Visible Light-Controlled Intracellular Synthesis of Supramolecular Peptide Nanostructures

The complex dynamics and transience of supramolecular pathways in living cellular environments impede the correlation between diverse hierarchical species and their biological functions. The necessary breakthrough requires the precise control of supramolecular events at discrete time points via synthetic chemistry and their real-time visualization in native cells. Herein, we designed two peptide sequences that undergo a cascade of visible light-induced molecular and supramolecular transformations to form various assembly species in cells. In contrast to endogenous stimulus-responsive self-assembling systems, the irradiation with light enable full control over the reaction cascade where the monomer generation and concentration in turn regulates the assembly kinetics. Phasor-fluorescence lifetime imaging (phasor-FLIM) traced the formation of various assembly states in cells and revealed subsequent out-of-equilibrium dynamics associated with monomer activation and consumption. These temporally resolved assemblies show that the emergence of cytotoxicity is correlated to the accumulation of oligomers beyond the cellular efflux threshold.