Micromanipulation of biological systems with microelectromagnets

Micromanipulation of biological systems with microelectromagnets, a ring trap, and a matrix, was demonstrated. A ring trap is a circular conducting wire topped with an insulating layer, whereas a matrix consists of two arrays of wires, aligned perpendicular to each other, that are separated and covered with insulating layers. Microelectromagnets can create strong and local magnetic field profiles on micrometer length scales, controlling the motion of magnetic particles and biological systems in a fluid at room temperature. Magnetic beads, yeast cells bound to magnetic beads, and magnetotactic bacteria were trapped with a ring trap; they were continuously moved and assembled with a matrix. With versatile manipulation capabilities, microelectromagnets can be a new tool for biological and medical applications.