Amyloid-Like Assembly to Form Film at Interfaces: Structural Transformation and Application

Blacking any Material Surface by Amyloid-Fortified Carbon Coating Toward High-Performance Large-Scale Solar Steam Generation System

Enhancing the interfacial adhesion between carbon-based coatings and substrates through a simple method remains a challenge, mainly due to the intrinsic chemical inertness of carbon materials. Herein, a carbon nanosphere-based coating utilizing an amyloid-like protein aggregation strategy is developed, involving only the reaction of protein, reductant, and carbon nanospheres in an aqueous solution at room temperature. The resultant coating, enriched in amyloid-like protein structures, features both robust interfacial adhesion and high light absorption (≈98.5%) covering the entire UV/Vis to NIR regions. Adhesion energy between the coating and the glass exceeds 5436 J m-2, which is at least five times higher than those polymer-reinforced carbon-based coatings. Combining the strong adhesion and excellent photothermal conversion performance of this coating, a solar steam generation system is constructed with a water treatment capacity of 13.01 kg m-2 d-1, which is sufficient to provide daily supply for tens of people. Importantly, the photothermal conversion unit can be repeatedly cleaned and rolled up for storage, which is beneficial for the construction of portable devices. This work provides a facile and valuable method for preparing carbon-based coatings with strong interfacial adhesion, exhibiting great promise in energy conversion and storage, flexible wearable sensors, photothermal therapy, and so on.

Interfacially Self-Assembled Mutifunctional Protein Thin Films for Accelerated Wound Healing

The design of mutifunctional protein films for large-area spatially ordered arrays of functional components holds great promise in the field of biomedical applications. Herein, interfacial electrostatic self-assembly was employed to construct a large-scale protein thin film by inducing electrostatic interactions between three bovine serum albumin (BSA)-coated nanoclusters and cetyltrimethylammonium bromide (CTAB), leading to their spontaneous organization and uniform distribution at the oil-water interface. This protein film demonstrated excellent multienzyme functions, high antibacterial activity, and pH-responsive drug release capability. Therefore, it can accelerate the wound closure process through a synergistic effect that includes reducing local blood glucose levels, regulating cellular oxidative stress, eradicating bacteria, and promoting cell proliferation.

Structure of Amyloid Peptide Ribbons Characterized by Electron Microscopy, Atomic Force Microscopy, and Solid-State Nuclear Magnetic Resonance

Polypeptides often self-assemble to form amyloid fibrils, which contain cross-β structural motifs and are typically 5-15 nm in width and micrometers in length. In many cases, short segments of longer amyloid-forming protein or peptide sequences also form cross-β assemblies but with distinctive ribbon-like morphologies that are characterized by a well-defined thickness (on the order of 5 nm) in one lateral dimension and a variable width (typically 10-100 nm) in the other. Here, we use a novel combination of data from solid-state nuclear magnetic resonance (ssNMR), dark-field transmission electron microscopy (TEM), atomic force microscopy (AFM), and cryogenic electron microscopy (cryoEM) to investigate the structures within amyloid ribbons formed by residues 14-23 and residues 11-25 of the Alzheimer's disease-associated amyloid-β peptide (Aβ14-23 and Aβ11-25). The ssNMR data indicate antiparallel β-sheets with specific registries of intermolecular hydrogen bonds. Mass-per-area values are derived from dark-field TEM data. The ribbon thickness is determined from AFM images. For Aβ14-23 ribbons, averaged cryoEM images show a periodic spacing of β-sheets. The combined data support structures in which the amyloid ribbon growth direction is the direction of intermolecular hydrogen bonds between β-strands, the ribbon thickness corresponds to the width of one β-sheet (i.e., approximately the length of one molecule), and the variable ribbon width is a variable multiple of the thickness of one β-sheet (i.e., a multiple of the repeat distance in a stack of β-sheets). This architecture for a cross-β assembly may generally exist within amyloid ribbons.