Multiscale Mass Transport Across Membranes: From Molecular Scale to Nanoscale to Micron Scale

Multiscale mass transport across membranes occurs ubiquitously in biological systems but is difficult to achieve and long-sought-after in abiotic systems. The multiscale transmembrane transport in abiotic systems requires the integration of multiscale transport channels and energy ergodicity, making multiscale mass transport a significant challenge. Herein, emulsion droplets with cell-like confinement are used as the experimental model, and multiscale mass transport is achieved from molecular scale to nanoscale to micron scale, reproducing rudimentary forms of cell-like transport behaviors. By adjustment of the magnetic dipole interactions between adjacent superparamagnetic nanoparticles (MNPs), the assembled structure at the interface of emulsion droplets is successfully modified, which constructs transport channels of various scales at the interface. Simultaneously, the assembly process of MNPs induces self-emulsification, which increases entropy and further reduces Gibbs free energy, ultimately realizing multiscale mass transport that evolves in time visiting all possible microscopic states (energy ergodicity). This work represents the comprehensive identification and realization of a multiscale transmembrane transport in abiotic droplet systems, which offers opportunities for the development of high-order cell-like characteristics in emulsion droplet-based communities, synthetic cells, microrobots, and drug carriers.