title: Nanoparticle cytotoxicity depends on intracellular solubility: comparison of stabilized copper metal and degradable copper oxide nanoparticles.
abstract: Metal nanoparticles have distinctly different chemical and physical properties than currently investigated oxides. Since pure metallic nanoparticles are igniting at air, carbon stabilized copper nanoparticles were used as representative material for this class. Using copper as a representative example, we compare the cytotoxicity of copper metal nanoparticles stabilized by a carbon layer to copper oxide nanoparticles using two different cell lines. Keeping the copper exposure dose constant, the two forms of copper showed a distinctly different response. Whilst copper oxide had already been reported to be highly cytotoxic, carbon-coated copper nanoparticles were much less cytotoxic and more tolerated. Measuring the two material's intra- and extracellular solubility in model buffers explained this difference on the basis of altered copper release when supplying copper metal or the corresponding oxide particles to the cells. Control experiments using pure carbon nanoparticles were used to exclude significant surface effects. Reference experiments with ionic copper solutions confirmed a similar response of cultures if exposed to copper oxide nanoparticles or ionic copper. These observations are in line with a Trojan horse-type mechanism and illustrate the dominating influence of physico-chemical parameters on the cytotoxicity of a given metal.
authors.affiliation: Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Studer
authors.forename: Ludwig K
authors.initials: LK
authors.lastname: Limbach
authors.forename: Luu
authors.initials: L
authors.lastname: Van Duc
authors.forename: Frank
authors.initials: F
authors.lastname: Krumeich
authors.forename: Evagelos K
authors.initials: EK
authors.lastname: Athanassiou
authors.forename: Lukas C
authors.initials: LC
authors.lastname: Gerber
authors.forename: Holger
authors.initials: H
authors.lastname: Moch
authors.forename: Wendelin J
authors.initials: WJ
authors.lastname: Stark
mesh_terms: D000818:Animals; D016466:CHO Cells; D003300:Copper / Q000737:chemistry / Q000633:toxicity*; D006224:Cricetinae; D003412:Cricetulus; D006367:HeLa Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000633:toxicity*
chemical_list: D003300:Copper; C030973:cupric oxide