Release of engineered nanomaterials from personal care products throughout their life cycle

The impetus for this study was to provide release estimates that can serve to improve predictions of engineered nanomaterial (ENM) exposure for risk assessment. We determined the likely release of ENMs from personal care products (PCPs) through a consumer survey on use and disposal habits, and research on the types and quantities of ENMs in PCPs. Our estimates show that in the US zinc oxide (ZnO), with 1,800-2,100 mt yr-1, and titanium dioxide (TiO2), with 870-1,000 mt yr-1, represent 94 % of ENMs released into the environment or landfills from the use of PCPs. Around 36-43 % of ENMs from PCPs were estimated to end up in landfills, 24-36 % released to soils, 0.7-0.8 % to air, and 28-32 % to water bodies. ENMs in sunscreen represent around 81-82 % of total release, from ZnO and TiO2 as UV blockers, followed by facial moisturizer (7.5 %), foundation (5.7 %), and hair coloring products (3.1 %). Daily care products such as body wash, shampoo, and conditioner had by far the highest per capita and total use, but contributed little to the ENM release estimates as these products generally contain little or no ENMs. However, if ENMs are incorporated into these daily care products, this may substantially increase ENM release. © 2014 Springer Science+Business Media

Surface coatings of ZnO nanoparticles mitigate differentially a host of transcriptional, protein and signalling responses in primary human olfactory cells

Background: Inhaled nanoparticles have been reported in some instances to translocate from the nostril to the olfactory bulb in exposed rats. In close proximity to the olfactory bulb is the olfactory mucosa, within which resides a niche of multipotent cells. Cells isolated from this area may provide a relevant in vitro system to investigate potential effects of workplace exposure to inhaled zinc oxide nanoparticles. Methods: Four types of commercially-available zinc oxide (ZnO) nanoparticles, two coated and two uncoated, were examined for their effects on primary human cells cultured from the olfactory mucosa. Human olfactory neurosphere-derived (hONS) cells from healthy adult donors were analyzed for modulation of cytokine levels, activation of intracellular signalling pathways, changes in gene-expression patterns across the whole genome, and compromised cellular function over a 24 h period following exposure to the nanoparticles suspended in cell culture medium. Results: ZnO nanoparticle toxicity in hONS cells was mediated through a battery of mechanisms largely related to cell stress, inflammatory response and apoptosis, but not activation of mechanisms that repair damaged DNA. Surface coatings on the ZnO nanoparticles mitigated these cellular responses to varying degrees. Conclusions: The results indicate that care should be taken in the workplace to minimize generation of, and exposure to, aerosols of uncoated ZnO nanoparticles, given the adverse responses reported here using multipotent cells derived from the olfactory mucosa

Minimal oxidation and inflammogenicity of pristine graphene with residence in the lung

Two-dimensional graphitic carbon, graphene, is a new form of nanomaterial with great potential in a wide variety of applications. It is therefore crucial to investigate the behaviour of graphene in biological systems to assess potential adverse effects that might follow from inhalation exposure. In this study we focussed on medium-term effects of graphene in lung tissue by investigating the pulmonary inflammation 6 weeks after pharyngeal aspiration of unoxidised multilayered graphene platelets (GPs) in mice and assessed their biopersistence in the lung tissue using Raman spectroscopy. Additionally, GP degradation in vitro was examined after horseradish peroxidase (HRP) treatment up to 1 week. Building on our previous report showing acute inflammation in mice lungs at 1 day, pristine GP showed minimal inflammation in mouse lungs after 6 weeks even though no degradation of GP in lung tissue was observed and large deposits of GP were evident in the lungs. Raman analysis of GP in tissue sections showed minimal oxidation, and in vitro examinations of enzymatic oxidation of GP via HRP and H2O2 showed only slight increases in ID/IG ratio and the appearance of the Raman D' band at 1620 cm-1 (surrogates of graphene oxidation). Our results showing non-inflammogenicity at medium time points have important implications in the hazard identification of GPs following inhalation exposure and for their use in biomedical applications. Additionally, the biopersistence of pristine GP in vivo with no associated inflammation could open the way to applications in tissue engineering and drug delivery