Sequence-Designed Peptide Nanofibers Bridged Conjugation of Graphene Quantum Dots with Graphene Oxide for High Performance Electrochemical Hydrogen Peroxide Biosensor

Motif-designed peptide molecules have the unique property to form filamentous nanostructure and the ability to conjugate with other nanoscale building blocks such as graphene and nanoparticles to create functional nanomaterials. Here, the design of a novel functional peptide molecule is reported, which has the abilities to form peptide nanofibers (PNFs) and recognize with graphene quantum dots (GQDs) and graphene oxide (GO) nanosheet specifically. Based on the design of peptide sequence, the ternary GQD-PNF-GO nanohybrids are synthesized successfully. The created ternary GQD-PNFGO nanohybrids are characterized by transmission electron microscopy and atomic force microscopy (AFM). To understand the formation mechanism of this ternary nanostructure, the interactions between GQD, PNF, and GO are further investigated by AFM-based force spectroscopy. Moreover, it is found that the synthesized ternary GQD-PNF-GO nanohybrids show potential applications for high performance electrochemical hydrogen peroxide (H2O2) biosensor. This fabricated biosensor exhibits high sensitivity and selectivity, low detection limit, and wide linear range for sensing H2O2. It is believed that the strategies shown in this work such as the motif design of peptide and its self-assembly on GO will benefit the further creation of functional binary and ternary nanomaterials, as well as the understanding of their self-assembly and formation mechanisms.