Rotational dynamics of Bacillus subtilis in an optical trap

Abstract

The swimming of a bacterium in fluids occurs in a low Reynolds number regime. The ability to confine the swimming motion by trapping a bacterium in laser light, can give information on the propulsion coefficients, which are important in explaining the efficiency of swimming of these bacteria. In this work, we report the results of an optically trapped Bacillus subtilis in an optical tweezer and the studies on the rotatory motion of the bacterium. The data is gathered and analysed using video microscopy. The propulsion coefficients of such swimming bacterium are determined through a power spectral analysis of the rotatory motion of the bacterium in the trap.