Mimicking Pathogenic Invasion with the Complexes of Au22(SG)18-Engineered Assemblies and Folic Acid.

Biological systems provide the richest spectrum of sophisticated design for materials engineering. We herein provide a paradigm of Au22(SG)18-engineered (SG, glutathione thiolate) and hydrogen bonds engaged assemblies for mimicking capsid protein self-assembly. The water-evaporation-induced self-assembly method allows discrete ultrasmall gold nanoclusters (GNCs) to be self-assembled into super-GNCs assemblies (SGNCs) ranging from nano-, meso- to microscale in water-dimethyl sulfoxide binary solvents in a template-free manner. After removing free and hydration layer water molecules, the formation of SGNCs is engaged by the collective cohesion of hydrogen bonds between glutathione ligands of gradually approaching GNCs. Then, a series of tightly orchestrated cellular events induced by the complexes of Au22(SG)18-engineered assemblies and folic acid are demonstrated to mimic the invasion of eukaryotic cells by pathogens. First, the activation of macropinocytosis mimics the macropinocytic entry used by the pathogens to invade host cells. Then the cytoplasmic vacuolization is a mimicry of vacuolating effects induced by the oligomeric vacuolating toxins secreted by some bacteria. Lastly, the escaping from macropinosomes into cytosol is in a vacuolating toxin's strategy. The findings demonstrate the capabilities of artificial pathogens to emulate the structures and functions of natural pathogens.