Artificial pheromone effect imposed on real living microalgae cells confined in a microchip with optical feedback system

Abstract

We designed and examined a completely new concept of artificial pheromone to real living cells of microalgae confined in a microchip. We developed an optical feedback system, in which a patterned light was illuminated on the microchip to induce the photophobic response of microalgae (Euglena gracilis, in this study). The light pattern was generated from the traces of swimming cells as to be attractive or repulsive for the cells through photophobic responses of the cells, which in turn acted as artificial pheromone. We demonstrated that the new concept works as designed and that the cell-distribution pattern was self-developed in a time course of hours. The pheromone can be designed as attractive or repulsive, with setting parameters of intensity, accumulation, diffusion, and evaporation of pheromones. The concept of artificial pheromone will contribute to studying spatio-temporal self-organizing phenomenon in nature, as well as educational purpose.