Toward Self-Propelled Microrobots: A Systems Chemistry that Induces Non-Linear Phenomena of Oil Droplets in Surfactant Solution

Biological activities observed in living systems occur as the output of which nanometer-, submicrometer-, and micrometer-sized structures and tissues non-linearly and dynamically behave through chemical reaction networks, including the generation of various molecules and their assembly and disassembly. To understand the essence of the dynamic behavior in living systems, simpler artificial objects that exhibit cell-like non-linear phenomena have been recently constructed. However, most objects exhibiting cell-like dynamics have been found through trial-and-error experiments, and there are no strategies for designing them as molecular systems. This review describes how cell-like dynamics of oil droplets in surfactant solution, such as self-propelled motion, chemotaxis, division, and deformation, are induced by combining molecular properties of system components toward self-propelled microrobots.