Herein, we report the construction of a novel hydrolase model via self-assembly of a synthetic amphiphilic short peptide (Fmoc-FFH-CONH₂) into nanotubes. The peptide-based self-assembled nanotubes (PepNTs-His) with imidazolyl groups as the catalytic centers exhibit high catalytic activity for p-nitrophenyl acetate (PNPA) hydrolysis. By replacement of the histidine of Fmoc-FFH-CONH₂ with arginine to produce a structurally similar peptide Fmoc-FFR-CONH₂, guanidyl groups can be presented in the nanotubes through the co-assembly of these two molecules to stabilize the transition state of the hydrolytic reaction. Therefore significantly improved catalytic activity has been achieved by the reasonable distribution of three dominating catalytic factors: catalytic center, binding site and transition state stabilization to the co-assembled peptide nanotubes (PepNTs-His-Arg_max). The resulting hydrolase model shows typical saturation kinetics behaviour to that of natural enzymes and the catalytic efficiency of a single catalytic center is 519-fold higher than that without catalysts. As for a nanotube with multi-catalytic centers, a remarkable catalytic efficiency could be achieved with the increase of building blocks. This model suggests that the well ordered and dynamic supramolecular structure is an attractive platform to develop new artificial enzymes to enhance the catalytic activity. Besides, this novel peptide-based material has excellent biocompatibility with human cells and is expected to be applied to organisms as a substitute for natural hydrolases.

Recent advances in the preparation of high-performance artificial enzymes based on MIPs and molecularly imprinted nanozymes.

In this work, we employ Fmoc-peptide-based self-assembled nanofibers which are equipped with numerous carboxylic acid and thiol groups on their exterior as scaffolds for the mineralization of silver nanoparticles (Ag-PepNFs). The space- and size-constraint effect along with physical isolation provided by the nano-templates of peptide nanofibers facilitates the production of Ag nanoparticles (AgNPs) with high monodispersity and stability. These Ag-PepNFs nanocomposites can maintain stability for up to 3 months of storage at room temperature in air. In comparison to the traditional Ag-containing materials, Ag-PepNFs nanocomposites offer obvious advantages of ease of fabrication, good biocompatibility, inexpensive production, functional flexibility. More importantly, the tubular nanocomposite are shown to possess a highly effective and long-term antibacterial activity against both Gram-positive bacteria (Bacillus subtilis) and Gram-negative bacteria (Escherichia coliDH5 α).

Size-tunable graphene oxides (GO) were synthesized as a horseradish peroxidase (HRP) mimic for colorimetric detection of organophosphorus pesticides (OPs) at nanomolar levels via a cascade reaction. A GO-based colorimetric method showed high sensitivity and stability toward OPs, which hold great potential in public health applications.