Amyloid-Inspired Peptide Hydrogels for In Situ Formation of Catalytic Nanoparticles: Implications for Environmental Remediation

Despite being intrinsically associated with pathological conditions, proteinaceous amyloid-like structures have recently been realized in engineering hybrid functional materials with versatile utilities. Remarkably, amyloid-like fiber formation, not only limited to full-length proteins, also emerges in short peptides, offering a facile and modular pathway to develop hybrid nanoarchitectures. Orchestrating nanostructured hybrid materials through a bottom-up approach utilizing robust bioinspired platforms presents a powerful strategy for advancing functional nanotechnologies. In a quest to integrate the structural order and robustness of amyloid-like fibers with the functional diversity of nanomaterials, we employed an amyloid-inspired dipeptide hydrogel that simultaneously serves as a reducing agent and a structural template, enabling the in situ synthesis and spatial confinement of monometallic (Au) and bimetallic (AgAu) nanoparticles. The 3D fibrillar network of the hydrogel enables the formation of well-dispersed, stabilized nanoparticles, without the need for external reducing agents or surfactants. The favorable spatial organization of the Au nanoparticles ensures their catalytic potential, as exemplified by the efficacious reduction of environmentally toxic pollutants such as 4-nitrophenol and acetophenone, and the degradation of hazardous synthetic dyes. The peptide hydrogel matrix further allows interfacial catalysis, improving substrate accessibility and catalytic efficiency under aqueous conditions. Moreover, the semisolid nature of the catalytic platform ensures excellent reusability, implying its promising applications in sustainable and cost-effective catalysis. This work exemplifies one of the early demonstrations of bimetallic nanoparticle synthesis within a self-assembled peptide hydrogel framework. Overall, these results demonstrate the potential of amyloid-inspired rudimentary peptide assemblies as robust nanofabrication templates for constructing functional soft-nanomaterial hybrids for efficacious catalytic transformations relevant to environmental remediation.