Synthetic Active Droplets Inspired by Life

ended

Active droplets are made of molecular building blocks that are activated and deactivated by a chemical reaction cycle. In the activation, a precursor is converted into a building block for droplets driven by the consumption of fuel. In the deactivation, the building blocks react back to the precursor. In other words, active droplets emerge when fuel is supplied, but decay when fuel is depleted. Theoretical studies show active droplets all evolve to the same size. Another work predicts that the droplets can spontaneously self-divide when energy is abundant. All of these exciting properties, i.e., emergence, decay, collective behavior, and self-division are pivotal to the functioning of life. If we could engineer these behaviors in synthetic materials, we would obtain a better understanding of active assembly which is directly relevant to biology and the origin of life. I thus aim to synthesize active droplets and study their life-like properties. Two types of active droplets will be investigated; one type based on oil-molecules that phase separate in water, and one type based on cationic peptides in a complex coacervate with RNA. My team will develop reaction cycles that drive the droplet formation, thereby making them active. We will study their spontaneous emergence in response to energy, and disappearance when energy is scarce. Moreover, we study their collective behavior, like how they grow into one large droplet, or all converge to the same droplet volume. Finally, we test their division into daughter droplets. Our systematic approach will test how kinetic parameters, like the activation rate, affect the behavior of the droplets. The results will mark a massive step forward in the engineering of materials with life-like behaviors, which can also serve as experimental models for membrane-less organelles. We expect to elucidate mechanisms that could have played a role in the origin of life. Finally, our findings could form stepping stones towards a synthetic cel.