Fig. 5: Growth of active droplets.

a Radius traces of all droplets in a selected active droplet experiment (original: video 6). In the inset, the curves were shifted horizontally for better visualization of common behaviour. b Stepwise addition of fuel (PEP) to active droplets. In each step, 1 mM of PEP was added, after the growth curve plateau was reached. Original videos: 9, 10, and 11, respectively. Source videos are provided in Supplementary Data 1. A complete overview of experimental conditions and sample size can be found in Supplementary Table 1. c Profile of the ATP conversion based on average droplet volume evolution (calculated from the dataset in (a)), compared to the profile estimated based on Michaelis–Menten kinetics in solution, using k₂ of 0.3 min⁻¹ and ADP starting concentration of 3 mM. The solid lines are power-law fits to the initial 60 seconds of growth (R² > 0.9, outliers not included). The calculated conversions have been normalized such that the initial slopes cross at (1,1). Note that the ATP conversion in growing droplets and solution cannot be compared directly, since the exact droplet volume fraction is not known.