Single-Walled Carbon Nanotubes as Near-Infrared Fluorescent Multiplexed Optical Reporters for Trigger-Induced π-Conjugated Peptide Self-Assembly

Supramolecular peptide assemblies provide versatile, functional material platforms with structures and properties that can be regulated by molecular design and external stimuli. Monitoring their structural evolution is therefore important for tracking trigger-induced reorganization, and thus property changes, during the assembly process. Here, we introduce near-infrared (NIR) fluorescent single-walled carbon nanotube (SWCNT) optical reporters as probes of trigger-induced peptide self-assembly in aqueous environments. We employ the π-conjugated peptide DVV4T, a quaterthiophene (4T)-Asp-Val-Val unit, as a model system that undergoes electrostatically regulated supramolecular reorganization while simultaneously acting as a noncovalent dispersant for SWCNTs. Exposure to distinct chemical triggers induces self-assembly of DVV4T, which incorporates the peptide-SWCNT hybrids into the resulting supramolecular structures. Electron microscopy reveals trigger-specific morphologies, ranging from bundled filaments to extended, interconnected networks of peptide-SWCNTs. These self-assembly transformations produce trigger-specific, chirality-resolved, time-dependent modulations in the SWCNT NIR fluorescence, enabling optical readouts of supramolecular restructuring within the NIR biologically transparent spectral window. Together, these results establish SWCNTs as information-rich optical transducers of stimulus-responsive peptide self-assembly and highlight their potential for tracking dynamic supramolecular reorganization in adaptive functional nanomaterials.