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 discovery of novel high-performing materials such as non-fullerene acceptors and low band gap donor polymers underlines the steady increase of record efficiencies in organic solar cells witnessed during the past years. Nowadays, the resulting catalogue of organic photovoltaic materials is becoming unaffordably vast to be evaluated following classical experimentation methodologies: their requirements in terms of human workforce time and resources are prohibitively high, which slows momentum to the evolution of the organic photovoltaic technology.
Major research efforts are being carried out for the technological advancement to an energetically sustainable society. However, for the full commercial integration of electrochemical energy storage devices, not only materials with higher performance should be designed and manufactured but also more competitive production techniques need to be developed.
Recently synthesized hexagonal group IV materials are a promising platform to realize efficient light emission that is closely integrated with electronics. A high crystal quality is essential to assess the intrinsic electronic and optical properties of these materials unaffected by structural defects. Here, we identify a previously unknown partial planar defect in materials with a type I3 basal stacking fault and investigate its structural and electronic properties.
The advanced materials industry is one of the leading technology sectors worldwide. The development of such materials is at the core of the technological innovations and has been possible in the last century thanks to the transition from “observational” science to “control” science.
Transition metal carbides have gathered increasing attention in energy and electrochemistry applications, mainly due to their high structural and physicochemical properties. Their high refractory properties have made them an ideal candidate coating technology and more recently their electronic similarity to the platinum group has expanded their use to energy and catalysis. Here, we demonstrate that the nanostructuring and stoichiometry control of the highest melting point material to this date (Ta-Hf-C) results in outstanding electrochemical stability.