Despite the relative simplicity of the form, single-cell creatures have developed complex forms for the exploration of the surrounding space, and researchers from the Max Planck Institute of Dynamics and Self-Organization have conducted a series of experiments to reveal the physical mechanisms that shape the strategies of microfilter movement.
In the first experiment, researchers studied how moving microplanes affect each other, and in their experiment, the microscopic drops of oil in soap solution move independently of each other, releasing a small amount of oil.
The same "inversion footprints" that can scare off other micro-organisms, leave bacteria behind, think scientists. Microploves can determine whether or not a different organism has recently been in the same place. This strategy leads to a self-avoiding movement, explains the authors of the work.
Microorganisms are pushed away from the tracks and move in a closed loop away from each other, while the repulsive effect of one pin from the trajectory of the other is determined by the angle of convergence and the time that has elapsed since the first swim.
In another experiment, scientists have shown that small organisms use hydrodynamic interactions with the canal wall in order to move against the current in a narrow canal; this type of movement explains, for example, how pathogenic bacteria move through blood vessels.
In addition, scientists have studied the collective hydrodynamic behaviour of a large number of microfloats, and have found that multiple drops can form clusters that swim like ships on an aircushion, or rise and rotate like small helicopters, and that individual particles cannot move like this.
Researchers believe that various models of movement found in micro-organisms can be used for the design of nanobots and the development of targeted delivery mechanisms.