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Enhancing the robustness of functional biomacromolecules is a critical challenge in biotechnology, which if addressed would enhance their use in pharmaceuticals, chemical processing and biostorage. Here we report a novel method, inspired by natural biomineralization processes, which provides unprecedented protection of biomacromolecules by encapsulating them within a class of porous materials termed metal-organic frameworks. We show that proteins, enzymes and DNA rapidly induce the formation of protective metal-organic framework coatings under physiological conditions by concentrating the framework building blocks and facilitating crystallization around the biomacromolecules. The resulting biocomposite is stable under conditions that would normally decompose many biological macromolecules. For example, urease and horseradish peroxidase protected within a metal-organic framework shell are found to retain bioactivity after being treated at 80 °C and boiled in dimethylformamide (153 °C), respectively. This rapid, low-cost biomimetic mineralization process gives rise to new possibilities for the exploitation of biomacromolecules. Robust biomacromolecules could be used for a wide range of biotechnological applications. Here the authors report a biomimetic mineralization process, in which biomolecules are encapsulated within metal-organic frameworks, and their stability is subsequently increased without significant bioactivity loss.

Nacre-mimetics hold great promise as mechanical high-performance and functional materials. Here we demonstrate large progress of mechanical and functional properties of self-assembled polymer/nanoclay nacre-mimetics by using synthetic nanoclays with aspect ratios covering three orders in magnitude (25–3,500). We establish comprehensive relationships among structure formation, nanostructuration, deformation mechanisms and mechanical properties as a function of nanoclay aspect ratio, and by tuning the viscoelastic properties of the soft phase via hydration. Highly ordered, large-scale nacre-mimetics are obtained even for low aspect ratio nanoplatelets and show pronounced inelastic deformation with very high toughness, while those formed by ultralarge nanoplatelets exhibit superb stiffness and strength, previously only reachable for highly crosslinked materials. Regarding functionalities, we report formerly impossible glass-like transparency, and excellent gas barrier considerably exceeding earlier nacre-mimetics based on natural nanoclay. Our study enables rational design of future high-performance nacre-mimetic materials and opens avenues for ecofriendly, transparent, self-standing and strong advanced barrier materials. Nacre-mimetics hold great promise as high-performance, functional materials. Here, the authors use synthetic nanoclays and demonstrate tuneable mechanical properties by varying the nanoclay aspect ratio, and suggest a transparent gas barrier application.

An ability to develop sequence-defined synthetic polymers that both mimic lipid amphiphilicity for self-assembly of highly stable membrane-mimetic 2D nanomaterials and exhibit protein-like functionality would revolutionize the development of biomimetic membranes. Here we report the assembly of lipid-like peptoids into highly stable, crystalline, free-standing and self-repairing membrane-mimetic 2D nanomaterials through a facile crystallization process. Both experimental and molecular dynamics simulation results show that peptoids assemble into membranes through an anisotropic formation process. We further demonstrated the use of peptoid membranes as a robust platform to incorporate and pattern functional objects through large side-chain diversity and/or co-crystallization approaches. Similar to lipid membranes, peptoid membranes exhibit changes in thickness upon exposure to external stimuli; they can coat surfaces in single layers and self-repair. We anticipate that this new class of membrane-mimetic 2D nanomaterials will provide a robust matrix for development of biomimetic membranes tailored to specific applications. Biomimetic membranes can be used for various applications such as sensors and separations. Here, Chen et al . report the assembly of lipid-like peptoids into stable and self-repairing 2D membrane nanomaterials that change in thickness when under external stimuli.

Nacre-like composites have been investigated typically in the form of coatings or free-standing sheets. They demonstrated remarkable mechanical properties and are used as ultrastrong materials but macroscale fibres with nacre-like organization can improve mechanical properties even further. The fiber form or nacre can, simplify manufacturing and offer new functional properties unknown yet for other forms of biomimetic materials. Here we demonstrate that nacre-like fibres can be produced by shear-induced self-assembly of nanoplatelets. The synergy between two structural motifs—nanoscale brick-and-mortar stacking of platelets and microscale twisting of the fibres—gives rise to high stretchability (>400%) and gravimetric toughness (640 J g −1 ). These unique mechanical properties originate from the multiscale deformation regime involving solid-state self-organization processes that lead to efficient energy dissipation. Incorporating luminescent CdTe nanowires into these fibres imparts the new property of mechanically tunable circularly polarized luminescence. The nacre-like fibres open a novel technological space for optomechanics of biomimetic composites, while their continuous spinning methodology makes scalable production realistic. The mechanical properties and hierarchical structure of nacre have been widely investigated as a biomimetic template for applications. Here, the authors demonstrate that nacre-like fibres made from nanoplatelets and polymers show exceptional stretchability and toughness.

Many insect species reversibly adhere to surfaces by combining contact splitting (contact formation via fibrillar contact elements) and wet adhesion (supply of liquid secretion via pores in the insects’ feet). Here, we fabricate insect-inspired fibrillar pads for wet adhesion containing continuous pore systems through which liquid is supplied to the contact interfaces. Synergistic interaction of capillarity and humidity-induced pad softening increases the pull-off force and the work of adhesion by two orders of magnitude. This increase and the independence of pull-off force on the applied load are caused by the capillarity-supported formation of solid–solid contact between pad and the surface. Solid–solid contact dominates adhesion at high humidity and capillarity at low humidity. At low humidity, the work of adhesion strongly depends on the amount of liquid deposited on the surface and, therefore, on contact duration. These results may pave the way for the design of insect-inspired adhesive pads. Many insects supply secretion via small tubes or pores to the end of their legs to be able to attach to a surface. Here, inspired by nature, Xue et al. fabricate adhesive pads with porous nanorod structure for oil delivery, which give rise to a 100-fold increase in adhesivity under humid conditions.

Many natural and biomimetic platelet–matrix composites—such as nacre, silk, and clay-polymer—exhibit a remarkable balance of strength, toughness and/or stiffness, which call for a universal measure to quantify this outstanding feature given the structure and material characteristics of the constituents. Analogously, there is an urgent need to quantify the mechanics of emerging electronic and photonic systems such as stacked heterostructures. Here we report the development of a unified framework to construct universal composition–structure–property diagrams that decode the interplay between various geometries and inherent material features in both platelet–matrix composites and stacked heterostructures. We study the effects of elastic and elastic-perfectly plastic matrices, overlap offset ratio and the competing mechanisms of platelet versus matrix failures. Validated by several 3D-printed specimens and a wide range of natural and synthetic materials across scales, the proposed universally valid diagrams have important implications for science-based engineering of numerous platelet–matrix composites and stacked heterostructures. Many layered composites exhibit a remarkable balance of strength, toughness and stiffness. Here, the authors construct a model to explain the synergy of key mechanical properties of layered composites by considering the elastic/plastic properties of the matrix and use 3D-printed samples to validate their predictions.

Silk and silk fibroin, the biomaterial from nature, nowadays are being widely utilized in many cutting-edge micro/nanodevices/systems via advanced micro/nanofabrication techniques. Herein, for the first time to our knowledge, we report aqueous multiphoton lithography of diversiform-regenerated-silk-fibroin-centric inks using noncontact and maskless femtosecond laser direct writing (FsLDW). Initially, silk fibroin was FsLDW-crosslinked into arbitrary two/three-dimensional micro/nanostructures with good elastic properties merely using proper photosensitizers. More interestingly, silk/metal composite micro/nanodevices with multidimension-controllable metal content can be FsLDW-customized through laser-induced simultaneous fibroin oxidation/crosslinking and metal photoreduction using the simplest silk/Ag + or silk/[AuCl 4 ] − aqueous resists. Noticeably, during FsLDW, fibroin functions as biological reductant and matrix, while metal ions act as the oxidant. A FsLDW-fabricated prototyping silk/Ag microelectrode exhibited 10 4 -Ω −1 m −1 -scale adjustable electric conductivity. This work not only provides a powerful development to silk micro/nanoprocessing techniques but also creates a novel way to fabricate multifunctional metal/biomacromolecule complex micro/nanodevices for applications such as micro/nanoscale mechanical and electrical bioengineering and biosystems. Scientists are increasingly realising the potential for natural materials in micro- and nanofabrication. Here, the authors employ silk-based resists for aqueous multiphoton lithography towards generating intricate structures by femtosecond direct writing.

β-Peptoids are peptidomimetics based on N -alkylated β-aminopropionic acid residues (or N -alkyl-β-alanines). This type of peptide mimic has previously been incorporated in biologically active ligands and has been hypothesized to be able to exhibit foldamer properties. Here we show, for the first time, that β-peptoids can be tuned to fold into stable helical structures. We provide high-resolution X-ray crystal structures of homomeric β-peptoid hexamers, which reveal right-handed helical conformations with exactly three residues per turn and a helical pitch of 9.6–9.8 Å between turns. The presence of folded conformations in solution is supported by circular dichroism spectroscopy showing length- and solvent dependency, and molecular dynamics simulations provide further support for a stabilized helical secondary structure in organic solvent. We thus outline a framework for future design of novel biomimetics that display functional groups with high accuracy in three dimensions, which has potential for development of new functional materials. β-Peptoids are based on N -alkylated β-aminopropionic acid residues, which have been inspired by the more intensely studied peptoids and β-peptides. Here, the authors report X-ray crystal structures of oligomeric β-peptoids demonstrating secondary structures with this backbone.

For long-lasting artificial hip joint implants, it is necessary to reduce the wear of the acetabular liner composed of ultra-high-molecular-weight polyethylene (UHMWPE) and to eliminate periprosthetic osteolysis. An articular cartilage-mimicking technology has been developed for nanoscale surface modification by grafting poly(2-methacryloyloxyethyl phosphorylcholine) (MPC) onto a highly cross-linked UHMWPE (X-UHMWPE) using photoinduced polymerization. The thickness of the poly(MPC) graft layer is 100–200 nm. This treatment increases the surface hydrophilicity. Other hydrophilic polymers grafted onto the X-UHMWPE are not suitable for long-term functioning under biological conditions. Studies of the tribological and biological effects with poly(MPC) grafted onto the X-UHMWPE substrate revealed that this grafting decreases the production of wear particles and bone resorption responses. The poly(MPC)-grafted X-UHMWPE has been introduced onto an artificial hip joint as a liner for lubrication. This artificial hip joint has been used clinically since 2011 and has been implanted in more than 20 000 patients. This technology has also been applied to the surface modification of PMPC on poly(ether ether ketone) (PEEK), using self-initiated photoinduced grafting, for the development of a new type of artificial joint. This articular cartilage-mimicking technology, which is applied to obtain highly lubricating surfaces, is therefore suitable for preparing artificial hip joint substrates. For long-lasting implants of an artificial hip joint, it is necessary to reduce the wear of the acetabular liner made with polyethylene (PE). An articular cartilage-mimicking technology has been developed by grafting poly(2-methacryloyloxyethyl phosphorylcholine (MPC)) onto a highly cross-linked PE using photoinduced polymerization. The thickness of the poly(MPC) graft layer is 100–200 nm. The poly(MPC)-grafted PE has been introduced on an artificial hip joint system as a liner for lubrication. This artificial hip joint has been used clinically since 2011 and implanted on over 20 000 patients.

Anthracyclines such as doxorubicin are used extensively in the treatment of cancers. Anthraquinone-related angucyclines also exhibit antiproliferative properties and have been proposed to operate via similar mechanisms, including direct genome targeting. Here, we report the chemical synthesis of marmycin A and the study of its cellular activity. The aromatic core was constructed by means of a one-pot multistep reaction comprising a regioselective Diels–Alder cycloaddition, and the complex sugar backbone was introduced through a copper-catalysed Ullmann cross-coupling, followed by a challenging Friedel–Crafts cyclization. Remarkably, fluorescence microscopy revealed that marmycin A does not target the nucleus but instead accumulates in lysosomes, thereby promoting cell death independently of genome targeting. Furthermore, a synthetic dimer of marmycin A and the lysosome-targeting agent artesunate exhibited a synergistic activity against the invasive MDA-MB-231 cancer cell line. These findings shed light on the elusive pathways through which anthraquinone derivatives act in cells, pointing towards unanticipated biological and therapeutic applications. Marmycin A is an anthraquinone natural product with antiproliferative properties. Now the chemical synthesis of marmycin A—through a Diels–Alder cycloaddition, an Ullmann aromatic amination and a Friedel–Crafts cyclization—has enabled a study of its biological activity. Fluorescence microscopy reveals that marmycin A accumulates in lysosomes and promotes cell death independently of genome targeting.