Generation of magnetic microswimmers by incorporation of terbium into a microalga
G. Santomauro (Sp), A. V. Singh, M. Mohammadrahimi, E. Goering, G. Schütz, M. Sitti, J. Bill
Living microorganisms are able to take up non-bionic elements and incorporate them through detoxification mechanisms. Here we demonstrate that the microalga Chlamydomonas reinhardtii gains magnetic properties by incorporation of the lanthanide terbium. The unicellular microswimmers were incubated in presence of high amounts of terbium; afterwards the incorporation of the lanthanide into the cell was proven by chemical and fluorescence measurements. We could show by the following SQUID investigations that the cells gained superparamagnetic properties and that the magnetic moment of one magnetized C. reinhardtii cell is 1.6 x 10^-11 emu, which is comparable to the magnetic moment of magnetotactic bacteria. We could achieve magnetic control along two-dimensional trajectories on a rotating magnet. Consequently, we produced magnetic microswimmers by incorporation of terbium. In addition, we tested the biocompatibility of C. reinhardtii and human cells by co-culture. Both cell types showed mutual biocompatibility, indicating that the algae cells are noncytotoxic.