Herein, we report the construction of a novel hydrolase model via self-assembly of a synthetic amphiphilic short peptide (Fmoc-FFH-CONH 2 ) 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-CONH 2 with arginine to produce a structurally similar peptide Fmoc-FFR-CONH 2 , 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 multicatalytic 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 peptidebased material has excellent biocompatibility with human cells and is expected to be applied to organisms as a substitute for natural hydrolases.

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 Agcontaining 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 coli DH5 a).

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Magnetic hyperthermia is a promising application of magnetic nanoparticles (MNPs) in cancer therapy. It is important to consider and optimize the parameters that affect heat dissipation, such as particle diameters, structures, and surface coatings. In this study, we measured the magnetic properties of two superparamagnetic nanoparticles under DC and AC magnetic fields. Resovist is approved to be used as a magnetic resonance imaging contrast agent. CMEADM-033-02, with the blood-pooling property and biocompatibility, exhibits high magnetization. The blood-pooling property makes it easier for MNPs to accumulate in tumors and tissue. While preparing samples, we aligned the easy axis of the samples using a DC magnetic field to enhance heat dissipation. We discussed the magnetic property in terms of magnetic relaxation associated with anisotropy energy. We observed that the peak frequency of Néel relaxation was considerably shifted owing to effectively changed anisotropy by the alignment of the easy axis. However, the change in the peak frequency of Néel relaxation could not be directly confirmed. Furthermore, we calculated the intrinsic loss power (ILP) and specific loss power (SLP) for heat dissipation from the areas of AC magnetization curves and estimated the SLP at 1 MHz to compare with the high heating characteristic of ILP that has been reported in a conventional study. We achieved equivalent ILP for heat dissipation as that reported in the study by aligning the easy axis of the MNPs with the blood-pooling property under a therapeutic condition.

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