Date Published: January 04, 2018
Publisher: John Wiley and Sons Inc.
Author(s): Xiang Hao, Liang Chen, Wei Sang, Qiang Yan.
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.
Energy dissipation, as one of the most inherent attribute of living systems, underpins biologically dynamic and periodic behaviors.1 For example, biological cells use the chemical fuel, adenosine‐5’‐triphosphate (ATP), to dynamically regulate cell activity and viability;2 microtubules sustain their switchable lengthening/shortening by consuming the energy from guanosine triphosphate.3, 4 These naturally occurring dissipative systems have been known very early; however, in vitro mimicking such “living” systems with adaptive features using “nonliving” molecular building blocks is still a fundamental challenge in chemistry.5, 6
In conclusion, we develop a self‐pulsating vesicular system for the first time that can dissipate chemical energy to maintain their periodic membrane movement in out‐of‐equilibrium state. The transient supramolecular cycle established between ATP and the polymer membrane becomes a driving force to realize the vesicular dynamic evolution. ATP, as a continuous source of chemical fuel, can fine regulate the critical parameters of vesicle pulsation including pulsating periodicity, pulsating amplitude, and operating lifetime. This ATP‐fuelled dissipative self‐assembly pathway represents an entirely new strategy to fulfil the goal of biological motion mimics. The dynamic assemblies are promising to apply as high‐performance microseparator for size‐selective nanoparticle sieving through programmed ATP triggers. We anticipate that these self‐pulsating microcapsules will exemplify the new opportunities of the life‐like assemblies using complex artificial molecular system, and provide new visions from time‐independent static self‐assembly toward time‐ordered dynamic self‐assembly with “living” natures, endowing the system with cell mimicry function.
The authors declare no conflict of interest.