Direct amine-functionalisation of γ-Fe2O3 nanoparticles

Abstract

A novel and simple preparation of amine-modified γ-Fe₂O₃ nanoparticles is described. The presence of amine groups on the surface, instead of hydroxyl groups, will allow conjugation of biologically active molecules to the iron oxide nanoparticles without the need for a size increasing silica shell. Furthermore, the outer amine-layer increases the temperature of the γ-Fe₂O₃ to α-Fe₂O₃ structural transition in a similar way to previously reported cationic substitutions. This may suggest the formation of an oxide–nitride outer layer. Re-dispersion of the amine-modified γ-Fe₂O₃ nanoparticles led to the preparation of stable ferrofluids.