Harnessing theInterface of Water Microdroplets toAccelerate Energy Substance Adenosine Triphosphate Formation

Adenosine triphosphate (ATP) as an energy source plays a key role in providing and regulating energy for life activities in all organisms. Abiotic synthesis of ATP in vitro remains a challenge due to thermodynamic and kinetic constraints in water bulk solution. Here, we report that adenosine diphosphate (ADP) in the presence of potassium phosphate (K₃PO₄) spontaneously generates ATP in water microdroplets under ambient conditions and without catalysts. Dependence of conversion rate on microdroplet size and concentration was determined, which indicated phosphorylation of ADP to ATP occurred at or near the surface of the microdroplets. A weakly acidic environment and a certain concentration of metal ions favored the phosphorylation reaction in the microdroplets. Our results suggest that microdroplets with an energetically favorable microenvironment will be an avenue rich in opportunities for abiotic synthesis of biologically active compounds in the prebiotic era and enzyme-free synthesis.