There is an increasing interest in synthetic systems that can execute bioinspired chemical reactions without requiring the complex structures that characterize enzymes in their components. The hierarchical self-assembly of peptides provides a means to create catalytic microenvironments. Ideally, as it occurs in enzymes, the catalytic activity of peptide nanostructures should be reversibly regulated. In a typical enzyme mimetic design, the peptide’s self-assembling and catalytic activities are segregated into different regions of the sequence.
Here, we aimed to design minimal peptides in which the self-assembly and function were all encoded in the same amino acids. Moreover, we wanted to endow the resulting one-component nanomaterial with divergent, chemically unrelated, catalytic activities, a property not observed in natural enzymes. We show that short peptides consisting only of histidine and tyrosine residues, arranged in a binary pattern, form biocompatible amyloid-like fibrils and hydrogels combining hydrolytic and electrocatalytic activities. The nanofibers’ mesoscopic properties are controlled by pH, the transition between assembled active β-sheet fibrils, and disassembled inactive random coil species occurring in a physiologically relevant pH range. The structure of one of such amyloid-like fibrils, as derived from molecular dynamic simulations, provides insights on how they attain this combination of structural and catalytic properties.
Sustainable energy conversion & storage systems
pH-Responsive Self-Assembly of Amyloid Fibrils for Dual Hydrolase-Oxidase Reactions
Marta Díaz-Caballero, Susanna Navarro, Miquel Nuez-Martínez, Francesca Peccati, Luis Rodríguez-Santiago, Mariona Sodupe, Francesc Teixidor, and Salvador Ventura*
The development of high energy density battery technologies based on divalent metals as the negative electrode is very appealing. Ca and Mg are especially interesting choices due to their combination of low standard reduction potential and natural abundance.
Interfacial thermal transport plays a prominent role in the thermal management of nanoscale objects and is of fundamental importance for basic research and nanodevices. At metal/insulator interfaces, a configuration commonly found in electronic devices, heat transport strongly depends upon the effective energy transfer from thermalized electrons in the metal to the phonons in the insulator.
The global energy demand continues to grow both due to the increasing population and wealth. As one of the potential solutions, renewable energy resources can relieve the pressure on conventional energy sources. However, due to fluctuations in both supply and demand, they need to be complemented with load-leveling technologies.
We present a method to dissolve carbon nanotubes that simultaneously allows to prepare n-doped films. These films are composed of thinner bundles of longer tubes when compared to films prepared using surfactants and sonication.
Conspectus Over the past 30 years, the engineering of plasmonic resonances at the nanoscale has progressed dramatically, with important contributions in a variety of different fields, including chemistry, physics, biology, engineering, and medicine. However, heavy optical losses related to the use of noble metals for the fabrication of plasmonic structures hindered their application in various settings.