Surfaces that resist nonspecific protein adsorption in a complex biological milieu are required for a variety of applications. However, few strategies can achieve a robust antifouling coating on a surface in an easy and reliable way, regardless of material type, morphology, and shape. Herein, the preparation of an antifouling coating by one‐step aqueous supramolecular assembly of bovine serum albumin (BSA) is reported. Based on fast amyloid‐like protein aggregation through the rapid reduction of the intramolecular disulfide bonds of BSA by tris(2‐carboxyethyl)phosphine, a dense proteinaceous nanofilm with controllable thickness (≈130 nm) can be covered on virtually arbitrary material surfaces in tens of minutes by a simple dipping or spraying. The nanofilm shows strong stability and adhesion with the underlying substrate, exhibiting excellent resistance to the nonspecific adsorption of a broad‐spectrum of contaminants including proteins, serum, cell lysate, cells, and microbes, etc. In vitro and in vivo experiments show that the nanofilm can prevent the adhesion of microorganisms and the formation of biofilm. Compared with native BSA, the proteinaceous nanofilm coating exposes a variety of functional groups on the surface, which have more‐stable adhesion with the surface and can maintain the antifouling in harsh conditions including under ultrasound, surfactants, organic solvents, and enzymatic digestion.

PEI)-assisted crosslinking with catechol moieties, which could further be used as a Janus platform to support the reduction and attachment of silver nanoparticles on the film surface. [7] Freestanding organicmetal 2D films have potential in many application fields, such as in sensing, surface-enhanced Raman scattering, catalytic reaction, near-infrared photothermal therapy, and biomedical areas. [8][9][10][11] Unfortunately, such films are fabricated via multiple, time-consuming steps; [11,12] in addition, the sacrifice of metal conductivity greatly limits the applications of these materials in the electrical device field. [2,13] Herein, we report a facile, environmentally friendly and bio-based redox system to merge metal nanoparticles under ambient conditions in an aqueous solution via protein bonding, which is distinctive from traditional welding of nanomaterials at high temperatures/ pressures. We discover that the silver nanoparticles from the in situ reduction of silver ammonium ions by glucose were bound by ultrathin amyloid-like β-sheet stacking of lysozyme to create a freestanding large-area (e.g., 400 cm 2 ) 2D silver film at the air/water interface with a purity up to 98%. We prove the great ability of this reaction system toward controlled synthesis of highly reflective and highly conductive silver films with elongation nearly 10 times higher than that of pure metal without protein bonding. These characteristics allow the protein-bound silver films to crucially participate in realistic applications, such as in strain/pressure sensors and artificial throats with ultrasensitive capability for stealth transmission of Morse code via the detection of minute finger tapping and for silent speech recording via the detection of tiny vibrations of the human throat, a result never reported before. No special equipment is necessary for this one-step method, and we further demonstrate that the bonding function of lysozyme is general to other proteins (e.g., albumin, α-amylase, collagen, keratin, and pepsin) and other metal films besides Ag (e.g., Au and Cu) are synthesized easily by this strategy.The protein assembler lysozyme, generally recognized as a safe material by the US Food and Drug Administration, is commercially available at low cost from egg white, body fluids of animals and plant cells. [14] Figure 1a schematically illustrates the synthetic procedures of a lysozyme-bound silver film. Lysozyme from egg white, Tollen's reagent, and d-glucoseThe welding and sintering of nanomaterials is usually achieved at high temperatures and high pressures. Here, it is found that merging of metal nanoparticles occurs under ambient conditions in an aqueous solution via protein bonding. It is discovered that the silver nanoparticles from the in situ reduction of silver ammonium ions by glucose undergo confined nucleation and growth and are bound by ultrathin amyloid-like β-sheet stacking of lysozyme. This merging of silver nanoparticles creates a freestanding large-area (e.g., 400 cm 2 ) 2D silver film at the air/water i...

The design and scalable synthesis of robust 2D biological ultrathin films with a tunable structure and function and the ability to be easily transferred to a range of substrates remain key challenges in chemistry and materials science. Herein, we report the use of the thiol–disulfide exchange reaction in the synthesis of a macroscopic 2D ultrathin proteinaceous film with the potential for large‐scale fabrication and on‐demand encapsulation/release of functional molecules. The reaction between the Cys6–Cys127 disulfide bond of lysozyme and cysteine is chemo‐ and site‐selective. The partially unfolded lysozyme–cysteine monomers aggregate at the air/water or solid/liquid interface to form an ultra‐large 2D nanofilm (900 cm2) with about 100 % optical transparency. This material adheres to a wide range of substrates and encapsulates and releases a range of molecules without significantly affecting activity.

With the development of nanotechnology, functional amyloid materials are drawing increasing attention, and numerous remarkable applications are emerging. Amyloids, defined as a class of supramolecular assemblies of misfolded proteins or peptides into β-sheet fibrils, have evolved in many new respects and offer abundant chemical/biological functions. These proteinaceous micro/nano-structures provide excellent biocompatibility, rich phase behaviours, strong mechanical properties, and stability at interfaces not only in nature but also in functional materials, displaying versatile interactions with surfaces/interfaces that have been widely adopted in bioadhesion, synthetic biology, and composites. Overall, functional amyloids at surfaces/interfaces have excellent potential applications in next-generation biotechnology and biomaterials.