Unexpected fluorescence in peptide amphiphile micelles for molecular-recognition sensing applications

Intrinsically fluorescent soft materials have been widely studied for their signaling applications. A class of fluorescent materials of recent interest are aggregation-induced emission (AIE) materials, which consist of molecules which only fluoresce when assembled into a larger construct. However, the mechanism of AIE is poorly understood, and the materials are often poorly soluble in water, hard to synthesize, and difficult to functionalize, which limits their potential for mechanistic study and real-world impact. Interestingly, I recently discovered that peptide amphiphile (PA) micelles fluoresce without individually fluorescent subunits or aromatic rings, revealing a new class of AIE materials not previously studied. Peptide amphiphiles consist of a functional peptide headgroup conjugated to a hydrophobic tail that spontaneously self-assemble in water. They are water-soluble and easy to straightforwardly functionalize using well-controlled sequence-specific synthesis. Moreover, preliminary results indicate that fluorescence is quenched when the PA micelles bind to phosphate, presenting a promising and readily tunable platform for mechanistic study and sensing applications. This work will present the design, characterization, and functionality of this newly discovered and versatile AIE material.