Emergence of fluorescent aggregates through hierarchical self-assembly

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Chemical Engineering

Background:

• Controlling the growth of functional supramolecular nano-structures in aqueous media is challenging for soft materials development and understanding macromolecule self-organization.
• Existing methods lack precise control over hierarchical self-assembly processes in water.

Purpose of the Study:

• To investigate the hierarchical self-assembly and growth of functional supramolecular nano-structures in aqueous media.
• To identify factors controlling the self-assembly process and explore feedback mechanisms in nano-structure formation.

Main Methods:

• Utilized a non-fluorescent water-soluble tetraphenylethene tetraaldehyde with complementary hydrazide partners.
• Employed a combinatorial screening assay to identify fluorescent aggregates.
• Observed auto-catalytic growth and component selection using a beta-sheet-forming pentapeptide.

Main Results:

• Hierarchical self-assembly involving dynamic covalent self-assembly followed by supramolecular aggregation was identified.
• Fluorescent aggregates emerged from the reaction system.
• External factors (concentration, pH) and internal factors (side-chain nature) controlled the self-assembly outcome.
• Supramolecular self-assembly exhibited component selection and auto-catalytic growth via a feedback loop.

Conclusions:

• The study demonstrates a controlled method for hierarchical self-assembly of functional nano-structures in water.
• Dynamic covalent chemistry coupled with supramolecular aggregation offers a pathway to emergent complexity in soft materials.
• Feedback mechanisms within supramolecular self-assembly play a crucial role in component selection and growth, paving the way for advanced material design.