Recently, flagella and cilia have gathered attension since their important role in mammal cells and relation to genetic diseases of human were revealed. Chlamydomonas is one of the model organism of flagella and phototaxis research. The purpose of our research is to track a freely swimming individual Chlamydomonas cell to observe its flagella and whole body movement with dark field microscopy to investigate the phototactic reaction of Chlamydomonas. In this paper, a method for three-dimensional tracking of Chlamydomonas using high-speed visual feedback in dark field microscopy is proposed. The method was implemented to an existing microscope tracking system. It demonstrated successful three-dimensional tracking of a swimimng Chlamydomonas for several tens of seconds. The precisions of the 3D position measurement were estimated as ±1[μm] (XY) and ±10[μm] (Z).
