Applications of bacterial magnets.

Magnetic bacteria migrate along the lines of the earth's magnetic field, and synthesize intracellular particles of magnetite which are aligned in chains and enveloped by a membrane, thus forming biological magnets. Recent progress in techniques for isolating and culturing one strain offers hope for the large-scale production of bacterial magnets. Potential biotechnological and medical applications will exploit the ability to manipulate conjugates or cells incorporating the particles, whose usefulness depends on their small size and membrane coating.