Cobalt Nanoparticles

BrooklynDodger(s) comment: Once again, hazard identification without a measure of potency. Each time a new effect is discovered - in this case migration of particles into the cell - it justifies taking previously identified materials through the same assay. Problem is, every lab has it's own pet assay.


Toxicology Letters
Volume 189, Issue 3, 28 September 2009, Pages 253-259

Engineered cobalt oxide nanoparticles readily enter cells

Elena Papisa, Federica Rossia, Mario Raspantib, Isabella Dalle-Donnec, Graziano Colomboc, Aldo Milzanic, Giovanni Bernardinia, d and Rosalba Gornatia, Corresponding Author Contact Information, E-mail The Corresponding Author

aDepartment of Biotechnology and Molecular Science, Insubria University, Varese, Italy

bDepartment of Human Morphology, Insubria University, Varese, Italy

cDepartment of Biology, University of Milan, Milano, Italy

dCentro di Ricerca Interuniversitario Politecnico di Milano e Università dell’Insubria “The Protein Factory”, Italy

Abstract

Magnetic nanoparticles (NPs) have great potential for applications not only as catalysts or energy storage devices, but also in biomedicine, as contrast enhancement agents for magnetic resonance imaging, or for drug delivery. The same characteristics that make cobalt-based NPs so attractive raise serious questions about their safety. In this context, we investigated Co3O4-NPs. Believing that the characterization of NPs is relevant for understanding their biological activity, we analyzed them by atomic force and electron microscopy to define size, shape, and aggregation. To clarify whether their biological effects could be due to a potential release of cobalt ions, we evaluated spontaneous dissolution in different media. To determine their potential toxicity to human cells, we measured cell viability and ROS formation in two human cell lines using CoCl2 for comparison. Co3O4-NPs induced a concentration- and time-dependent impairment of cellular viability, although cobalt ions were more toxic. We also demonstrated that cobalt causes a rapid induction of ROS if supplied in the form of Co3O4-NPs rather than as ions. Moreover, we evaluated the cellular uptake of NPs. Interestingly, Co3O4-NPs are able to enter the cell very rapidly, remaining confined in vesicles inside the cytoplasm. They were found also inside the cell nuclei, though less frequently.