Biodistribution and pulmonary toxicity of intratracheally instilled graphene oxide in mice

Graphene and its derivatives (for example, nanoscale graphene oxide (NGO)) have emerged as extremely attractive nanomaterials for a wide range of applications, including diagnostics and therapeutics. In this work, we present a systematic study on the in vivo distribution and pulmonary toxicity of NGO for up to 3 months after exposure. Radioisotope tracing and morphological observation demonstrated that intratracheally instilled NGO was mainly retained in the lung. NGO could result in acute lung injury (ALI) and chronic pulmonary fibrosis. Such NGO-induced ALI was related to oxidative stress and could effectively be relieved with dexamethasone treatment. In addition, we found that the biodistribution of I-125-NGO varied greatly from that of I-125 ions, hence it is possible that nanoparticulates could deliver radioactive isotopes deep into the lung, which might settle in numerous 'hot spots' that could result in mutations and cancers, raising environmental concerns about the large-scale production of graphene oxide. NPG Asia Materials (2013) 5, e44; doi:10.1038/am.2013.7; published online 5 April 2013