Manipulation of single magnetic protein particles using atomic force microscopy

Horse-spleen ferritin has recently gained much attention as a nanoscale magnet that demonstrates macroscopic quantum tunneling of its magnetization through the anisotropy barrier. The size of the protein is ideal for the identification and manipulation of single particles using scanned-probe techniques. We demonstrate that accurate positioning of individual, surface-trapped horse-spleen particles can be achieved by mechanical pushing with the tip of an atomic force microscope. This technique offers a route to the incorporation of single ferritin particles as components in future nanoscale devices. (C) 2003 Elsevier B.V. All rights reserved.