Swimming Behavior Analysis Based on Bacterial Chemotaxis in Solution

Microrobots is playing more and more important roles for medical applications, such as targeting tumoral lesions for therapeutic purposes, Minimally Invasive Surgery (MIS) and highly localized drug delivery. However, energy efficient propulsion system poses significant challenges for the implementation of such mobile robots. Flagellated chemotactic bacteria can be used as an effective integrated propulsion system for microrobots. In this paper, we proposed a new type of propulsion method that is inspired by the motility mechanism of flagellated chemotactic bacteria in different pH gradients. The pH gradient field was established in solution through electrolysis method. The distribution of the pH values in solution was measured with pH indicator and analyzed with image processing technology, and the mechanism by which the pH values changed was also discussed. The swimming speed and direction of the bacteria were studied experimentally. Through analyzing the key parameters, such as stabilization time and electrode voltage, the optimal design of propulsion mechanism based on bacteria motion in the pH gradient field was proven.