg/kg feed) resulted in Zn distribution to the liver of fish following 10days of exposure. Fish from this exposure group experienced biochemical disturbances associated with oxidative stress in the liver and ethoxy-resorufin-O-deethylase (EROD) activity which may point to the ability of ZnO NPs or its ions to interfere with cytochrome P450 metabolic processes.

International Journal of Environmental Research and Public Health, 2015

Chemico-biological interactions, Jan 25, 2015

The generation of reactive oxygen species (ROS) and consequent oxidative stress is regarded as a ... more The generation of reactive oxygen species (ROS) and consequent oxidative stress is regarded as a relevant mechanism for nanoparticle toxicity. In cells, the activation of the aryl hydrocarbon receptor (AhR) triggers a cascade of defence responses against oxidative stress. By increasing AhR dependent cellular anti-oxidant activity, we tested the extent to which the cytotoxic effect of copper nanoparticles (CuNPs) is governed by oxidative stress. H4IIE rat hepatoma cells were challenged with high ROS levels after exposure to CuNPs, while the AhR-induced cellular anti-oxidant defence was simultaneously activated by the AhR ligand beta-Naphthoflavone (ßNF). Activation of phase II detoxification enzymes (as glutathione-S-transferases, GSTs) and anti-oxidants (glutathione, GSH) led to a complete abrogation of CuNP-induced ROS production. However, a concurrent reduction in cytotoxicity was not detected, thereby indicating that CuNPs exert non-oxidative stress mediated cytotoxic effects. Tr...

Science of The Total Environment, 2015

Journal of Nanoparticle Research, 2015

ABSTRACT Here, the effects of incubation temperature and particle size on the dissolution and agg... more ABSTRACT Here, the effects of incubation temperature and particle size on the dissolution and aggregation behavior of copper nanoparticles (CuNPs) in culture media were investigated over 96 h, equivalent to the time period for acute cell toxicity tests. Three CuNPs with the nominal sizes of 25, 50, and 100 nm and one type of micro-sized particles (MPs, ~500 nm) were examined in culture media used for human and fish hepatoma cell lines acute tests. A large decrease in sizes of CuNPs in the culture media was observed in the first 24 h incubation, and subsequently the sizes of CuNPs changed slightly over the following 72 h. Moreover, the decreasing rate in size was significantly dependent on the incubation temperature; the higher the incubation temperature, the larger the decreasing rate in size. In addition to that, we also found that the release of copper ions depended on the incubation temperature. Moreover, the dissolution rate of Cu particles increased very fast in the first 24 h, with a slight increase over the following 72 h.

Nanoscale Research Letters, 2013