Self-assembling peptides act as versatile templates for gold nanoparticle (AuNP) synthesis. Their organization into discrete nanostructures or hydrogels enables control over AuNP morphology and assembly, offering new opportunities for functional nanomaterials.

Peptide-based supramolecular assemblies have emerged as useful scaffolds to control the synthesis and spatial organization of gold nanoparticles (AuNPs) into nanocomposite superstructures. This concept article summarizes recent progress in the design of peptide-directed AuNP assemblies, focusing on how subtle variations in peptide sequence, conjugation strategy, and synthesis conditions influence NP morphology, chiral arrangement, and the resulting optical properties. It highlights key strategies for rationally tailoring structural parameters, such as particle size, shape, and interparticle spacing, which determine the collective optical and plasmonic behaviors of the assemblies. The fundamental design rules discussed here provide critical insights for constructing programmable AuNP-based nanomaterials, potentially useful in diverse fields including sensing, optical devices, and catalysis. Finally, it outlines current challenges and propose directions to further exploit the unique versatility of peptide-nanoparticle hybrid systems in nanotechnology.