Magnetic Helical Microswimmers Made by Spirulina through Electroless Nickel Plating

We present a simple technique to fabricate magnetic helical microswimmers with excellent surface quality and swimming performance. These were obtained through depositing a nickel film on the Spirulina biotemplates by electroless nickel plating. The morphology and coating composition of the as-prepared microswimmers were analyzed. Homogeneous and compact nickel coating was successfully deposited on the helical biotemplates, and Ni element could reach similar to 95wt%. Its magnetic property was also characterized. Moreover, a controlled rotating magnetic field was applied to manipulate such a microswimmer in deionized water. Its motion behavior was further analyzed, indicating that such microswimmers could be actuated and steered precisely at low Reynolds numbers. The magnetic helical microswimmers may have potential biomedical applications such as targeted drug delivery and cell manipulation.