Swimming characteristics of helical microrobots in fibrous environments

Wireless magnetic microrobots show great potential for targeted drug delivery or as minimally invasive surgical tools in the human body. In order to swim through bodily fluids, such as the vitreous humor in the eye, they must be equipped to successfully move through viscoelastic fluids, where they are obstructed by fibrous networks or microparticles. Prior researchers have shown an increased propulsion efficiency with increasing viscoelastic properties for artificial helical swimmers and bacteria with helical flagella. This work investigates the effect of solutions with increasing collagen concentrations on the propulsion velocity of a magnetically actuated helical microswimmer. Results are in agreement with prior experiments and theory and show a performance peak for a helical microrobot of length 280 μm swimming in a fibrous solution with collagen concentration of 1578 μg/ml.