A molecular assembly that crawls on a solid substrate with a metabolic-like processElectronic supplementary information (ESI) available: Fluorescence confocal microscopy images of vesicles; tabulated dynamic aggregate behaviors; movies of the molecular assemblies, crawling motion of the vesicular aggregates, absorption of smaller vesicles, and film formation. See DOI: 10.1039/c5me00012b

A vesicular aggregate filled with lipid molecules exhibited crawling motion over a glass surface as a result of chemical reactions. The vesicular aggregate was composed of didodecyldimethylammonium bromide (DDAB) and sodium oleate with calcium ions. The crawling motion was induced by the chemical reaction between DDAB and iodide ions, and it caused discharge of the inner lipids. This was responsible for the size reduction of the aggregate. However, it engulfed the neighboring smaller vesicles, which were taken up into the vesicular aggregate in the dehydrated state and became a constituent of the aggregate. The size of the vesicular aggregate recovered and could translate in a sustainable manner. This is probably the first example of an amphiphilic molecular assembly that exhibits crawling motion as a result of chemical reactions without size reduction. This may be regarded as the cell-like behavior of an abiotic molecular assembly with a metabolic-like process. An abiotic amphiphilic aggregate crawls on a solid substrate, engulfing the surrounding smaller vesicles and discharging film-like waste.