In recent years,graphene and its derivatives(such as graphene oxide,GO)have received much attention for their unique physiochemical properties; graphene materials have a broad range of potential applications,especially in the biomedical field.However,graphene and GO nanosheets have been reported to possess cytotoxic effects.In this work,we have studied the biological effects of GO nanosheets for human lung adenocarcinoma cells(A549 cells).