Stochastic dynamics of bacteria propelled spherical micro-robots

In this work we develop a stochastic dynamic model of bacteria propelled spherical micro-robots. S. marcescens type bacteria attach in small numbers to the surfaces of spherical microbeads. Given a small number of attached bacteria, generally 8-41, collective-behavior stochastic models become not applicable, hence a model based on individual bacterium behavior and motion is developed. This stochastic simulation is used to study the flexibility of the flagellar hook by comparing simulated and experimental results. The effect of bead diameter and the number of attached bacteria is investigated in this manner, with the results favoring a stiffer flagellar hook. The theoretical framework is intended to be used as a simulation and design tool for bacteria propelled micro-robots employed in future medical applications.