Are Nontoxic Nanoparticles Really Nontoxic?

Nanoparticles coated with transferrin have been shown to kill a certain type of lymphoma cell, an unexpected result that raises some doubts about the assumed nontoxicity of carrier nanoparticles.

Investigators at the University of North Carolina (Chapel Hill, USA) had been working with transferrin-coated nanoparticles as carriers for anticancer drugs directed at tumor cells that overexpressed the transferrin receptor on their cell membranes. The transferrin-coated nanoparticles were prepared by the PRINT (Particle Replication in Non-wetting Templates) technique, which produces nanoparticles with well-defined size and shape. Previous studies had shown that as carriers the transferrin-coated nanoparticles could recognize safely and accurately a broad spectrum of cancers including B-cell lymphoma and non-small-cell lung cancer as well as ovarian, liver, and prostate cancer cells.

In the current study, which was published in the July 27, 2010 online edition of the Journal of the American Chemical Society, the investigators found that nanoparticles coated either with transferrin or an antibody against the transferrin receptor – but without any anticancer drug attached – were able to readily kill Ramos B-cell lymphoma. Neither free transferrin nor unbound antibody was toxic.

"Although this is potentially exciting for the development of entirely new strategies for treating certain types of lymphomas with potentially lower side effects, this study also raises concerns for unanticipated off-target effects when one is designing targeted chemotherapy agents for other types of cancers,” said senior author Dr. Joseph M. DeSimone, professor of medicine at the University of North Carolina.

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