Bacteria-inspired magnetic polymer composite microrobots

Remote-controlled swimming microrobots are promising tools for future biomedical applications. Magnetically actuated helical microrobots that mimic the propulsion mechanism of E. coli bacteria are one example, and presented here is a novel method to fabricate such microrobots. They consist of a polymer-nanoparticle composite, which is patterned using a direct laser writing tool. The iron-oxide nanoparticles respond to the externally applied low-strength rotating magnetic field, which is used for the actuation of the microrobots. It is shown that a helical filament can be rotated around its axis without the addition of a body part and without structuring the magnetization direction of the composite. The influence of the helicity angle on the swim behavior of the microrobots is examined and experimental results show that a small helicity angle of 20 degrees is preferred for weakly magnetized microstructures.