MICROFABRICATION OF MAGNETIC MICRO-GRIPPERS AND THEIR NAVIGATION USING MRI SYSTEM

Abstract

In the recent decades, magnetic resonance imaging (MRI) has become one of the most important technologies in medical science that can provide a safe, convenient and high-quality imaging of the human body. By exploiting the imaging and magnetic navigation features of the MRI system, researchers have come up with a large number of magnetic robots which were designed to apply in the human body. However, the existing magnetic robots were either too large for practical use, or small but with limited functionality. In this thesis, a submillimeter-scale, functionalized magnetic robot, named micro-gripper is described. We successfully moved a nickel micro-gripper in an agarose phantom, but the performance was not able to reach our anticipation. Several improvements were hence incorporated in the existing design of micro-grippers. Instead of using nickel, we have used iron as the magnetic layer since iron has almost 2 times higher saturation magnetization than nickel. A geometric optimization of the magnetic layer area on the micro-gripper was carried out and the micro-gripper was redesigned. The micro-gripper was also embedded in a layer of paraffin wax to minimize the friction with the surroundings. With the mobility-enhanced new magnetic micro-gripper, we could successfully accomplish navigation on ex-vivo pig esophagus using gradient magnetic fields in an MRI system