Functionalization of Magnetotactic Bacteria for Microrobotic Applications

Due to their ability of point-to-point positioning, magnetotactic bacteria (MTB) have widely attracted interest in different kinds of fields like drug delivery, medical diagnosis, and transport of micrometer-sized loads. MTB possess flagella and can swim along magnetic field lines due to chains of magnetosomes in their bodies. There have been attempts to load particles and drugs on MTB using antigen-antibody and some chemical reactions. However, the processes reported to date are complicated and time consuming. Here, we demonstrated a simple procedure to attach nanometer-sized superparamagnetic particles onto the surfaces of MTB to manipulate the spatial position of MTB using external magnetic fields. Nanoparticles were immobilized onto the surfaces of the MTB by putting them into a solution containing magnetic nanoparticles terminated with carboxyl groups and water-soluble 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride. After immobilization, we were able to control the movement of MTB immobilized with nanoparticles.