Characterization of an aerosol generation system to assess inhalation risks of aerosolized nano-enabled consumer products

Analytical and toxicological aspects of nanomaterials in different product groups: Challenges and opportunities

The widespread integration of engineered nanomaterials into consumer and industrial products creates new challenges and requires innovative approaches in terms of design, testing, reliability, and safety of nanotechnology. The aim of this review article is to give an overview of different product groups in which nanomaterials are present and outline their safety aspects for consumers. Here, release of nanomaterials and related analytical challenges and solutions as well as toxicological considerations, such as dose-metrics, are discussed. Additionally, the utilization of engineered nanomaterials as pharmaceuticals or nutraceuticals to deliver and release cargo molecules is covered. Furthermore, critical pathways for human exposure to nanomaterials, namely inhalation and ingestion, are discussed in the context of risk assessment. Analysis of NMs in food, innovative medicine or food contact materials is discussed. Specific focus is on the presence and release of nanomaterials, including whether nanomaterials can migrate from polymer nanocomposites used in food contact materials. With regard to the toxicology and toxicokinetics of nanomaterials, aspects of dose metrics of inhalation toxicity as well as ingestion toxicology and comparison between in vitro and in vivo conclusions are considered. The definition of dose descriptors to be applied in toxicological testing is emphasized. In relation to potential exposure from different products, opportunities arising from the use of advanced analytical techniques in more unique scenarios such as release of nanomaterials from medical devices such as orthopedic implants are addressed. Alongside higher product performance and complexity, further challenges regarding material characterization and safety, as well as acceptance by the general public are expected.

Potential consumer exposure to respirable particles and TiO2 due to the use of eyebrow powders

BACKGROUND

Cosmetic powders contain numerous components, including titanium dioxide (TiO2), which is classified as possibly carcinogenic to humans (Group 2B). However, little is known about potential inhalation exposures to particles that are released during cosmetic powder applications.

METHODS

We realistically simulated the application of five different eyebrow powders using a mannequin and then determined concentrations of total suspended particles (TSP), PM10, and PM4 fractions of particles that would be inhaled during powder application. We determined the size and shape of particles in the original powders and released particles, as well as their TiO2 concentrations and Ti content of individual particles.

RESULTS

The application of eyebrow powders resulted in the release and inhalation of airborne particles at concentrations ranging from 21.2 to 277.3 µg/m3, depending on the particle fraction and the powder. The concentrations of TiO2 in PM4 and PM10 samples reached 2.7 µg/m3 and 9.3 µg/m3, respectively. The concentration of TiO2 in airborne particle fractions was proportional to the presence of TiO2 in the bulk powder.

CONCLUSION

The application of eyebrow powders results in user exposures to respirable PM4 and PM10 particles, including those containing TiO2. This information should be of interest to stakeholders concerned about inhalation exposure to TiO2.

Induction of Oxidative DNA Damage and Epithelial Mesenchymal Transitions in Small Airway Epithelial Cells Exposed to Cosmetic Aerosols

Engineered metal nanoparticles (ENPs) are frequently incorporated into aerosolized consumer products, known as nano-enabled products (NEPs). Concern for consumer pulmonary exposures grows as NEPs produce high concentrations of chemically modified ENPs. A significant knowledge gap still exists surrounding NEP aerosol respiratory effects as previous research focuses on pristine/unmodified ENPs. Our research evaluated metal-containing aerosols emitted from nano-enabled cosmetics and their induction of oxidative stress and DNA damage, which may contribute to epithelial mesenchymal transitions (EMT) within primary human small airway epithelial cells. We utilized an automated NEP generation system to monitor and gravimetrically collect aerosols from two aerosolized cosmetic lines. Aerosol monitoring data were inputted into modeling software to determine potential inhaled dose and in vitro concentrations. Toxicological profiles of aerosols and comparable pristine ENPs (TiO2 and Fe2O3) were used to assess reactive oxygen species and oxidative stress by fluorescent-based assays. Single-stranded DNA (ssDNA) damage and 8-oxoguanine were detected using the CometChip assay after 24-h exposure. Western blots were conducted after 21-day exposure to evaluate modulation of EMT markers. Results indicated aerosols possessed primarily ultrafine particles largely depositing in tracheobronchial lung regions. Significant increases in oxidative stress, ssDNA damage, and 8-oxoguanine were detected post-exposure to aerosols versus pristine ENPs. Western blots revealed statistically significant decreases in E-cadherin and increases in vimentin, fascin, and CD44 for two aerosols, indicating EMT. This work suggests certain prolonged NEP inhalation exposures cause oxidative DNA damage, which may play a role in cellular changes associated with reduced respiratory function and should be of concern.