Emergence of fluorescent aggregates through hierarchical self-assembly.

Controlling the growth of functional supramolecular nano-structures in aqueous media is a current challenge both for developing soft materials and for understanding the emergence of complex macromolecules by self-organization. We investigated here the growth of systems combining a non-fluorescent water-soluble tetraphenylethene tetraaldehyde with complementary hydrazide partners, and found that fluorescent aggregates, identified through a combinatorial screening assay, emerge through a hierarchical self-assembly involving dynamic covalent self-assembly followed by supramolecular aggregation. The process is controlled, on one hand, by external (concentration, pH) and internal (nature of side-chain) factors which dictates the outcome of the self-assembly, while, on the other hand, the supramolecular self-assembly exerts, through a feed-back loop, component selection and auto-catalytic growth which was observed using a β-sheet-forming pentapeptide.