Periodically Self-Pulsating Microcapsule as Programmed Microseparator via ATP-Regulated Energy Dissipation.

Living systems can experience time-dependent dynamic self-assembly for periodic, adaptive behavior via energy dissipation pathway. Creating in vitro mimics is a daunting mission. Here a "living" giant vesicle system that can perform a periodic pulsating motion using adenosine-5'-triphosphate (ATP)-fuelled dissipative self-assembly is described. This dynamic system is built on transient supramolecular interactions between the polymer and cellular energy currency ATP. The vesicles capturing ATPs will deviate away from equilibrium, leading to an energy ascent that drives a continuous vesicular expansion, until a competitive ATP hydrolysis predominates to break the ATP-polymer interactions and deplete the energy stored in the vesicles, leading to an opposing vesicular contraction. The input of ATP energy can sustain that these vesicles run periodically along this reciprocating expansile-contractile process, resembling a "pulsating" behavior. ATP level can orchestrate the rhythm, amplitude, and lifetime of this biomimetic pulsation. By pre-programming the ATP stimulation protocol, this kind of adaptive microcapsules can function as high-performance microseparators to perform size-selective sieving of different nanoparticles through ATP-mediated transmembrane traffic. This man-made system offers a primitive model of time-dependent dynamic self-assembly and may offer new ways to build life-like materials with biomimetic functions.