Swimming in synthetic mucus

Microrobots have the potential to provide major break throughs in medical science through in vivo surgery and targeted drug delivery. However, research into applying microrobots inside non-Newtonian mucus environments has been limited. This paper seeks to demonstrate the swimming capabilities of microswimmer robots inside synthetic mucus. Microswimmer robots are composed of ferromagnetic beads linked together in a linear chain. The microswimmer can translate through the fluid medium of interest using rotating magnetic fields. Synthetic mucus was developed using dried mucin from a porcine stomach and mixed with deionized water in varying concentrations. These formulations were then analyzed using a rheometer to understand their rheological properties. Microswimmers were then inserted into these synthetic mucus formulations and were actuated at varying frequencies. The velocities of micro swimmers were extracted using computer vision techniques. Interestingly, microswimmers were able to swim in concentrations of mucin as high as 5%, however, at such a high concentration microswimmer performance was often inconsistent. Often, microswimmers not of the conventional three bead assembly performed much better than traditional three bead swimmers investigated in past research. These results indicate that smaller and less complicated swimmers can be used for in vivo usage.