Bacterial flagella assisted propulsion of patterned latex particles: Effect of particle size

Molecular motors are compact, efficient and sophisticated micro-/nanoscale actuators. However, the process of isolating molecular motors from microorganisms has a low yield; moreover, providing the isolated motors with energy as well as controlling them is very challenging. We have previously demonstrated that flagellar motors within the intact cells of Peritrichous bacteria can be used for controlled propulsion of 10 mum polystyrene beads. In pervious experiments, bacteria were randomly attached over the entire surface of the microbeads. In this work, the microbeads are patterned in order to control the location of bacterial attachment and enhance the efficiency of the propulsion and the directionality of the motion. It is shown that patterned beads are significantly more efficient, yielding nearly the same speed as unpatterned beads for half the number of attached bacteria. More importantly the directionality of the motion is improved by approximately 25%. Furthermore, the effect of microbead size on the attachment density and consequently the propulsion force is investigated.