ELECTROSPRAYING OF FERRITIN SOLUTIONS FOR THE PRODUCTION OF MONODISPERSE IRON OXIDE NANOPARTICLES

Abstract

Iron oxide nanoparticles with uniform size and narrow size distribution were synthesized by electrospraying of ferritin and subsequent heat treatment at 800°, 850°, and 900°C. Solutions of ferritin in both water and water/iso-propanol mixture (50:50) were electrosprayed in diverse gaseous environments. Narrow mobility size distributions with a mean mobility diameter of 4.5 nm and a geometric standard deviation < 1.2 were obtained at 800°C. The process of aerosol formation involved the thermal oxidation of the ferritin organic shell. The utilization of a water/iso-propanol (50:50) ferritin solution led to the establishment of a more stable electrospray, and, consequently, an increase in the total particle concentration was observed. Furthermore, carbon-coated magnetite (Fe ₃ O ₄) particles were generated when CO was used as carrier gas.

Keywords:

• Electrospray
• Ferritin
• Iron oxide nanoparticles

Acknowledgments

Mr. Raoul Järvinen is gratefully acknowledged for assistance in building the experimental system. The authors also thank Dr. Unto Tapper and Dr. David P. Brown for interesting discussions and proofreading the manuscript, respectively. This work was supported by the Academy of Finland and the European Community Research Training Network “Nanocluster” (grant No. HPRN-CT-2002-00328).