Modern wound care is challenged by the emergence of antibiotic-resistant bacterial strains, causing the need for advanced dressing materials that provide infection control while promoting healing. Although polyacrylamide (PAAm) hydrogels are widely investigated due to their biocompatibility, their lack of intrinsic antibacterial activity and poor mechanical properties restrict their clinical use. To overcome these limitations, this study proposes a natural–synthetic hydrogel that combines PAAm with TEMPO-oxidized cellulose nanofiber (TOCNF) functionalized silver nanoparticles (AgNPs). The synthesis is performed through the polymerization of the synthetic monomer in the presence of the TOCNF–AgNPs, the nanofibrillar cellulose simultaneously serving as a reducing and stabilizing agent for AgNPs, and as a plasticizer for the PAAm network. Morpho-structural analysis of the hybrid precursor (TOCNF–AgNPs) revealed two populations of AgNPs, offering a cumulative effect between rapid bacterial penetration and a prolonged ionic reservoir, while maintaining the stability of the system. The subsequent incorporation of the hybrid into PAAm matrix resulted in tunable swelling kinetics and mechanical properties. Wettability and surface stiffness improve with the increase in hybrid content. The antibacterial effect was confirmed by a colony-counting assay for formulations with higher AgNPs content, exhibiting inhibitory metabolic activity against several pathogenic strains. These results suggest that PAAm/TOCNF–AgNPs (PTA) nanocomposites represent a promising mechanically adaptive candidate for wound-care applications

Designing bioinks for bone tissue engineering (BTE) requires precise balancing of printability, stability and bioactivity. To address the trade-off between fabrication fidelity and osteogenic potential, we developed a novel multicomponent bioink composed of gelatin methacryloyl (GelMA), TEMPO-oxidized cellulose nanofibrils (TO-CNFs) and sodium alginate (SA), functionalized with a previously unexplored dual-nanoparticle (NP) system: nanodiamonds (NDs) and magnesium-doped nanohydroxyapatite (MgHA). Microstructural characterization confirmed spheroidal NDs (∼5 nm) and needle-like MgHA (∼200 × 50 nm), with aggregates forming co-localized organic–inorganic domains with NDs intercalated between MgHA particles. We evaluated the nanoparticles’ individual and combined effects on the rheology and printability of the inks, as well as on the structural integrity, biocompatibility and osteogenic performance of the 3D bioprinted constructs, hypothesizing complementary nanofiller functions. NDs improved printing fidelity and buildability, while MgHA supported osteogenic differentiation. The dual-loaded formulation demonstrated increased alkaline phosphatase activity, Runx2 expression and biomineralization, compared to single-nanofiller formulations. These findings demonstrate that the complementary effects of the dual NP system, embedded in a hydrated polymer matrix, provide a promising platform with robust printability and enhanced bioactivity for extrusion-based BTE constructs

In recent years, the incorporation of a ceramic phase such as nanohydroxyapatite (nHA) into gelatin methacryloyl (GelMA)-based bioinks has gained attention for extrusion-based bioprinting to replicate the inorganic mineral phase of bone tissue. However, the effects of different nHA concentrations in GelMA bioinks on printability, shape fidelity, long-term stability, cell viability, and osteogenic activity have not been fully investigated. Therefore, the current study investigates the incorporation of different concentrations of nHA (0, 1, 3 and 5% w/v) into GelMA/gelatin/nanocellulose bioink for printing human bone marrow-derived stromal cells for bone tissue engineering applications. As the concentration of nHA increased, the viscosity of the bioink also increased significantly. The bioink with the highest concentration of nHA failed to maintain the full height of the printed objects, while the bioinks containing only 1% nHA showed superior buildability and shape fidelity. Moreover, nHA particles hindered the photocrosslinking process in a concentration-dependent manner. Higher concentrations of nHA resulted in poor cross-linking, which negatively affected the stability of the printed structures under culture conditions. In combination, the increased viscosity and inadequate crosslinking at higher nHA concentrations had a detrimental effect on the cells: the 5% nHA bioink resulted in reduced cell viability and limited osteogenic differentiation. In contrast to the higher concentrations, the 1% nHA bioink supported high cell viability, maintained good metabolic activity and promoted osteogenic protein production (Runx2, Col-I, DMP1, OCN). This study highlights the importance of incorporating low concentrations of the nHA phase in multi-component bioinks for bone tissue engineering applications. Copyright

This study demonstrates an approach for incorporating cellulose nanofibrils (CNFs) into polyurethane (PU) using a solvent-free masterbatch consisting of 30% CNFs and 70% polyol, where the latter component functions as a carrier. This is the highest concentrated re-dispersible CNF-polyol system described to date. CNF addition produced strong shear-thinning behaviour, reduced the temperature sensitivity of viscosity, and maintained network integrity under conditions representative of PU curing. Power-law and Arrhenius modelling indicated that at low-to-medium shear rates the CNFs dominate rheological response, but the polyols rheological profile dominate at high shear rates when the fibrils occupy less space due to fluid flow alignment. Oscillatory tests showed increased elasticity and the transition from a viscous fluid toward gel-like behaviour at around 2% CNF loading. Cured CNF-PU composites exhibited increased stiffness, with microscopy revealing mechanically engaged fibrils within the fracture surfaces. Overall, CNFs provide an effective bio-based route to rheology modification PU systems, highlighting their potential in high-performance coatings and adhesives

Cellulose nanofibrils (CNFs) were incorporated into solvent-free epoxy resin using the masterbatch (MB) method to induce thixotropic rheology and provide reinforcement. This approach avoids irreversible agglomeration, which typically occurs when drying CNFs, and mitigates the inhalation risks associated with many common rheology agents in solvent-free epoxy applications. This study compares the rheological impacts of four CNF MBs containing 10%, 30%, 50%, and 70% CNF – representing the highest CNF dosages reported in solvent-free systems. The MB with 30% CNFs was further evaluated for its mechanical and hygroscopic properties in composites. The addition of 1% CNFs increased tensile strength by 98.5%, with no significant negative impact on impact strength, elasticity, or elongation. While the high viscosity obtained from CNF MBs can limit the use of CNFs in coatings to low dosages, the paste-like consistency attained at higher loadings may be advantageous for applications such as thermoset 3D printing, for which preliminary tests were conducted

Biobased food packaging barrier materials have not yet achieved broad adoption because they often fail to meet key requirements such as water vapor resistance, flexibility, and cost. Petroleum based plastics therefore remain dominant despite their environmental impact, driving the search for renewable and biodegradable alternatives. Cellulose esters have emerged as promising candidates, yet links between ester composition, molecular water interactions, and macroscopic barrier performance remain limited. Films of six commercially available cellulose acetate butyrates (CABs) and one cellulose acetate propionate (CAP) were investigated regarding water interactions, barrier performance, biodegradability, and thermal behavior. Composition dependent differences in hydration were observed, with CAP showing higher humidity and liquid water uptake than CAB. In contrast, macroscopic barrier properties, including water vapor permeability and water absorption, were weakly influenced by ester composition and instead governed by film morphology and processing history. Thermal analysis indicated that calorimetric features observed during first heating reflect the hydrated state of the films rather than crystalline melting. Biodegradation experiments showed limited but measurable soil degradation dependent on substitution chemistry. Overall, substitution chemistry controls molecular water interactions, while morphology and processing dominate macroscopic barrier performance, supporting cellulose esters as candidates for next generation food packaging. Copyright

This article studied the carboxylation of technical lignin and subsequent use as emulsion stabilizer. Oxidation was conducted with hydrogen peroxide under alkaline conditions. As both titration and Fourier-transform infrared spectroscopy (FTIR) showed, phenolic units were converted to carboxyl groups by oxidation. The treatment was most effective for soda lignin from Arkansas/straw, but also had significant effect on the softwood kraft lignin and softwood soda lignin. An increase in molecular weight by size-exclusion chromatography was further noted, which was less pronounced for the Arkansas/straw lignin. It was argued that one contributing mechanism was the monolignol composition, as the lignin from annual plants also contained S-units in addition to the G-units that mostly made up the softwood lignin. Moreover, purification prior to oxidation, i.e., removal of inorganic components in the lignin, showed no significant effect on the carboxylation process. Emulsion stabilization was studied with respect to the pH using three oxidized kraft lignins. Here, lower pH yielded better emulsion stabilization, unless the lignin precipitated, which switched the stabilization mechanism from interfacial adsorption to particle stabilization. It was argued that the degree of ionization played a key role, as a lower degree of ionization corresponded with better emulsion stability at the same ionic strength. At last, measurements of interfacial tension and interfacial rheology found that oxidized lignin behaved similar to water-soluble lignosulfonates and created viscoelastic interface layers. 

The European Commission's single-use plastics directive has put major restrictions on the use of chemically modified cellulosics for different material applications, e.g., as films, fibres, foams and other shaped objects. In addition, the wet strength and barrier properties of some of these materials are lacking, in comparison to petrochemical-based plastic materials. In the current study we demonstrate that it is possible to carry out surface selective acetylation of kraft fibre paper and nano-paper to create materials that maintain biodegradability. This is shown to be highly dependent on the degree of bulk acetylation, with those materials with modification restricted to fibril surface monoacetylation offering fine control over enzymatic digestibility. Materials which show the formation of cellulose triacetate were much less degradable in the timeframe of our assessment methods. However, the wet strength and extensibility of these materials was significantly improved, pushing the envelope for application towards moisture-rich environments. The mechanistic component of our study shows acetylation occurs down to the elementary fibril surface level, and not just on the macrofibre, or fibrillar bundle, level. We believe that this study offers a strong basis for widening the application scope of cellulosics towards traditionally petrochemical-based synthetic plastics. This journal is

In this work, dialdehyde cellulose microfibrils (DA-CMFs) were reacted with O-substituted hydroxylamines, demonstrating an effective and versatile method for lateral functionalization of DA-CMFs using mild, aqueous reaction conditions. Depending on the conditions used, partial or complete substitution of the aldehydes could be achieved. The reaction was performed in the presence and absence of the reducing agent α-picoline borane (PB). DA-CMFs were reacted with O-(carboxymethyl) hydroxylamine (HAAA), and the adhesive properties of native and HAAA-conjugated DA-CMFs to fibres were studied. The adhesive properties were shown to depend on charge; while native DA-CMFs aggregate heavily in contact with the fibre surface, HAAA-conjugated DA-CMFs showed significantly improved adhesion. For a degree of substitution of 50% or higher, a sealed layer, without aggregates, could be observed using electron microscopy. Finally, a versatile protocol for co-insertion of HAAA (carboxylate) and aminooxy-PEG<inf>3</inf>-azide (hydroxylamine azide) was developed and demonstrated, with high yields of insertion. The modified DA-CMFs retained good adhesive properties to fibres, showing that the approach is general, and that the chemistry can be tuned depending on the target application

Wood-derived TEMPO-oxidized cellulose nanofibrils (CNFs) have potential as scaffolding for bone tissue engineering. Although biocompatible, the material lacks osteoconductive and appropriate mechanical properties. Incorporation of nano-hydroxyapatite (nHA) and modification of scaffold preparation methods could improve applicability. In this study, freeze-dried porous scaffolds were prepared using a range of nHA (0, 20, 33, 50%) and CNF compositions. Not only the microarchitecture but also the chemical composition of the scaffolds was studied. Osteoblast-like osteosarcoma derived cells (Saos-2) were cultured on the scaffolds and their responses (viability, attachment, proliferation, and osteogenic phenotype) to the different scaffolds were documented. The results show that incorporation of nHA influenced the microarchitecture, mechanical stiffness and surface properties of the scaffolds. Moreover, biological characterization demonstrated good cell viability in all the groups. However, the increase of nHA concentration beyond 20% does not offer further advantages. It is concluded that the incorporation of 20% nHA resulted in the widest and most biomimetic pore size distribution, increased surface roughness and improved protein adsorption. These changes in material properties enhanced cell spreading and the osteogenic gene expression of osteoblast-like cells seeded on the scaffolds. Moreover, 20% nHA warrants further investigation as a potential scaffolding material for bone tissue engineering. Graphical abstract: (Figure presented.).