Copper Leachability from Cu Nanoparticle-Containing Face Masks and Associated Subcellular Impacts

As a consequence of the COVID-19 pandemic, billions of people wear face masks for hours on a daily basis. However, whether hazardous materials released from the face masks might pose potential risks to human health remains mostly unexplored. In particular, nanoparticle-containing face masks have become popular in the market due to their improved antiviral and antibacterial effects. The leachability of nanoparticles and any subsequent toxicity are largely unknown. This study is the first to evaluate the Cu leachability from a face mask containing Cu nanoparticles and the subsequent cytotoxicity of the leachate. We showed that similar to 20 μg of Cu in the mask was inhaled, accounting for almost 3% of the total Cu. Moreover, 30-40% of the Cu attached to fibers from the mask could be easily released into solution, and most of the released Cu existed in ionic forms. Cell-based testing indicated that although the leachate did not induce any cytotoxicity, it caused significant Cu stress leading to the exocytosis of lysosomes, changes in glutathione concentration, and the generation of reactive oxygen species. Overall, our results suggest that the leachability of nanoparticle-containing face masks should be carefully assessed, especially considering that most nanoparticle-containing face masks are recommended to be reusable after being washed. © 2023 American Chemical Society