Surface Characteristics, Copper Release, and Toxicity of Nano‐ and Micrometer‐Sized Copper and Copper(II) Oxide Particles: A Cross‐Disciplinary Study

TLDR

The study assessed the toxic effects of thoroughly characterized nano‑ and micrometer‑sized oxidized copper and copper(II) oxide particles on cultivated lung cells and measured copper release in relevant media. An interdisciplinary, multianalytical approach was used to evaluate particle toxicity and copper release dynamics. Findings revealed that, except for micrometer‑sized Cu, all particles released more copper in serum‑containing medium than in PBS, sonication markedly increased initial copper release, and a clear size‑dependent effect emerged: nanometer‑sized particles released more copper, caused greater DNA damage and higher cell death, whereas cytotoxicity from released copper alone was lower and did not induce DNA damage.

Abstract

An interdisciplinary and multianalytical research effort is undertaken to assess the toxic aspects of thoroughly characterized nano- and micrometer-sized particles of oxidized metallic copper and copper(II) oxide in contact with cultivated lung cells, as well as copper release in relevant media. All particles, except micrometer-sized Cu, release more copper in serum-containing cell medium (supplemented Dulbecco's minimal essential medium) compared to identical exposures in phosphate-buffered saline. Sonication of particles for dispersion prior to exposure has a large effect on the initial copper release from Cu nanoparticles. A clear size-dependent effect is observed from both a copper release and a toxicity perspective. In agreement with greater released amounts of copper per quantity of particles from the nanometer-sized particles compared to the micrometer-sized particles, the nanometer particles cause a higher degree of DNA damage (single-strand breaks) and cause a significantly higher percentage of cell death compared to cytotoxicity induced by micrometer-sized particles. Cytotoxic effects related to the released copper fraction are found to be significantly lower than the effects related to particles. No DNA damage is induced by the released copper fraction.