Spent mushroom substrates (SMS), a lignocellulosic residue from mushroom cultivation, represent a promising raw material for the valorization of nontoxic materials supporting the circular bioeconomy. The inherent biological pretreatment of the birch wood substrate during shiitake cultivation reduces the need for chemicals prior to fibrillation. SMS was fibrillated using an extruder and a blender at high (28 wt %) and low (5 wt %) solid contents, respectively, with and without a predispersion step. Extrusion proved to be the most energy-efficient method, requiring only 11 kWh/t, compared with 417 kWh/t for blending. When combined with predispersion, extrusion is the second most energy-efficient fibrillation method (789 kWh/t), compared to blending with predispersion (1195 kWh/t). Microscopy and fiber fractionation confirmed fibrillation into microfibers after extrusion and the presence of residual mycelium. Sheet formation by vacuum filtration over a coarse mesh significantly lowered the filtration time compared to a fine filter. Sheets produced from fibrillated SMS possessed tensile strength up to 7.5 times higher than commercial birch kraft pulp sheets prepared under the same conditions. The improved tensile strength is due to the presence of mycelial fibrils, which enhanced fiber–fiber bonding. Overall, extrusion provides a scalable, energy-efficient route for SMS fibrillation for the production of future all-natural materials without the need for chemical modification.

Carbon materials are widely investigated for electromagnetic (EM) shielding and absorption. However, designing sustainable and tunable architectures that span multiple EM functions remains challenging. Here, we present a renewable materials strategy based on biopolymer-derived carbon nanofiber sheets where both carbonization temperature and fiber alignment are used to tune EM attenuation. The sheets were fabricated via high-speed electrospinning followed by carbonization at 600–1000 °C, enabling systematic tuning of microstructure, anisotropy, porosity, electrical conductivity and dielectric response. The electrospinning process produced aligned nanofiber networks that upon carbonization developed into anisotropic conductive pathways. Carbonization at 1000 °C yielded highly porous sheets with a specific surface area of 926 m2g−1 without external activation. The temperature-driven structural evolution resulted in a distinct functional transition: dielectric transparency at 600 °C, broadband absorption at 700–800 °C, and highly conductive reflective-dominating shielding at 1000 °C. The optimized sheet achieved shielding effectiveness of 54 dB at 18.3  GHz and 44.5 dB at 1.0 THz. Electrical anisotropy further enabled orientation-dependent shielding differences of 16.4 dB (GHz) and 21.8 dB (THz). These results establish aligned, renewable carbon nanofiber sheets as scalable platforms for next generation microwave and terahertz technologies.

Reconfigurable intelligent surfaces (RISs) are key enabling technologies for next-generation wireless telecommunication systems, offering dynamic control over electromagnetic (EM) wave propagation. However, most existing RIS demonstrations rely on conventional electronic or metallic platforms, raising concerns about resource availability, recyclability, and environmental sustainability. In this study, hybrid nanostructured RIS prototypes (Prototypes I–III) were designed and fabricated using sustainable, wood-derived materials, namely, cellulose nanofibers (CNFs), suberin, and biocarbon, in combination with thermoresponsive vanadium dioxide (VO₂) nanoparticles. The EM performance of these RIS architectures was first optimized through full-wave simulations and then validated experimentally by the cast-layer deposition of VO₂/CNF–suberin functional layers onto printed circuit board (PCB) substrates. Among the tested designs, Prototype I, comprising a functional layer of 95 wt % VO₂, 2.5 wt % nonderivatized CNF, and 2.5 wt % suberin, exhibited the most pronounced thermal response, showing resonance frequency shifts of up to 19 MHz at a 5 GHz center frequency and phase shifts of 83° with temperature variation. Prototype II, containing cationic CNFs, demonstrated improved mechanical stability but reduced electrical continuity due to microstructural cracking, whereas Prototype III, modified with biocarbon, displayed diminished conductivity arising from its lower VO₂ content. Degree of linear polarization (DOLP) analysis revealed early stage phase transitions that occurred prior to complete conductive pathway formation. Overall, the hybrid RIS architectures developed from VO₂ and wood-derived materials through a sustainable processing route exhibited highly tunable, temperature-triggered EM modulation, with sensitivity ranging from low to high, depending on the material composition and assembly configuration.

This study investigates the use of X-ray microtomography (XMT) to reveal the structure of complex porous biological tissues and the fluid flow through them during wetting. It also evaluates fluid dynamical simulations based on XMT data to reproduce and analyse these flows, with a final aim of revealing fluid transport and void formation in such tissues. To fulfil the objectives, the wetting flow of a polymer liquid through an initially dry conditioned Norway spruce wood sample is visualised using XMT at the MAX IV synchrotron. The liquid flow front progression captured after 24 s and 48 s reveals uneven filling of longitudinal tracheids and flow between them via the tiny pits which connect tracheids. Most tracheids fill between 24 and 48 s, possibly due to removal of air inclusions. Large density gradients near cell walls suggest that the fluid followed and deposited along wall structures. Computational fluid dynamics simulations (CFD) of saturated flow through the tomography-based geometry indicate velocity profiles that resemble pipe flow in longitudinal tracheids and flow rate differences among them. The latter indicates that the geometry itself may cause the experimentally observed uneven flow. Streamlines show intra-tracheid flow development and clear flow direction change at the pits. Additionally, wetting simulations, using a constant contact angle, capture initial uneven filling between the tracheids on shorter time scales than could be capture by the experiments. These simulations furthermore show air entrapment during filling, consistent with experimental observations. Combining XMT with CFD enables detailed studies of flow in biological porous media. Faster X-ray scanning, incorporating dynamic contact angles and accounting for diffusion in simulations could further refine insights into fluid progression during capillary-driven flow into complex structures of porous biological tissues.

Wounds are highly prone to infection, which can delay healing and lead to severe complications such as gangrene and sepsis. Non-healing wounds significantly impact patients' physical and mental well-being and place a substantial financial burden on healthcare systems. Timely and effective treatment of wound infections is critical, but the rise of antibiotic-resistant pathogens complicates this process. In this study, we investigate a potent protease resistant antimicrobial peptide (AMP), PLNC8 αβ, for the treatment of wound infections and present a strategy for localized AMP delivery using functionalized advanced nanocellulose (NC) wound dressings. Two types of NC dressings were explored: bacterial cellulose (BC) and TEMPO-oxidized nanocellulose derived from wood powder (TC). In a porcine wound infection model, PLNC8 αβ exhibited high antimicrobial activity, successfully eradicating the infection while promoting wound re-epithelialization. To achieve controlled release of PLNC8 αβ from the NC dressings, the peptides were either physisorbed directly onto the nanofibrils or encapsulated within mesoporous silica nanoparticles (MSNs) that were incorporated into the dressings. The PLNC8 αβ functionalized dressings demonstrated low cytotoxicity toward human primary fibroblasts and keratinocytes. Both BC and TC dressings showed efficient contact inhibition of bacteria but were less effective in inhibiting bacteria in suspension. In contrast, MSN-functionalized dressings, displayed significantly enhanced peptide-loading and sustained release capacities, resulting in improved antimicrobial efficacy. These findings highlight the potential of PLNC8 αβ and PLNC8 αβ-functionalized nanocellulose wound dressings for the treatment of infected wounds, offering an effective alternative to conventional antibiotic therapies.

Underutilized co- and by-products are upgraded into materials with functional properties. The utilization of mushroom farming residues is investigated, specifically mushroom residues and spent mushroom substrate – whose chemical composition is determined – to produce cosmetic face masks, packaging films, and oil sorbents. Flexible mushroom sheets exhibit conformability and antioxidant activity between 82 and 94%, and better tensile strength in comparison with commercial cosmetic masks, making them suitable for such applications. Plasticization with glycerol increases the flexibility and tensile strain from ≈1 to 45% and moisture sorption from 32 to 100 wt.%. Spent mushroom substrate pulp yields stiff and strong rigid sheets with Young's moduli of 5 GPa and tensile strengths of 42 MPa. These sheets show 100% antioxidant activity, having hydrophobic behavior and oxygen barrier properties in dry conditions, and thus are promising for bioactive packaging applications. Foamed spent mushroom substrate sorbents demonstrate high affinity for both oil and water, with a water and oil uptake of 21 and 28 times their weight, respectively, while maintaining structural integrity. These properties make the foams viable as bio-based oil sorbents, highlighting the potential of by-products for advanced functional materials.

From an economic and environmental perspective, the use of less chemicals in the production of cellulose nanofibrils (CNFs) is advantageous. In this study, we investigated the oxidation (TEMPO/NaClO2/NaClO, pH 6.8) of softwood (SW) particles with varying amounts of TEMPO (16, 8 or 0 mg g−1 of wood). Following, TEMPO-oxidized SW nanofibrils (TO-SWNFs) were obtained by nanofibrillation and their size, morphology, and crystallite size were assessed. Hydrogel networks of TO-SWNFs were prepared and mechanical properties were measured in dH2O and phosphate buffered saline (PBS) to compare their performance for possible biomedical applications such as wound dressings. The results reveal that the presence of TEMPO is of importance for TO-SWNF network properties, presenting higher eq. H2O absorption (≈2500 %) and elongation at break (≈10 %) with good wet strength (≈180 kPa). In addition, a decrease in use of TEMPO catalyst from 16 to 8 mg g−1 of wood is possible, without detrimental effects on hydrogel network properties (dH2O absorption ≈ 2000 %, elongation at break ≈ 13 %, wet strength ≈ 190 kPa) related to applications as wound dressings.

Cellulose filaments with a unique microtape-like shape (width/thickness ratio ≈ 40) were studied for their potential as reinforcement in bio-epoxy resin with the hypothesis that their gross-sectional geometry would allow for efficient stress transfer and a higher transverse modulus. The microstructure of the spun filaments, orientation of the cellulose fibrils within them, and their mechanical properties were analyzed. Unidirectional (UD) composites with bio-epoxy resin were fabricated using vacuum infusion resulting in filament content of ≈ 23 vol% and low density 1.18 gcm−3.

Wide-angle X-ray scattering showed that the cellulose fibrils were relatively well aligned in the filament axis, having an orientation factor of 0.78. The axial filament modulus was measured to 33 GPa, the in-plane transverse modulus to 12 GPa and the axial strength was approx. 380 MPa. The longitudinal E-modulus of the UD composites was measured to 10 GPa and the strength to 120 MPa, both 3 times higher than the used bio-epoxy agreeing well with the estimated values. The transverse elongation at break of the UD composite was higher than typical values reported for glass-fiber epoxy composites, but the effect of filament shape on the transverse modulus was less significant than the predicted 4.5 GPa but still better than estimated for circular fibers. The lower property is likely due to the low filament content and the partially uneven in-plane filament arrangement. Simulations based on shear stress analysis suggest that the transverse properties of the UD composite could be improved by ensuring that the filament planes remain predominantly parallel in-plane during fabrication, and the overall mechanical properties could be improved by increasing the filament content.

Hierarchically porous, anisotropic, and green carbon aerogels (CAs) prepared from second most abundant and underutilized biopolymer lignin is used together with biobased epoxy resin to prepare green composite materials with superior mechanical properties. Green and facile preparation route involving ice-templating, lyophilization followed by carbonization was followed for the preparation of CAs. Ice-templating cooling rate is an important parameter in determining the porous structure of the CAs and by choosing a slower cooling rate bigger macropores can be achieved which facilitate the capillary impregnation of the epoxy resin through the CA structure. Hence in this study a cooling rate of 5 K/min was used and the CAs were prepared at 1000 °C from lignin/CNF suspensions containing 3, 5 and 7 wt% of total solid contents. Composites prepared using these CAs as reinforcements showed interesting morphologies which were analyzed using scanning electron microscopy and X-Ray microtomography. Prepared composites contained a mass fraction of 5–9 wt% of CAs. Composites showed remarkable 72 % higher dynamic mechanical properties compared to neat epoxy. Thus, this study introduces new synthesis strategy for carbon composites with completely biobased anisotropic CAs as oriented and strong reinforcements.

Wound infections result in delayed healing, morbidity, and increased risks of sepsis. Early detection of wound infections can facilitate treatment and reduce the need for the excessive use of antibiotics. Proteases are normally active during the healing process but are overexpressed during infection as part of the inflammatory response. Proteases are also produced by the bacteria infecting the wounds, making proteases a highly relevant biomarker for infection monitoring. Here, we show a fluorescence turn-on sensor for real-time monitoring of protease activity in advanced nanocellulose wound dressings for rapid detection of wound pathogens. Colloidal gold nanoparticles (AuNPs) were adsorbed on bacterial cellulose (BC) nanofibrils by using a carefully optimized self-assembly process. The AuNPs could either be homogeneously incorporated in BC dressings or 3D printed in wood-derived cellulose nanofiber (CNF) dressings using a BC-AuNP ink. The BC-adsorbed AuNPs were subsequently functionalized with fluorophore-labeled protease substrates. Cleavage of the substrates by proteases produced by the wound pathogens Staphylococcus aureus and Pseudomonas aeruginosa resulted in a significant increase in fluorescence that correlated with the growth phase of the bacteria. Wound dressing with integrated sensors for the detection of proteolytic activity can enable the sensitive and rapid detection of infections, allowing for optimization of treatment and reducing the risks of complications.