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.

Bioflex is a biodegradable polymer blend combining poly(butylene adipate-co-terephthalate) (PBAT) and bio-based poly(lactic acid) (PLA), offering properties comparable to polyethylene. However, challenges like limited processability and low mechanical properties restrict its use to agricultural films. In this study, fibers from end-of-life textiles (polyester, viscose, cotton, and silk) are used to address these limitations, demonstrating a resource-efficient approach to reducing landfill deposits. Adding fibers to the polymer blend (30 wt%) visibly improves the melt strength. The end-of-life fibers affect the mechanical properties in different ways: polyester fibers almost double the tensile strength, viscose fibers triples flexural strength, and silk fibers lead to the highest compressive strength. The retained colors of the fibers further contribute to vibrant composites, making them ideal for cosmetics packaging, household goods, fashion accessories, and toys. Additionally, the composting test revealed varied disintegration behaviors. Cotton and silk began disintegrating first, viscose followed, while polyester showed no disintegration, extending the composite's durability in use. This study highlights the potential of end-of-life textiles as an excellent reinforcement for Bioflex copolymer blends, promoting efficient resource use, reducing environmental waste, and unlocking new application areas for biodegradable polymers.

Utilization of biomass and reuse of industrial by-products and their sustainable and resource-efficient development into products that are inherently non-toxic is important to reduce the use of hazardous substances in the design, manufacture and application of biomaterials. The hypothesis in this study is that spent mushroom substrate (SMS), a by-product from mushroom production, has already undergone a biological pretreatment and thus, can be used directly as a starting material for fibrillation into value-added and functional biomaterial, without the use of toxic substances. The study show that SMS can be effectively fibrillated at a very high concentration of 6.5 wt % into fibrils using an energy demand of only 1.7 kWh kg−1, compared to commercial and chemically pretreated wood pulp at 8 kWh kg−1, under same processing conditions. SMS is a promising resource for fibrillation with natural antioxidant activity and network formation ability, which are of interest to explore further in applications such as packaging. The study shows that biological pretreatment can offer lower environmental impact related to toxic substances emitted to the environment and thus contribute to reduced impacts on categories such as water organisms, human health, terrestrial organisms, and terrestrial plants compared to chemical pretreatments.

A fungal biorefinery is presented to valorize food waste to fungal monofilaments with tunable properties for different textile applications. Rhizopus delemar is successfully grown on bread waste and the fibrous cell wall is isolated. A spinnable hydrogel is produced from cell wall by protonation of amino groups of chitosan followed by homogenization and concentration. Fungal hydrogel is wet spun to form fungal monofilaments which underwent post-treatments to tune the properties. The highest tensile strength of untreated monofilaments is 65 MPa (and 4% elongation at break). The overall highest tensile strength of 140.9 MPa, is achieved by water post-treatment. Moreover, post-treatment with 3% glycerol resulted in the highest elongation % at break, i.e., 14%. The uniformity of the monofilaments also increased after the post-treatments. The obtained monofilaments are compared with commercial fibers using Ashby's plots and potential applications are discussed. The wet spun monofilaments are located in the category of natural fibers in Ashby's plots. After water and glycerol treatments, the properties shifted toward metals and elastomers, respectively. The compatibility of the monofilaments with human skin cells is supported by a biocompatibility assay. These findings demonstrate fungal monofilaments with tunable properties fitting a wide range of sustainable textiles applications.

Wood–polymer composites (WPCs) with polypropylene (PP) matrix suffer from low toughness, and fossil-based impact modifiers are used to improve their performance. Material substitution of virgin fossil-based materials and material recycling are key aspects of sustainable development and therefore recycled denim fabric, and elastomer were evaluated to replace the virgin elastomer modifier commonly used in commercial WPCs. Microtomography images showed that the extrusion process fibrillated the denim fabric into long, thin fibers that were well dispersed within the WPC, while the recycled elastomer was found close to the wood fibers, acting as a soft interphase between the wood fibers and PP. The fracture toughness (KIC) of the WPC with recycled denim fabric matched the commercial WPC which was 1.4 MPa m1/2 and improved the composite tensile strength by 18% and E-modulus by 54%. Recycled elastomer resulted in slightly lower KIC, 1.1 MPa m1/2, as well as strength and modulus while increasing elongation and contributing to toughness. The results of this study showed that recycled materials can potentially be used to replace virgin fossil-based elastomeric modifiers in commercial WPCs, thereby reducing the CO2 footprint by 23% and contributing to more efficient use of resources.

The skin is the largest organ of the human body. Wounds disrupt the functions of the skin and can have catastrophic consequences for an individual resulting in significant morbidity and mortality. Wound infections are common and can substantially delay healing and can result in non-healing wounds and sepsis. Early diagnosis and treatment of infection reduce risk of complications and support wound healing. Methods for monitoring of wound pH can facilitate early detection of infection. Here we show a novel strategy for integrating pH sensing capabilities in state-of-the-art hydrogel-based wound dressings fabricated from bacterial nanocellulose (BC). A high surface area material was developed by self-assembly of mesoporous silica nanoparticles (MSNs) in BC. By encapsulating a pH-responsive dye in the MSNs, wound dressings for continuous pH sensing with spatiotemporal resolution were developed. The pH responsive BC-based nanocomposites demonstrated excellent wound dressing properties, with respect to conformability, mechanical properties, and water vapor transmission rate. In addition to facilitating rapid colorimetric assessment of wound pH, this strategy for generating functional BC-MSN nanocomposites can be further be adapted for encapsulation and release of bioactive compounds for treatment of hard-to-heal wounds, enabling development of novel wound care materials.

Hydrogels of cellulose nanofibrils (CNFs) are promising wound dressing candidates due to their biocompatibility, high water absorption, and transparency. Herein, two different commercially available wood species, softwood and hardwood, were subjected to TEMPO-mediated oxidation to proceed with delignification and oxidation in a one-pot process, and thereafter, nanofibrils were isolated using a high-pressure microfluidizer. Furthermore, transparent nanofibril hydrogel networks were prepared by vacuum filtration. Nanofibril properties and network performance correlated with oxidation were investigated and compared with commercially available TEMPO-oxidized pulp nanofibrils and their networks. Softwood nanofibril hydrogel networks exhibited the best mechanical properties, and in vitro toxicological risk assessment showed no detrimental effect for any of the studied hydrogels on human fibroblast or keratinocyte cells. This study demonstrates a straightforward processing route for direct oxidation of different wood species to obtain nanofibril hydrogels for potential use as wound dressings, with softwood having the most potential.

This study aimed to develop a manufacturing process for recycled textile long fiber thermoplastics (RT-LFT) and thereby contribute to circular economy. Three different post-consumer textiles (cotton denim and plain weave, and silk plain weave) were cut into strips and fed directly into a co-rotating twin-screw extruder in which the textile was fibrillated and compounded with polypropylene (PP). The fibrillation of the textile, fiber dispersion, and interaction with the matrix polymer were studied, and the thermal and mechanical properties of the composites were evaluated. For example, cotton denim composites containing 30 wt% fiber content resulted in 26% increase in yield strength and a 72% increase in modulus when compared with that of PP. The RT-LFT process is a straightforward method for transforming used textiles into composites like cups and bottoms, offering advantages such as reduced manufacturing costs, add value for waste material, and lower carbon emissions.