Are Diamond Nanoparticles Cytotoxic?

TLDR

Carbon particles, including historic tattoo pigments and modern nanodiamonds, have long been used ornamentally, and recent advances in nanoscience have highlighted nanodiamonds’ low reactivity and unique properties, making them attractive for drug delivery, imaging, implant coatings, and biosensing. The study aims to determine whether nanodiamonds pose cytotoxic risks to human and other biological systems. The authors evaluated cytotoxicity of 2–10 nm nanodiamonds using cell viability assays. Cell viability assays (MTT, ATP) and ROS measurements revealed that 2–10 nm nanodiamonds are non‑toxic, do not induce reactive oxygen species, and support normal cell growth on coated substrates, indicating suitability for diverse biological applications.

Abstract

Finely divided carbon particles, including charcoal, lampblack, and diamond particles, have been used for ornamental and official tattoos since ancient times. With the recent development in nanoscience and nanotechnology, carbon-based nanomaterials (e.g., fullerenes, nanotubes, nanodiamonds) attract a great deal of interest. Owing to their low chemical reactivity and unique physical properties, nanodiamonds could be useful in a variety of biological applications such as carriers for drugs, genes, or proteins; novel imaging techniques; coatings for implantable materials; and biosensors and biomedical nanorobots. Therefore, it is essential to ascertain the possible hazards of nanodiamonds to humans and other biological systems. We have, for the first time, assessed the cytotoxicity of nanodiamonds ranging in size from 2 to 10 nm. Assays of cell viability such as mitochondrial function (MTT) and luminescent ATP production showed that nanodiamonds were not toxic to a variety of cell types. Furthermore, nanodiamonds did not produce significant reactive oxygen species. Cells can grow on nanodiamond-coated substrates without morphological changes compared to controls. These results suggest that nanodiamonds could be ideal for many biological applications in a diverse range of cell types.