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Abstract Signaling pathways in fungi offer a profound avenue for harnessing cellular communication and have garnered considerable interest in biomaterial engineering. Fungi respond to environmental stimuli through intricate signaling networks involving biochemical and electrical pathways, yet deciphering these mechanisms remains a challenge. In this review, an overview of fungal biology and their signaling pathways is provided, which can be activated in response to external stimuli and direct fungal growth and orientation. By examining the hyphal structure and the pathways involved in fungal signaling, the current state of recording fungal electrophysiological signals as well as the landscape of fungal biomaterials is explored. Innovative applications are highlighted, from sustainable materials to biomonitoring systems, and an outlook on the future of harnessing fungi signaling in living composites is provided.

Abstract Carbons form critical components in biogas purification and energy storage systems and are used to modify polymer matrices. The environmental impact of producing carbons has driven research interest in biomass‐derived carbons, although these have yield, processing, and resource competition limitations. Naturally formed fungal filaments are investigated, which are abundantly available as food‐ and biotechnology‐industry by‐products and wastes as cost‐effective and sustainable templates for carbon networks. Pyrolyzed Agaricus bisporus and Pleurotus eryngii filament networks are mesoporous and microscale with a size regime close to carbon fibers. Their BET surface areas of ≈282 m2 g−1 and ≈60 m2 g−1, respectively, greatly exceed values associated with carbon fibers and non‐activated pyrolyzed bacterial cellulose and approximately on par with values for carbon black and CNTs in addition to pyrolyzed pinewood, rice husk, corn stover or olive mill waste. They also exhibit greater specific capacitance than both non‐activated and activated pyrolyzed bacterial cellulose in addition to YP‐50F (coconut shell based) commercial carbons. The high surface area and specific capacitance of fungal carbon coupled with the potential to tune these properties through species‐ and growth‐environment‐associated differences in network and filament morphology and inclusion of inorganic material through biomineralization makes them potentially useful in creating supercapacitors.

Abstract Poly(ether ketone ketone) (PEKK) is a semicrystalline high‐performance polymer with exceptional mechanical properties, high continuous operation temperature, and is insoluble in most common solvents. Porous PEKK, desired for biomedical applications, is produced by a high‐temperature thermally induced phase separation process using PEKK solutions in two high boiling aprotic solvents, 4‐phenylphenol and 9‐fluorenone, with concentrations up to 20 wt.%. It is demonstrated that the solvent choice has a pronounced influence on the phase separation behavior, which determines the foam morphology, physical and mechanical properties of PEKK foams. Porous PEKK with porosities ranging from 70% to 90%, specific surface areas up to 194 m2 g−1 and elastic moduli ranging from 35 to 100 MPa are produced.

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Macroporous polymers and nanocomposites remain popular materials due to their low densities and unique interconnected pore structures. The determination of mechanical properties in relevant loading conditions, such as shear, remains largely underexplored due to the comparative complexity of such analysis compared to simple compression tests. We investigated the use of the Arcan test to induce uniform biaxial stress in such materials and provide insight into the effect of porosity and silica particle reinforcement on shear properties and fracture toughness of high/medium internal phase emulsion templated macroporous polymer nanocomposites, called polyHIPE/MIPEs. Increasing foam densities were associated with greatly improved tensile and shear properties. Improvements in shear strength and modulus were also noted in polyMIPEs reinforced with as little as 5 wt.% silica nanoparticles, although any increase in tensile properties was lacking. Fracture toughness was investigated using an assumed Poisson's ratio. Decreasing the porosity of macroporous polymers and increasing particle loading resulted in considerable improvements in fracture toughness. These results illustrated the potential of the Arcan test as a simple and effective method for investigating otherwise rarely reported loading conditions in macroporous polymers and nanocomposites.

Volumetric N2 adsorption at −196°C is generally accepted as “gold standard” for estimating the Brunauer-Emmet-Teller (BET) surface area of nanocellulose. It is unclear however, whether the BET surface area of nanocellulose obtained at such low temperatures and pressures is meaningful at an absolute sense, as nanocellulose is used at ambient temperature and pressure. In this work, a systematic evaluation of the BET surface area of nanocellulose using highly crystalline bacterial cellulose (BC) as model nanocellulose was undertaken to achieve a comprehensive understanding of the limitations of BET method for nanocellulose. BET surface area obtained using volumetric N2 adsorption at −196°C was compared with the BET surface area acquired from gravimetric experiments based on n-octane adsorption using dynamic vapour sorption (DVS) and n-octane adsorption determined by inverse gas chromatography (iGC), both at 25°C. It was found that the BET surface area calculated from volumetric N2 adsorption data was 25% lower than that of n-octane adsorption at 25°C obtained using DVS and iGC adsorption methods. These results supported the hypothesis that the BET surface area of nanocellulose is both a molecular scale (N2vs n-octane, molecular cross section of 0.162 nm2vs 0.646 nm2) and temperature (−196°C vs 25°C) dependent property. This study also demonstrates the importance of selecting appropriate BET pressure range based on established criteria and would suggest that room temperature measurement is more relevant for many nanocellulose applications.

Mycelium composites are an emerging class of cheap and environmentally sustainable materials experiencing increasing research interest and commercialisation in the EU and USA for construction applications. These materials utilise natural fungal growth as a low energy bio-fabrication method to upcycle abundant agricultural by-products and wastes into more sustainable alternatives to energy intensive synthetic construction materials. Mycelium composites have customisable material properties based on their composition and manufacturing process and can replace foams, timber and plastics for applications, such as insulation, door cores, panelling, flooring, cabinetry and other furnishings. Due to their low thermal conductivity, high acoustic absorption and fire safety properties outperforming traditional construction materials, such as synthetic foams and engineered woods, they show particular promise as thermal and acoustic insulation foams. However, limitations stemming from their typically foam-like mechanical properties, high water absorption and many gaps in material property documentation necessitate the use of mycelium composites as non- or semi-structural supplements to traditional construction materials for specific, suitable applications, including insulation, panelling and furnishings. Nonetheless, useful material properties in addition to the low costs, simplicity of manufacture and environmental sustainability of these materials suggest that they will play a significant role in the future of green construction. Keywords: Fungal mycelium, Mechanical performance, Insulation properties, Fire safety, Water and termite resistance

Radical innovations for all aircraft systems and subsystems are needed for realizing future carbon-neutral aircraft, with hybrid-electric aircraft due to be delivered after 2035, initially in the regional aircraft segment of the industry. Electrical energy storage is one key element here, demanding safe, energy-dense, lightweight technologies. Combining load-bearing with energy storage capabilities to create multifunctional structural batteries is a promising way to minimize the detrimental impact of battery weight on the aircraft. However, despite the various concepts developed in recent years, their viability has been demonstrated mostly at the material or coupon level, leaving many open questions concerning their applicability to structural elements of a relevant size for implementation into the airframe. This review aims at providing an overview of recent approaches for structural batteries, assessing their multifunctional performance, and identifying gaps in technology development toward their introduction for commercial aeronautic applications. The main areas where substantial progress needs to be achieved are materials, for better energy storage capabilities; structural integration and aircraft design, for optimizing the mechanical-electrical performance and lifetime; aeronautically compatible manufacturing techniques; and the testing and monitoring of multifunctional structures. Finally, structural batteries will introduce novel aspects to the certification framework.

Birch (Betula pendula Roth.) and beech (Fagus sylvatica L.) solid wood and plywood were overmolded with polyamide 6 (PA 6) and polypropylene (PP) to investigate their mechanical properties and interfacial adhesion. In the case of PA 6, maximum tensile shear strengths values of more than 8 to 9 MPa were obtained for birch and beech, respectively. The values are comparable to bond strengths of commercial joints bonded with formaldehyde-containing amino-plastics. Perpendicular to the wood elements, bond strength values of 3 MPa was achieved for PA 6. The penetration of the polymers into the wood structure results in a non-densified interphase and subsequent plastic deformation of the wood structure beyond the interphase. These compressed areas influenced the interfacial adhesion and mechanical interlocking. SEM and XPS analysis revealed different interpenetration behavior of the polymers into the wood structure, with chemical interaction confirmed only for wood and PA 6 but not PP.

Stable, liquid phenolic froths have been produced by whipping air into a mixture of phenolic resole, catalyst and surfactant. These liquid froths can be moulded into desired shapes and cured to produce open porous phenolic foams. This method, which we call froth templating, has been scaled to produce macroporous phenolic foam panels with a size of 400 mm × 400 mm × 50 mm. The density of the phenolic foams can be tuned from 0.44 g/cm3 to 0.18 g/cm3 by controlling the energy input into the liquid formulation, i.e. whipping speed and time. Accordingly, the phenolic foams had elastic moduli ranging from 200 MPa to 50 MPa. The phenolic foams were pyrolysed to produce carbon foams with a carbon yield of 48%. The carbon foams had an open porous structure replicating the phenolic foam precursor and electric conductivity of 17 S/m. Keywords: Phenolic foams, Froth templating, Carbon foams, Mechanical properties

Safe, light, and high-performance engineering structures may be generated by adopting composite materials with stable damage process (i.e., without catastrophic delamination). Interlayer hybrid composites may fail stably by suppressing catastrophic interlayer delamination. This paper provides a detailed analysis of delamination occurring in poly(acrylonitrile-butadiene-styrene) (ABS) or polystyrene (PS) film interleaved carbon-glass/epoxy hybrid composites. The ABS films toughened the interfaces of the hybrid laminates, generating materials with higher mode II interlaminar fracture toughness (GIIC), delamination stress (σdel), and eliminating the stress drops observed in the reference baseline material, i.e., without interleaf films, during tensile tests. Furthermore, stable behaviour was achieved by treating the ABS films in oxygen plasma. The mechanical performance (GIIC and σdel) of hybrid composites containing PS films, were initially reduced but increased after oxygen plasma treatment. The plasma treatment introduced O-C=O and O-C-O-O functional groups on the PS surfaces, enabling better epoxy/PS interactions. Microscopy analysis provided evidence of the toughening mechanisms, i.e., crack deflection, leading plasma-treated PS to stabilise delamination.

Chitin and its derivative chitosan are popular constituents in wound-treatment technologies due to their nanoscale fibrous morphology and attractive biomedical properties that accelerate healing and reduce scarring. These abundant natural polymers found in arthropod exoskeletons and fungal cell walls affect almost every phase of the healing process, acting as hemostatic and antibacterial agents that also support cell proliferation and attachment. However, key differences exist in the structure, properties, processing, and associated polymers of fungal and arthropod chitin, affecting their respective application to wound treatment. High purity crustacean-derived chitin and chitosan have been widely investigated for wound-treatment applications, with research incorporating chemically modified chitosan derivatives and advanced nanocomposite dressings utilizing biocompatible additives, such as natural polysaccharides, mineral clays, and metal nanoparticles used to achieve excellent mechanical and biomedical properties. Conversely, fungi-derived chitin is covalently decorated with -glucan and has received less research interest despite its mass production potential, simple extraction process, variations in chitin and associated polymer content, and the established healing properties of fungal exopolysaccharides. This review investigates the proven biomedical properties of both fungal- and crustacean-derived chitin and chitosan, their healing mechanisms, and their potential to advance modern wound-treatment methods through further research and practical application.

Oil foams have been stabilized by using particles of oligomer of tetrafluoroethylene (OTFE). OTFE particles were dispersed in oil mixtures prior to aeration, to exclude the oil-repellency nature of the particles due to the formation of the metastable Cassie-Baxter state and properly evaluate the effects of contact angle on the foaming behavior. The particle contact angle (θY) against air/oil surfaces were controlled by changing a composition of two oils with different surface tension (n-heptane and methyl salicylate). The θY value increases with increasing a mole fraction of methyl salicylate, from 42° (for pure n-heptane) to 89° (for pure methyl salicylate). The air volume incorporated in the oils after aerating OTFE dispersions in the oil mixtures shows a maximum when θY = 55°. The flocculation of OTFE particles in bulk oils is responsible for the unexpected behavior of foaming observed when θY is relatively high. The increase in the degree of the flocculation reduces the effective concentration of OTFE particles in bulk oil, leading to the inefficient bubble stabilization. These findings suggest the efficient oil foaming using particles as a stabilizer is achieved by optimizing both the particle contact angle and the degree of flocculation in oils.

Water hardness not only constitutes a significant hazard for the functionality of water infrastructure but is also associated with health concerns. Commonly, water hardness is tackled with synthetic ion-exchange resins or membranes that have the drawbacks of requiring the awkward disposal of saturated materials and being based on fossil resources. In this work, we present a renewable nanopaper for the purpose of water softening prepared from phosphorylated TEMPO-oxidized cellulose nanofibrils (PT-CNF). Nanopapers were prepared from CNF suspensions in water (PT-CNF nanopapers) or low surface tension organic liquids (ethanol), named EPT-CNF nanopapers, respectively. Nanopaper preparation from ethanol resulted in a significantly increased porosity of the nanopapers enabling much higher permeances: more than 10,000× higher as compared to nanopapers from aqueous suspensions. The adsorption capacity for Ca2+ of nanopapers from aqueous suspensions was 17 mg g−1 and 5 mg g−1 for Mg2+; however, EPT-CNF nanopapers adsorbed more than 90 mg g−1 Ca2+ and almost 70 mg g−1 Mg2+. The higher adsorption capacity was a result of the increased accessibility of functional groups in the bulk of the nanopapers caused by the higher porosity of nanopapers prepared from ethanol. The combination of very high permeance and adsorption capacity constitutes a high overall performance of these nanopapers in water softening applications.

Developing nanomaterials that are effective, safe, and selective for gene transfer applications is challenging. Bacteriophages (phage), viruses that infect bacteria only, have shown promise for targeted gene transfer applications. Unfortunately, limited progress has been achieved in improving their potential to overcome mammalian cellular barriers. We hypothesized that chemical modification of the bacteriophage capsid could be applied to improve targeted gene delivery by phage vectors into mammalian cells. Here, we introduce a novel hybrid system consisting of two classes of nanomaterial systems, cationic polymers and M13 bacteriophage virus particles genetically engineered to display a tumor-targeting ligand and carry a transgene cassette. We demonstrate that the phage complex with cationic polymers generates positively charged phage and large aggregates that show enhanced cell surface attachment, buffering capacity, and improved transgene expression while retaining cell type specificity. Moreover, phage/polymer complexes carrying a therapeutic gene achieve greater cancer cell killing than phage alone. This new class of hybrid nanomaterial platform can advance targeted gene delivery applications by bacteriophage.

Carbon foams displaying hierarchical porosity and excellent surface areas of >1400 m2/g can be produced by the activation of macroporous poly(divinylbenzene). Poly(divinylbenzene) was synthesized from the polymerization of the continuous, but minority, phase of a simple high internal phase Pickering emulsion. By the addition of KOH, chemical activation of the materials is induced during carbonization, producing Pickering-emulsion-templated carbon foams, or carboHIPEs, with tailorable macropore diameters and surface areas almost triple that of those previously reported. The retention of the customizable, macroporous open-cell structure of the poly(divinylbenzene) precursor and the production of a large degree of microporosity during activation leads to tailorable carboHIPEs with excellent surface areas.