The effect of γ-Fe2O3 nanoparticles on Escherichia coli genome

► Obvious bacterial genomic variations were observed under γ-Fe2O3 magnetic nanoparticles (MNPs) addition. ► It was revealed that bioavailable Fe3+ increased in the medium with MNPs addition. ► Cellular uptake of MNPs was observed when E. coli was incubated with MNPs. ► Both increased Fe3+ ion and the uptake of MNPs could be responsible for such genomic responses.