Background: Fe3O4 nanoparticles have wide applications in biomedical researches. Purpose: The aim is to study the Fe3O4 nanoparticle-protein interactions and their bioeffects. Methods: Transmission electron microscope (TEM)

light microscopy

SDS-PAGE (Sodium Dodecyl Sulfonate-Polyacrylamide Gelelectrophoresis)

Bradford and MTT (3-(4

5-dimethyl-2-thiazolyl)-2

5-diphenyl-2-H-tetrazolium bromide) methods were used to investigate the Fe3O4 nanoparticle-protein interactions and their bioeffects. Results: The adsorption capacities of Fe3O4 nanoparticle for different proteins were different

and the order was fibrinogen>immunoglobulin>albumin. The adsorption of proteins on the Fe3O4 surface resulted in much reduced cytotoxicity for these protein-coated Fe3O4 nanoparticles. Conclusion: These findings suggest that we should take the Fe3O4 nanoparticle-protein interactions into consideration when designing safe Fe3O4 nanoparticles for biomedical applications. Abstract