Enhanced Dark-Field Hyperspectral Imaging and Spectral Angle Mapping for Nanomaterial Detection in Consumer Care Products and in Skin Following Dermal Exposure
- DOI
- Language of the publication
- English
- Date
- 2020-04-27
- Type
- Article
- Author(s)
- Boyadzhiev, Andrey
- Trevithick-Sutton, Colleen
- Wu, Dongmei
- Decan, Nathalie
- Bazin, Marc
- Shah, Girish, M.
- Halappanavar, Sabina
- Publisher
- American Chemical Society
Abstract
Consumer personal care products, and cosmetics containing nanomaterials (NM), are increasingly available in the Canadian market. Current Canadian regulations do not require product labeling for ingredients that are present in the nanoscale. As a result, unless voluntarily disclosed, it is unclear which products contain NM. The enhanced dark-field hyperspectral imaging (EDF-HSI) coupled with spectral angle mapping (SAM) is a recent technique that has shown much promise for detection of NM in complex matrices. In the present study, EDF-HSI was used to screen cosmetic inventories for the presence of nano silver (nAg), nano gold (nAu), and nano titanium dioxide (nTiO2). In addition, we also assessed the potential of EDF-HSI as a tool to detect NM in skin layers following application of NM products in vitro on commercially available artificial skin constructs (ASCs) and in vivo on albino hairless SKH-1 mouse skin. Spectroscopic analysis positively detected nAu (4/9 products) and nTiO2 (7/13 products), but no nAg (0/6 products) in a subset of the cosmetics. The exposure of ASCs for 24 h in a Franz diffusion cell system to a diluted cosmetic containing nTiO2 revealed penetrance of nTiO2 through the epidermal layers and was detectable in the receptor fluid. Moreover, both single and multiple applications of nTiO2 containing cosmetics on the dorsal surface of SKH-1 mice resulted in detectable levels of trace nTiO2 in the layers of the skin indicating that penetrance of NM was occurring after each application of the product. The current study demonstrates the sensitivity of EDF-HSI with SAM mapping for qualitative detection of NM present in cosmetic products per se and very low levels in complex biological matrices on which these products are applied.
Plain language summary
Health Canada is responsible for the assessment and management of health risks to Canadians associated with exposure to chemicals and emerging substances such as nanomaterials. Nanomaterials (NM, small materials with size range between 1 – 100 nanometers, 1 nanometer is a billionth of a meter) are becoming more common in a wide range of consumer products including personal care products and cosmetics in Canada. Early studies have shown that some NM have the potential to induce toxicity when inhaled in high doses but less is known on dermal routes of exposure through skin application of NM-containing products, such as cosmetics and sun tan lotions. Currently, cosmetic regulations under Canada’s Food and Drugs Act do not require specific identification of ingredients present in the nanoscale but Health Canada is anticipated to conduct health risk assessments on NM. Therefore, it is imperative that rapid and sensitive screening techniques are made available to assist in detecting NMs present in consumer products in order to inform risk assessment. In this study, an advanced microscopic imaging methodology was optimised to sensitively detect nano gold, silver, and titanium dioxide in cosmetics present in the Canadian market; and further, to detect nano titanium dioxide within mouse skin and artificial skin constructs following treatment with a nano titanium dioxide containing cosmetic. The findings of this study provide support for the use of this technique as an effective screening method to aid exposure and risk assessment of NM contained in personal care products.
Subject
- Health,
- Health and safety