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In this study, a novel hydrogel, β-cyclodextrin/carbon dots-grafted cellulose nanofibrils hydrogel (βCCH), was fabricated for removal and fluorescence determination of levofloxacin (LEV). A comprehensive analysis was performed to characterize its physicochemical properties. Batch adsorption experiments were conducted, revealing that βCCH reached a maximum adsorption capacity of 1376.9 mg/g, consistent with both Langmuir and pseudo-second-order models, suggesting that the adsorption process of LEV on βCCH was primarily driven by chemical adsorption. The removal efficiency of βCCH was 99.2 % under the fixed conditions (pH: 6, initial concentration: 20 mg/L, contact time: 300 min, temperature: 25 °C). The removal efficiency of βCCH for LEV still achieved 97.3 % after five adsorption-desorption cycles. By using βCCH as a fluorescent probe for LEV, a fast and sensitive method was established with linear ranges of 1-120 mg/L and 0.2-1.0 μg/L and a limit of detection (LOD) as low as 0.09 μg/L. The viability of βCCH was estimated based on the economic analysis of the synthesis process and the removal of LEV, demonstrating that βCCH was more cost-effective than commercial activated carbon. This study provides a novel approach for preparing a promising antibiotic detection and adsorption material with the advantages of stability, and cost-effectiveness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In this study, an antibacterial material (CNF@CoMn-NS) with oxidase-like activity was created using ultrathin cobalt‑manganese nanosheets (CoMn-NS) with a larger specific surface area grown onto pineapple peel cellulose nanofibrils (CNF). The results showed that the CoMn-NS grew well on the CNF, and the obtained CNF@CoMn-NS exhibited good oxidase-like activity. The imidazole salt framework of the CNF@CoMn-NS contained cobalt and manganese in multiple oxidation states, enabling an active redox cycle and generating active oxygen species (ROS) such as singlet molecular oxygen atoms ( 1 O 2 ) and superoxide radical (·O 2 - ), resulting in the significant inactivation of Staphylococcus aureus (74.14%) and Escherichia coli (54.87%). Importantly, the CNF@CoMn-NS did not exhibit cytotoxicity. The CNF@CoMn-NS further self-assembled into a CNF@CoMn-NS paper with flexibility, stability, and antibacterial properties, which can effectively protect the wound of two varieties of pears from decay caused by microorganisms. This study demonstrated the potential of using renewable and degradable CNF as substrate combined with artificial enzymes as a promising approach to creating antibacterial materials for food preservation and even extending to textiles and biomedical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

With water access challenged, there is a need to develop efficient and sustainable alternatives for water purification. Here, cellulose nanofibrils (CNFs) isolated from three source materials (softwood, soybean hulls and oat straw) were compared for the generation of hydrogels beads, and compared as support and reducing agent for silver nanoparticles formation. The silver-functionalized hydrogel beads (Ag-CNFs) were characterized, and the surface energy and specific surface area were evaluated. Antimicrobial testing was conducted to assess the efficacy of the Ag-CNFs against E. coli. The results showed that the Ag-CNFs had a higher specific surface area and lower surface energy compared with unmodified CNFs. Softwood-based Ag-CNFs exhibited the highest silver content and specific surface area, while the soybean hull based showed the highest hydrophobic character. The silver-functionalized soybean hull beads (Ag-sbCNF) showed the highest efficacy in reducing the growth of bacteria. Overall, this study highlights the potential of silver-functionalized CNFs hydrogel beads as a promising environmentally friendly and sustainable material for water filtration and disinfection. The findings also suggest that lower surface energy of the Ag-CNFs play an important role in their antimicrobial effect on tested water by enabling shorter retention, providing useful insights into the design of future water filtration materials., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Maria S. Peresin reports financial support was provided by National Science Foundation. Maria S. Peresin reports financial support was provided by National Institute of Food and Agriculture. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

To address the issue of bisphenol A (BPA) contamination in wastewater, a novel hydrogel, sodium alginate/cellulose nanofibrils/ZIF-8 composite hydrogel (SCZC), was synthesized for efficient BPA removal. The SCZC exhibited an exceptional adsorption capacity of 1696 mg/g, aligning well with both Langmuir and pseudo-second-order models. Furthermore, it exhibited remarkable regeneration properties, maintaining 89.1 % of its adsorption capacity even after undergoing five adsorption-desorption cycles. The synthesized SCZC also acted as a fluorescent sensor for detecting BPA, employing dynamic quenching and offering linear detection ranges of 10-100 mg/L and 0.2-1.0 μg/L, with a low detection limit of 0.06 μg/L. Analysis of adsorption and detection mechanisms revealed that SCZC's exceptional performance could be attributed to the three-dimensional (3D) porous structure formed by sodium alginate and cellulose nanofibrils. Economic analysis indicated that SCZC, in comparison to commercially activated carbon, was relatively inexpensive. This study introduces a novel approach for designing and preparing a sodium alginate-based hydrogel incorporating metal-organic frameworks, offering simultaneous BPA detection and removal capabilities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Nanostructured materials are fascinating since they are promising for intensely enhancing materials' performance, and they can offer multifunctional features. Creating such high-performance nanocomposites via effective and mild approaches is an inevitable requirement for sustainable materials engineering. Nanocomposites, which combine two-star nanomaterials, namely, cellulose nanofibrils (CNFs) and graphene derivatives (GNMs), have recently revealed interesting physicochemical properties and excellent performance. Despite numerous studies on the production and application of such systems, there is still a lack of concise information on their practical uses. In this review, recent progress in the production, modification, properties, and emerging uses of CNFs/GNMs hybrid-based nanocomposites in various fields such as flexible energy harvesting and storage, sensors, adsorbents, packaging, and thermal management, among others, are comprehensively examined and described based on recent investigations. Nevertheless, numerous challenges and gaps need to be addressed to successfully introduce such nanomaterials in large-scale industrial applications. This review will certainly help readers understand the design approaches and potential applications of CNFs/GNMs hybrid-based nanocomposites for which new research directions in this emerging topic are discussed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Magnetic superhydrophobic materials have broad application prospect in oil-water separation. In this study, a magnetic and superhydrophobic aerogel with lamellar structure was successfully prepared using cellulose nanofibrils (CNF) as the skeleton, Fe 3 O 4 as the magnetic ion, 1H, 1H, 2H, 2H trialkylfluorooctane triethoxysilane (FS) and 3-(2-aminoethyl amino)-propyl trimethoxysilane (AS) as the combined modifier. The prepared aerogel shows lower density (38.63 mg/cm 3 ), excellent magnetic (15.13 emu/g), high elasticity and good oil sorption properties (21 g/g). In addition, FS/AS also exhibits excellent mechanical properties and superhydrophobic ability (water contact angle (WCA) of 151.9 ± 1.4°), as it provides sufficient toughness and low surface energy for the layer-branch structure. It should be noted that the entire preparation process is carried out in the aqueous phase, without the use of any organic solvents, providing a green oil-water separation strategy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

With the depletion of fossil fuels and growing environmental concerns, the modernized era of technology is in desperate need of sustainable and eco-friendly materials. The industrial sector surely has enough resources to produce cost-effective, renewable, reusable, and sustainable raw materials. The family of very porous solid materials known as aerogels has a variety of exceptional qualities, such as high porosity, high specific surface area, ultralow density, and superior thermal, acoustic, and dielectric properties. As a result, aerogels have the potential to be used for many different purposes, such as absorbents, supercapacitors, energy storage, and catalytic supports. Recently, cellulose nanofibril (CNF) aerogels have attracted remarkable attention for their large-scale utilization because of their high absorption capacity, low density, biodegradability, large surface area, high porosity, and biocompatibility. Recent advancements have confirmed that CNF-based hybrid aerogels can be proposed as the most privileged and promising novel material in various applications. This comprehensive review highlights the recent reports of the CNF-based hybrid aerogels, including their properties and frequent preparation approaches, in addition to their new applications in the areas of fire retardant, water and oil separation, supercapacitors, environmental, and CO 2 capture. It is also assumed that this article will promote additional investigation and establish innovative capabilities to enhance novel CNF-based hybrid aerogels with new and exciting applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. All the authors declare that there is no conflict of interest to publish our manuscript entitled “Review on recent developments in Cellulose nanofibril based hybrid Aerogels: Synthesis, Properties and their Applications” in International Journal of Biological Macromolecules., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A large number of polluting substances, including chlorinated organic substances that were highly stable and hazardous, has been emitted due to the rapidly developing chemical industry, which will affect the ecological environment. Nanocellulose aerogels are effective carriers for adsorption of oil substances and organic solvents, however, the extremely strong hydrophilicity and poor mechanical properties limited their widespread applications. In this study, TEMPO-oxidized cellulose nanofibrils was modified with 2, 4-toluene diisocyanate (TDI) and 4,4'-diphenylmethane diisocyanate (MDI) to prepare strong and hydrophobic aerogels for oil adsorption. The main purpose was to evaluate and compare the effects of two diisocyanates on various properties of modified aerogels. It was found that the modified aerogel had better hydrophobic properties, mechanical properties and adsorption properties. In particular, the modified aerogel with TDI as crosslinker showed a better performance, with a maximum chloroform adsorption capacity of 99.3 g/g, a maximum water contact angle of 131.3°, and a maximum compression stress of 36.3 kPa. This study provides further evidence of the potential of functional nanocellulose aerogel in addressing environmental pollution caused by industrial emissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Poly(vinyl alcohol) (PVA) biocomposite films reinforced with cellulose nanofibrils (CNF) and biologically active tannic acid (TA) were prepared. The influence of different concentrations of CNF and TA in the PVA polymer matrix was investigated in terms of mechanical properties, thermal properties and hydrophobicity improvement of the prepared films. The results showed that in all cases the addition of CNF and TA improved the values of tensile strength and elastic modulus. The PVA film with 10 % CNF exhibited a 30 % higher tensile strength, and the three-component PVA film with 2 % CNF and 10 % TA (P2C10T) exhibited a 40 % higher tensile strength compared to the neat PVA film. The thermal properties (T g , T onset ) of the PVA biocomposite films were greatly improved, with a significant effect observed for the three-component PVA films. The T g of the PVA film with 10 % CNF and 10 % TA was 87 °C, 12 °C higher than that of the neat PVA film. For three-component PVA biocomposites with 4 % and 6 % CNF and with all weight percentages of TA, the T onset shifted to a higher temperature range by about 30 °C compared to the neat PVA film. The PVA film with 2 % CNF and 10 % TA exhibited about a 20° higher contact angle than the neat PVA film. Moreover, the addition of both fillers to the PVA matrix resulted in PVA biocomposites with lower water absorption. PVA film with 10 % TA absorbed about 90 % less water and PVA film with 10 % CNF and 10 % TA absorbed about 80 % less water than the neat PVA film after the films were soaked in water for one hour. The better properties of the composite films produced are due to hydrogen and ester bonds between the components of the composite, which was confirmed by FT-IR spectroscopy. Antioxidant effective films were also obtained due to the biologically active TA to the PVA and PVA/CNF systems., Competing Interests: Declaration of competing interest The authors declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Cellulose aerogels exhibit biocompatibility and biodegradability, rendering them promising candidate for application in building energy conservation and insulation materials. However, the intrinsic inflammability of pristine cellulose aerogel causes unneglectable safety concerns, hindering their application in energy-efficient buildings. Herein, a thermal insulating, fire-retardant, strong, and lightweight aerogel was produced via freeze-casting suspensions of cellulose nanofibril (CNF) and l-glutamine functionalized boron nitride nanosheets (BNNS-g). The aerogel with a BNNS-g:CNF concentration ratio of 15:5 exhibited outstanding mechanical strength owing to the strong interaction between BNNS-g and CNF as well as satisfactory thermal insulating performance (0.052 W/m·K). Particularly, this aerogel showed excellent fire-retardant and self-extinguishing capabilities in the vertical burning test, which remained unscathed after over 60 s of burning in a butane flame. Further, the limit oxygen index (LOI) of this aerogel was 36.0 %, which was better than the LOIs of traditional petrochemical-based insulating materials. This study provides a promising strategy for producing aerogels with excellent properties using cellulose and other inorganic nano-fillers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Conjunctival reconstruction using biocompatible polymers constitutes an effective treatment for conjunctival scarring and associated visual impairment. In this work, a thin film comprising silk peptide (SP), cellulose nanofibrils (CNF) and Ag nanoparticles (AgNPs) that implanted on the poly(lactic acid) (PLA) electrospun fibrous membranes (EFMs) was designed for biomedical reconstruction. SP and CNF as thin films can improve the surface hydrophilicity of the as-prepared scaffolds, which synergistically enhanced the biocompatibility. In in vivo experiments, the developed PLA EFMs modified with 3 wt% SP/CNF/AgNPs could be easily manipulated and transplanted onto conjunctival defects in rabbits, consequently accelerating the structural and functional restoration of the ocular surface in 12 days. Additionally, incorporation of 0.30 mg/g AgNPs efficiently reduced the topical application of antibiotics without causing infections. Thus, these resultant scaffolds could not only serve as useful alternatives for conjunctival engineering, but also prevent infections effectively with a very low content of AgNPs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The usage of low-cost, readily available, or even disposable, single-use membranes in macromolecules' purification and separation is still in the development phase. In this research, highly porous (>95 %), water- and compression stable cation-exchange membranes were prepared by freeze-casting using cellulose nanofibrils (CNF) and citric acid (CA) acting as a crosslinker and source of weak anionic (carboxylic) surface groups arising from the mono-esterified CA. The membranes were characterized by different analytical techniques, and evaluated for the ionic adsorption efficacy of different proteins in dead-end filtration mode using a Tri-buffer of pH 8. The membrane's internal microstructure (porosity and density) with the available (quantity and access) carboxylic groups was confirmed, to determine not only the proteins' specific (related to the net charged and molecular weight) adsorption dynamic (>52 % of positive Lysozyme/Cytochrome, <8 % of negative BSA/Myoglobin; ≤0.5 g/L) at extremely high flow rates (>3.000 hL/h*MPa*m 2 ), but also their desorption (>97 %) and re-equilibration (using NaCl) with flux recovery (>80 %). Such efficiency was achieved with up to 5 consecutive filtering cycles. The high permeability (>87 %) of the spherical and negatively surface charged microparticles (used as models) also suggests the likelihood of removing larger microbial species, which, while retaining relatively smaller and positively charged proteins, further increases their potential in biopharma applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Cellulose nanofibrils (CNFs) are increasingly used as precursors for foams, films and composites, where water interactions are of great importance. In this study, we used willow bark extract (WBE), an underrated natural source of bioactive phenolic compounds, as a plant-based modifier for CNF hydrogels, without compromising their mechanical properties. We found that the introduction of WBE into both native, mechanically fibrillated CNFs and TEMPO-oxidized CNFs increased considerably the storage modulus of the hydrogels and reduced their swelling ratio in water up to 5-7 times. A detailed chemical analysis revealed that WBE is composed of several phenolic compounds in addition to potassium salts. Whereas the salt ions reduced the repulsion between fibrils and created denser CNF networks, the phenolic compounds - which adsorbed readily on the cellulose surfaces - played an important role in assisting the flowability of the hydrogels at high shear strains by reducing the flocculation tendency, often observed in pure and salt-containing CNFs, and contributed to the structural integrity of the CNF network in aqueous environment. Surprisingly, the willow bark extract exhibited hemolysis activity, which highlights the importance of more thorough investigations of biocompatibility of natural materials. WBE shows great potential for managing the water interactions of CNF-based products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Bacterial nanocellulose (BNC), due to its inherent nanometric scale and strength properties, can be considered as a good candidate to be used in papermaking. This work explored the possibility of using it in the production of fine paper as a wet-end component and for the paper coating. Filler-containing handsheet production was performed with and without the presence of common additives typically used in the furnish of office papers. It was found that, under optimized conditions, BNC mechanically treated by high-pressure homogenization could improve all the evaluated paper properties (mechanical, optical and structural) without impairing the filler retention. However, paper strength was improved only to a small extent (increase in the tensile index of 8 % for a filler content of ca. 27.5 %). On the other hand, when used at the paper surface, remarkable improvements in the gamut area of >25 % in comparison to the base paper and of >40 % in comparison to starch-only coated papers were achieved for a formulation having 50 % BNC and 50 % of carboxymethylcellulose. Overall, the present results highlight the possibility of using BNC as a paper component, particularly when applied at the paper substrate as a coating agent aiming at improving printing quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

To develop a greener and more efficient method for producing cellulose nanofibers (CNFs) from raw plants, an AlCl 3 -enhanced ternary deep eutectic solvent, DES2 (consisting of choline chloride, citric acid, and AlCl 3 ·6H 2 O in a molar ratio of 1:0.4:0.08), was synthesized. Raw elephant grass (EG) was pretreated with DES2, followed by sodium chlorite (NaClO 2 ) bleaching and ultrasonic disruption to extract high-performance CNFs. The DES2 and NaClO 2 treatments effectively removed hemicellulose and lignin, achieving removal rates of 99.23 % and 99.62 %, respectively, while maintaining a cellulose content of 78.3 %. DES2 demonstrated easy recyclability and maintained excellent biomass pretreatment performance even after multiple cycles. Following a brief 30-min intermittent ultrasound treatment, the resulting CNFs demonstrated superior crystallinity, increased carboxyl content, and a narrower width distribution compared to CNFs obtained from AlCl 3 -free DES1. Optimized conditions at 110 °C yielded CNFs with 85.3 % crystallinity, 0.64 mmol/g carboxyl content, 5.15 nm width distribution, and excellent dispersion in water for at least six months. Additionally, CNFs enhanced the tensile strength of chia seed mucilage (CM) composite films, showing a significant improvement to 26.6 MPa, representing a 231.3 % increase over the control film. This study offers a promising approach for efficiently producing CNFs from raw plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Enzymatic processing is considered a promising approach for advancing environmentally friendly industrial processes, such as the use of endoglucanase (EG) enzyme in the production of nanocellulose. However, there is ongoing debate regarding the specific properties that make EG pretreatment effective in isolating fibrillated cellulose. To address this issue, we investigated EGs from four glycosyl hydrolase (GH) families (5, 6, 7, and 12) and examined the roles of the three-dimensional structure and catalytic features, with a focus on the presence of a carbohydrate binding module (CBM). Using eucalyptus Kraft wood fibers, we produced cellulose nanofibrils (CNFs) through mild enzymatic pretreatment, followed by disc ultra-refining. Comparing the results with the control (without pretreatment), we observed that GH5 and GH12 enzymes (without CBM) reduced fibrillation energy by approximately 15 %. The most significant energy reduction, 25 and 32 %, was achieved with GH5 and GH6 linked to CBM, respectively. Notably, these CBM-linked EGs improved the rheological properties of CNF suspensions without releasing soluble products. In contrast, GH7-CBM exhibited significant hydrolytic activity, resulting in the release of soluble products, but did not contribute to a reduction in fibrillation energy. This discrepancy can be attributed to the large molecular weight and wide cleft of GH7-CBM, which led to the release of soluble sugars but had little impact on fibrillation. Our findings suggest that the improved fibrillation observed with EG pretreatment is primarily driven by efficient enzyme adsorption on the substrate and modification of the surface viscoelasticity (amorphogenesis), rather than hydrolytic activity or release of products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Pickering emulsions represent a promising avenue in the field of controlled drug delivery systems. Recently, cellulose nanofibers (CNFs) and chitosan nanofibers (ChNFs) have gained interest as eco-friendly stabilizers for Pickering emulsions, yet their application in pH-responsive drug delivery systems remains unexplored. However, the potential of these biopolymer complexes in formulating stable, pH-responsive emulsions for controlled drug release is of significant interest. Here, we show the development of a highly stable, pH-responsive fish oil-in-water Pickering emulsion stabilized by ChNF/CNF complexes, with optimal stability achieved at a 0.2 wt% ChNF concentration and an average emulsion particle size of approximately 4 μm. Our results demonstrate long-term stability (16 days of storage) for ChNF/CNF-stabilized emulsions, with the interfacial membrane's pH modulation facilitating controlled, sustained ibuprofen (IBU) release. Furthermore, we observed a remarkable release of approximately 95 % of the embedded IBU within the pH range of 5-9, while the drug loading and encapsulation efficiency of the drug-loaded microspheres reached their peak at a 1 % IBU dosage, with values of 1 % and 87 %, respectively. This study highlights the potential of using ChNF/CNF complexes in designing versatile, stable, and entirely renewable Pickering systems for controlled drug delivery, with potential applications in food and eco-friendly products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

In this work, nanofibrillated cellulose (NFC) was extracted from cactus Cereus jamacaru DC. (mandacaru) for nanopaper production. The technique adopted includes alkaline treatment, bleaching, and grinding treatment. The NFC was characterized according to its properties and scored based on a quality index. Particle homogeneity, turbidity, and microstructure of the suspensions were evaluated. Correspondingly, the optical and physical-mechanical properties of the nanopapers were investigated. The chemical constituents of the material were analyzed. The sedimentation test and the zeta potential analyzed the stability of the NFC suspension. The morphological investigation was performed using environmental scanning electron microscopy (ESEM) and transmission electron microscopy (TEM). X-ray diffraction (XRD) analysis revealed that Mandacaru NFC has high crystallinity. Thermogravimetric analysis (TGA) and mechanical analysis were also used and revealed good thermal stability and good mechanical properties of the material. Therefore, the application of mandacaru is interesting in sectors such as packaging and electronic device development, as well as in composite materials. Given its score of 72 points on a quality index, this material was presented as an attractive, facile, and innovative source for obtaining NFC., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Hydrogels with prominent flexibility, versatility, and high sensitivity play an important role in the design and fabrication of wearable sensors. In particular, these flexible conductive hydrogels exhibit elastic modulus that is highly compatible with human skin, demonstrating the great potential for flexible sensing. However, the preparation of high-performance hydrogel-based sensors that can restrain extreme cold conditions is still challenging. Herein, a novel anti-freezing composite hydrogel with superior conductivity based on polyacrylamide (PAM), LiCl, and PEDOT:PSS coated cellulose nanofibrils (PAM/PEDOT:PSS/CNF) is constructed. The addition of CNF increased the hydrogen bonding sites of the molecular chains in the micro, thus improving the mechanical strength and the conductivity of the hydrogel in the macro. The hydrogels achieve a high tensile strength of 0.19 MPa, compressive strength of 0.92 MPa, and dissipation energy of 41.9 kJ/m 3 . Otherwise, LiCl increases the interactions between the colloidal phase and water molecules, endowing the hydrogels with excellent freezing tolerance. Specifically, the optimized hydrogel of 45 % LiCl exhibited stable mechanical properties at -40 °C. Finally, the composite hydrogel was used to assemble flexible sensors with high sensitivity of 10.3 MPa -1 , which can detect a wide range of human movements and physiological activities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Cellulose nanofibrils (CNFs) have gained much attention as part of biocompatible soft hydrogels used in various biomedical applications such as biodegradable scaffolds, biomedicine, tissues, and regenerative medicine. The CNF hydrogels were mediated with metal cations for improved mechanical strength and structural reversibility. Intermolecular interactions in these CNF hydrogels are controlled by metal cation-carboxylate coordination bonding, leading to the creation of interconnected three-dimensional nanofibril structures that produce high structural reversibility. The nonlinear inter- and intra-cycle were investigated viscoelastic responses of these CNF hydrogels by quantitative nonlinear viscoelastic parameters and transient responses. The dynamic and transitional analyses conducted indicate that the structural deformation and recovery characteristics of the CNF hydrogels are affected by the valency number of the metal cations. This property can be carefully chosen to tune the intermolecular interactions between the cellulose nanofibrils to create an efficient interwoven network structure with high structural reversibility that can go through repeated cycles of reformation and yielding., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Improving the redispersion and recycling of dried cellulose nanofibrils (CNFs) without compromising their nanoscopic dimensions and inherent mechanical properties are essential for their large-scale applications. Herein, mixed-linkage (1,3;1,4)-β-d-glucan (MLG) was studied as a rehydration medium for the redispersion and recycling of dried CNFs, benefiting from the intrinsic affinity of MLG to both cellulose and water molecules as inspired from plant cell wall. MLG from barley with a lower molar ratio of cellotriosyl to cellotetraosyl units was found homogeneously coated on CNFs, facilitating rehydration of the network of individualized CNFs. The addition of barley MLG did not impair the mechanical properties of the CNF/MLG composites as compared to neat CNFs nanopaper. With the addition of 10 wt% barley MLG, dry CNF/MLG composite film was successfully redispersed in water and recycled with well-maintained mechanical properties, while lichenan from Icelandic moss, cationic starch, and xyloglucan could not help the redispersion of dried CNFs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

Cellulose nanofibrils (also called cellulose nanofibers or nanofibrillated cellulose [CNFs]) are novel polymers derived from biomass with excellent physicochemical properties and various potential applications. However, the introduction of such new materials into the market requires thorough safety studies to be conducted. Recently, toxicity testing using cultured cells has attracted attention as a safety assessment that does not rely on experimental animals. This article reviews recent information regarding the cytotoxicity testing of CNFs and highlights the issues relevant to evaluating tests. In the literature, we found that a variety of cell lines and CNF exposure concentrations was evaluated. Furthermore, the results of cytotoxicity results tests differed and were not necessarily consistent. Numerous reports that we examined had not evaluated endotoxin/microbial contamination or the interaction of CNFs with the culture medium used in the tests. The following potential specific issues involved in CNF in vitro testing, were discussed: (1) endotoxin contamination, (2) microbial contamination, (3) adsorption of culture medium components to CNFs, and (4) changes in aggregation/agglomeration and dispersion states of CNFs resulting from culture medium components. In this review, the available measurement methods and solutions for these issues are also discussed. Addressing these points will lead to a better understanding of the cellular effects of CNFs and the development of safer CNFs., (© 2022 The Authors. Journal of Applied Toxicology published by John Wiley & Sons Ltd.)

Natural polymer-based sutures have attractive cytocompatibility and degradability in surgical operations. Herein, anionic cellulose nanofibrils (ACNF) and cationic guar gum (CGG) are employed to produce nontoxic CGG/ACNF composite filament with a unique core-shell structure via interfacial polyelectrolyte complexation (IPC) spinning. The comprehensive characterization and application performance of the resultant CGG/ACNF filament as a surgical suture are thoroughly investigated in comparison with silk and PGLA (90% glycolide and 10% l-lactide) sutures in vitro and in vivo, respectively. Results show that the CGG/ACNF filament with the typical core-shell structure and nervation pattern surface exhibits a high orientation index (0.74) and good mechanical properties. The tensile strength and knotting strength of CGG/ACNF suture prepared by twisting CGG/ACNF filaments increase by 69.5%, and CGG/ACNF suture has a similar friction coefficient to silk and PGLA sutures. Moreover, CGG/ACNF suture with antibiosis and cytocompatibility exhibits better growth promotion of cells than silk suture, similar to PGLA suture in vitro. In addition, the stitching experiment of mice with the CGG/ACNF suture further confirms better healing properties and less inflammation in vivo than silk and PGLA sutures do. Hence, the CGG/ACNF suture with a simple preparation method and excellent application properties is promising in surgical operations., (© 2022 Wiley-VCH GmbH.)

The structure and dynamics of networks formed by rod-shaped particles can be indirectly investigated by measuring the diffusion of spherical tracer particles. This method was used to characterize cellulose nanofibril (CNF) networks in both dispersed and arrested states, the results of which were compared with coarse-grained Brownian dynamics simulations. At a CNF concentration of 0.2 wt% a transition was observed where, below this concentration tracer diffusion is governed by the increasing macroscopic viscosity of the dispersion. Above 0.2 wt%, the diffusion of small particles (20-40 nm) remains viscosity controlled, while particles (100-500 nm) become trapped in the CNF network. Sedimentation of silica microparticles (1-5 μm) in CNF dispersions was also determined, showing that sedimentation of larger particles is significantly affected by the presence of CNF. At concentrations of 0.2 wt%, the sedimentation velocity of 5 μm particles was reduced by 99 % compared to pure water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

The most common and abundant polymer in nature is the linear polysaccharide cellulose, but processing it requires a new approach since cellulose degrades before melting and does not dissolve in ordinary organic solvents. Cellulose aerogels are exceptionally porous (>90 %), have a high specific surface area, and have low bulk density (0.0085 mg/cm 3 ), making them suitable for a variety of sophisticated applications including but not limited to adsorbents. The production of materials with different qualities from the nanocellulose based aerogels is possible thanks to the ease with which other chemicals may be included into the structure of nanocellulose based aerogels; despite processing challenges, cellulose can nevertheless be formed into useful, value-added products using a variety of traditional and cutting-edge techniques. To improve the adsorption of these aerogels, rheology, 3-D printing, surface modification, employment of metal organic frameworks, freezing temperature, and freeze casting techniques were all investigated and included. In addition to exploring venues for creation of aerogels, their integration with CNC liquid crystal formation were also explored and examined to pursue "smart adsorbent aerogels". The objective of this endeavour is to provide a concise and in-depth evaluation of recent findings about the conception and understanding of nanocellulose aerogel employing a variety of technologies and examination of intricacies involved in enhancing adsorption properties of these aerogels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Processing cellulose nanofibril (CNF) hydrogels with a high concentration is a solution to reduce logistics costs and drying energy and to produce CNF-based materials with good dimensional stability. However, the rheology of concentrated and highly concentrated CNF hydrogels is poorly understood due to the difficulties to characterise them using standard shear rheometers. In this study, enzymatic CNF hydrogels in the concentrated and highly concentrated regimes (3-13.6 wt%) were subjected to lubricated compression at various strain rates. At low strains, compression curves exhibited a linear regime. At higher strains and low strain rates, a heterogeneous and marked hardening of stress levels was observed and accompanied with a two-phase flow with significant fluid segregation and network consolidation. At high strain rates, a homogeneous and incompressible one-phase plateau-like regime progressively established. In this regime, a yield stress was measured and compared with literature data, showing a good agreement with them., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Generally, the thermal conductivity (TC) of composite based on cellulose nanofibrils (CNF) is improved by adding thermal conductive filler, which inevitably leads to the loss of its mechanical properties. In this work, it is the first to simultaneously improve the toughness and TC of CNF/boron nitride nanosheets (BNNS) composite from the perspective of thermal conductive filler addition and CNF crystal change. The hydrophilic-modified BNNSs were successfully prepared by xylose-assisted ball-milling prior to adding into CNF. Compared with that of CNF film (1.34 W/(m·K)), the in-plane TC of CNF/BNNS composite (12.68 W/(m·K)) increased significantly by 846 % with loading 30 % BNNS. Afterwards, both toughness (8.0 MJ·m -3 , increased ~250 %) and TC (14.7 W/(m·K), increased ~16 %) of CNF/BNNS composite were further enhanced significantly by mercerization with 12.5 % NaOH solution. The simultaneously improvement of toughness and TC is unprecedented in related studies, which contributes to the effective preparation of thermal management materials., Competing Interests: Declaration of competing interest The authors declare no competing interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Nanocellulose (NC), including cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial cellulose (BC), has attracted a great deal of attention as a green packaging material. NC can protect food from pathogen adhesion and can be degraded by microorganisms after being discarded. In this review, we introduce preparations of NC-based film, including layer by layer (LbL) assembly, electrospinning, coating, extrusion, casting, vacuum filtration, and immersion. We summarize the interaction between microorganisms and NC, and focused on the impact of NC on microbial adhesion to surfaces and the influence of microorganisms on degradation of NC-based film. We put forward the challenges of NC faces in packaging, such as hydrophobicity, antibacterial properties, and industrialization. We finally propose future perspectives of NC-based film as the packaging material., (Copyright © 2022. Published by Elsevier Ltd.)

Physically cross-linked collagen hydrogel is a desirable scaffold for tissue engineering applications especially where 3D cell encapsulation is considered. To overcome its shortcomings such as weak mechanical properties and also provide additional benefits, nanofiller reinforcement could be applied. This study was conducted to compare physical properties and cellular performance of physically cross-linked collagen hydrogel reinforced with cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs). Addition of both nanofillers drastically changed the hydrogel properties depending on the type and concentration. As a general trend, both CNCs and CNFs resulted in reduction in gelation time, enhancement in compressive strength, increase in swelling ratio, decrease in weight loss and improvement of injectability. The highest impact for CNCs was achieved when 5 % was applied, while the maximum impact for CNFs was observed for 3 % content (related to the collagen solid weight). By comparing two types of nanocellulose, CNCs showed higher impact on all properties. In-vitro cell compatibility with fibroblasts showed that CNFs did not adversely affected the viability and morphology of the cells while the CNCs improved cell viability and developed more elongated cell morphology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Three-dimensional multicellular spheroids (MCSs) are complex structure of cellular aggregates and cell-to-matrix interaction that emulates the in-vivo microenvironment. This research field has grown to develop and improve spheroid generation techniques. Here, we present a new platform for spheroid generation using Layer-by-Layer (LbL) technology. Layer-by-Layer (LbL) containing cellulose nanofibrils (CNF) assemble on a standard 96 well plate. Various bi-layer numbers, multiple cell seeding concentration, and two tumor cell lines (HEK 293 T, HCT 116) are utilized to generate and characterize spheroids. The number and proliferation of generated spheroids, the viability, and the response to the anti-cancer drug are examined. The spheroids are formed and proliferated on the LbL-CNF coated wells with no significant difference in connection to the number of LbL-CNF bi-layers; however, the number of formed spheroids correlates positively with the cell seeding concentration (122 ± 17) and (42 ± 8) for HCT 116 and HEK 293T respectively at 700 cells ml -1 . The spheroids proliferate progressively up to (309, 663) µm of HCT 116 and HEK 293T respectively on 5 bi-layers coated wells with maintaining viability. The (HCT 116) spheroids react to the anti-cancer drug. We demonstrate a new (LbL-CNF) coating strategy for spheroids generation, with high performance and efficiency to test anti-cancer drugs., (© 2022 The Authors. Macromolecular Bioscience published by Wiley-VCH GmbH.)

Phase change materials (PCM) have been increasingly used over the past decades in applications requiring thermal energy storage or maintaining temperature uniformity, in particular in the textile industry. Organic PCM is desired in temperature control, but it suffers from thermal leaking and unstable form during phase transition. Here, cellulose nanofibrils (CNFs) were used as emulsifiers to stabilize paraffin Pickering emulsion by ultrasonication. Results indicated uniform PCM emulsion particles of 4.2 ± 2.1 μm could be obtained using 0.8 wt% CNF suspension sonicated at 100%A and 7 mins with 2:8 paraffin to CNF ratio. The CNF-stabilized paraffin emulsion showed excellent long-term stability with unchanged particle size when stored at 45 °C for 28 days. In addition, differential scanning calorimetry (DSC) results showed high thermal stability after 51 heating-cooling cycles with high latent heat of 117.6 J/g. The CNF-stabilized paraffin emulsion can be facilely spray-coated onto fabric to prepare thermal regulating textile., (Copyright © 2022. Published by Elsevier Ltd.)

The potential applications of cellulose nanomaterials (CNMs) as food additives or in food packaging, present a possible source of human ingestion. While micron- and macro-scale cellulose products are classified as Generally Regarded As Safe, the safety of ingested nano-scale cellulose is largely unknown. Using fully differentiated Caco-2 cells, the perturbation of intestinal barrier function and cytotoxicity was investigated for four nanocellulose crystals (CNCs) and four nanocellulose fibrils (CNFs) following 24 h of exposure at 50 μg/mL. Scanning electron microscope showed some aggregation of both CNCs and CNFs. X-ray photoelectron spectroscopy analyses showed that carbon and oxygen were the main elements. The zeta-potential for CNMs formulated in cell culture medium showed a negative surface charge. Two CNMs increased cell membrane permeability and three CNMs decreased the cell metabolic activity. While three CNMs lead to cytotoxic responses, no changes in apparent permeability coefficient (P app ) for dextran or tight junction integrity were found. Our results show that three CNMs induce cytotoxicity in differentiated Caco-2 cells, demonstrating the need to understand the role of size and shape. The interaction between CNMs and the intestinal epithelium needs to be evaluated to understand potential intestinal barrier dysfunction and resulting health implications following CNM ingestion., (Copyright © 2022. Published by Elsevier Ltd.)

Mineral fillers hinder cellulosic fiber bonding and thus limit the increase of filler content in paper. Herein, precipitated calcium carbonate (PCC)/cellulose nanofibrils (CNF) composites were fabricated by a facile and efficient strategy, i.e., co-refining process (CRP). During this process, CNF and PCC were activated by mechanochemical effect and formed encapsulation structure by calcium ion coordination and hydrogen bonding. The encapsulation structure and H-bond/ionic coordination interactions not only endowed the composite with excellent size stability but also enhanced interfacial interaction between composite fillers and cellulosic fibers. Compare with the paper filled with only PCC, PCC + CNF mixture, the tensile index of the cellulosic paper containing PCC/CNF composite was increased by 44.48% and 12.14%, respectively. These results not only provide a facile and scalable approach to increase interaction between cellulosic fiber and mineral filler but also create more possibilities for special paper-based materials with requiring high content of inorganic materials., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Chemical modification in surface of cellulose nanofibrils CNFs (20 nm) from an endemic and non-significant value-added, Argentine bamboo, was developed. The modification in the CNFs was carried out with three simple routes using a low molecular weight polylactic acid synthesized in our laboratory (PLA1). The first step comprises of protection of the hydroxyl groups of PLA1 through a benzoylation (PLA1Bz). The next step consisted of the activation of carboxyl groups using thionyl chloride and the last reaction was the grafting of the modified PLA onto the CNFs (PLA1Bz-g-CNF). The covalently functionalization is confirmed by spectroscopically techniques as well as PLA1Bz-g-CNFs were characterized by thermal analyses. The PLA1Bz-g-CNFs were taken up such as nanocharges to improve properties of compatibilization and changing surface properties in films based on PLA. The comparison between the films with PLA1Bz-g-CNFs with respect to the physic mixture of the components (PLA1Bz/CNF), shows an improvement in the thermal, mechanical, and surface properties of the material, particularly when 5% of PLA1Bz-g-CNFs was added. The dispersive (γS D) component of film is increased in 36.1 mN/m respect to 29.3 mN/m from the films obtained with the physic mixture nanofibrils without modification and a plasticizing effect was noticed in the final material., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Polyoxometalate (POM) presents great potential in oxidative desulfurization (ODS) reaction. However, the high dissolubility of POM in common solvents makes it difficult to recycle. Besides, the small specific surface area of POM also limits the interaction between them and the substrate. Depositing polyoxometalates onto three-dimensional (3D) network structured materials could largely expand the application of POM. Here, the surfaces of cellulose nanofibrils (CNFs) were modified with very few (3-Aminopropyl) trimethoxysilane (APTS) to endow positive charges on the surfaces of CNFs, and then phosphotungstic acid (PTA) was loaded to obtain the aerogel A-CNF/PTA as the ODS catalyst. FT-IR indicated the successful deposition of PTA onto aminosilane modified CNF surfaces. UV-VIS further suggested the stability of PTA in the aerogels. BET and SEM results suggested the increased specific surface area and the relatively uniform 3D network structure of the prepared aerogels. TGA analysis indicated that the thermal stability of the aerogel A-CNF/PTA50% was a little higher than that of the pure CNF aerogel. Most importantly, the aerogel A-CNF/PTA50% showed good catalytic performance for ODS. Catalysis results showed that the substrate conversion rate of the aerogel A-CNF/PTA50% reached 100% within 120 min at room temperature. Even after five cycles, the substrate conversion rate of the aerogel A-CNF/PTA50% still reached 91.2% during the dynamic catalytic process. This work provides a scalable and facile way to stably deposit POM onto 3D structured materials.

Background: Cellulose nanofibrils (CNFs) have emerged as a sustainable and environmentally friendly option for a broad range of applications. The fibrous nature and high biopersistence of CNFs call for a thorough toxicity assessment, but it is presently unclear which physico-chemical properties could play a role in determining the potential toxic response to CNF. Here, we assessed whether surface composition and size could modulate the genotoxicity of CNFs in human bronchial epithelial BEAS-2B cells. We examined three size fractions (fine, medium and coarse) of four CNFs with different surface chemistry: unmodified (U-CNF) and functionalized with 2,2,6,6-tetramethyl-piperidin-1-oxyl (TEMPO) (T-CNF), carboxymethyl (C-CNF) and epoxypropyltrimethylammonium chloride (EPTMAC) (E-CNF). In addition, the source fibre was also evaluated as a non-nanosized material., Results: The presence of the surface charged groups in the functionalized CNF samples resulted in higher amounts of individual nanofibrils and less aggregation compared with the U-CNF. T-CNF was the most homogenous, in agreement with its high surface group density. However, the colloidal stability of all the CNF samples dropped when dispersed in cell culture medium, especially in the case of T-CNF. CNF was internalized by a minority of BEAS-2B cells. No remarkable cytotoxic effects were induced by any of the cellulosic materials. All cellulosic materials, except the medium fraction of U-CNF, induced a dose-dependent intracellular formation of reactive oxygen species (ROS). The fine fraction of E-CNF, which induced DNA damage (measured by the comet assay) and chromosome damage (measured by the micronucleus assay), and the coarse fraction of C-CNF, which produced chromosome damage, also showed the most effective induction of ROS in their respective size fractions., Conclusions: Surface chemistry and size modulate the in vitro intracellular ROS formation and the induction of genotoxic effects by fibrillated celluloses. One cationic (fine E-CNF) and one anionic (coarse C-CNF) CNF showed primary genotoxic effects, possibly partly through ROS generation. However, the conclusions cannot be generalized to all types of CNFs, as the synthesis process and the dispersion method used for testing affect their physico-chemical properties and, hence, their toxic effects., (© 2022. The Author(s).)

Traditional adhesives with strong adhesion are widely applied in the fields of wood, building, and electronics. However, the synthesis and usage of commercial adhesives are not eco-friendly, which are harmful to human health and to the environment. In this study, a green cellulose nanofibrils/poly(hydroxyethyl methacrylate- co -dopamine methacrylamide) (CNFs/P(HEMA- co -DMA)) adhesive with excellent biocompatibility and strong bonding strength has been fabricated. P(HEMA- co -DMA) with a catechol content of 7.1 mol % was synthesized using dopamine methacrylamide and hydroxyethyl methacrylate. The CNFs/P(HEMA- co -DMA) adhesive was generated by cross-linking P(HEMA- co -DMA) solution using cellulose nanofibrils (CNFs). Strong adhesion was realized on various substrates, with a maximum lap shear strength of 5.50 MPa on steel. The NIH 3T3 cells test demonstrated that the adhesive possessed excellent biocompatibility. The green catechol-containing CNFs-cross-linked adhesive has promising potential for applications in medicine, electronic, food packaging, and engineering.

Creating a low-cost, highly efficient, and recyclable superabsorbent for spilled-oil cleanup is of great significance but remains a big challenge. Herein, we report a facile strategy to produce economic, environmentally friendly, and reusable foam from agricultural waste kapok fibers. These kapok-derived cellulose nanofibrils foams (KNFs) demonstrate a hierarchically porous structure at micro-level with ultra-low density (2.7 mg·cm -3 ). The superhydrophobic KNFs (150.5°) show outstanding oil absorption (126.8-320.4 g·g -1 ) and oil-water separation performance. Notably, a facile approach is designed to reuse KNFs easily by a homemade oil release system. The release behavior of the KNFs is quantitatively analyzed and confirmed by the Rigter-Peppas model, indicating that the oil release followed the Fickian diffusion. The KNFs exhibit desirable reusability, and can be recycled for at least 50 times while keeping excellent oil absorption, and release performance. These advantages prove that the KNF is a desirable substitute for spilled-oil treatment., (Copyright © 2021. Published by Elsevier Ltd.)

This study was designed to improve the stability of medium internal phase emulsion by adjusting the electrostatic interaction between gelatin (GLT) and TEMPO-oxidized bacterial cellulose nanofibrils (TOBC). The influences of polysaccharide-protein ratio (1:10, 1:5, and 1:2.5) and pH (3.0, 4.7, 7.0, and 11.0) on the emulsion properties were investigated. The droplet size of TOBC/GLT-stabilized emulsion was increased with the TOBC proportion increasing at pH 3.0-11.0. Additionally, emulsion had a larger droplet size at pH 4.7 (the electrical equivalence point pH of mixtures). However, the addition of TOBC significantly improved the emulsion stability. The emulsions prepared with TOBC/GLT mixtures (mixing ratio of 1:2.5) at pH 3.0-7.0 were stable without creaming during the storage. It was because the formation of nanofibrils network impeded the droplet mobility, and the emulsion viscosity and viscoelastic modulus were increased with the addition of TOBC. These findings were meaningful to modulate the physical properties of emulsions., (Copyright © 2021. Published by Elsevier Ltd.)

Cellulose nanofibril (CNF) paper has various applications due to its unique advantages. Herein, we present the intrinsic mechanical properties of CNF papers, along with the preparation and properties of nanoparticle-reinforced CNF composite papers. The literature on CNF papers reveals a strong correlation between the intrafibrillar network structure and the resulting mechanical properties. This correlation is found to hold for all primary factors affecting mechanical properties, indicating that the performance of CNF materials depends directly on and can be tailored by controlling the intrafibrillar network of the system. The parameters that influence the mechanical properties of CNF papers were critically reviewed. Moreover, the effect on the mechanical properties by adding nanofillers to CNF papers to produce multifunctional composite products was discussed. We concluded this article with future perspectives and possible developments in CNFs and their bionanocomposite papers., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Plant-based hydrogels have attracted great attention in biomedical fields since they are biocompatible and based on natural, sustainable, cost-effective, and widely accessible sources. Here, we introduced new viscoelastic bio-inks composed of quince seed mucilage and cellulose nanofibrils (QSM/CNF) easily extruded into 3D lattice structures through direct ink writing in ambient conditions. The QSM/CNF inks enabled precise control on printing fidelity where CNF endowed objects with shape stability after freeze-drying and with suitable porosity, water uptake capacity, and mechanical strength. The compressive and elastic moduli of samples produced at the highest CNF content were both increased by ~100% (from 5.1 ± 0.2 kPa and 32 ± 1 kPa to 10.7 ± 0.5 and 64 ± 2 kPa, respectively). These values ideally matched those reported for soft tissues; accordingly, the cell compatibility of the printed samples was evaluated against HepG2 cells (human liver cancer). The results confirmed the 3D hydrogels as being non-cytotoxic and suitable to support attachment, survival, and proliferation of the cells. All in all, the newly developed inks allowed sustainable 3D bio-hydrogels fitting the requirements as scaffolds for soft tissue engineering., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

To achieve the balance on economy and ecology, it is indispensable to explore the greener and more inexpensive method for the production of cellulose nanofibrils (CNFs). Herein, a deep eutectic solvent (DES) system based on choline chloride (ChCl) and ethylene glycol (EG) was employed as the swollen solvent, combining with screw extrusion and permeant, to fabricate unmodified CNFs with high yield and thermal stability. The proposed method in this work was simple, convenient, and industrially viable. The hydrous DESs were applied in the process of CNFs preparation and dispersion to reduce the cost and viscosity of DES. To reveal the principle of CNFs preparation, the impact of sulfuric acid and water content of DES system on the chemical, physical, morphological, thermal, and dispersive properties of CNFs was systematically studied. Properties of the dispersed solvents were characterized by solvatochromic parameters and viscosity parameters to evaluate the potential influence on the preparation and dispersion of CNFs. In general, this work would play valuable guidance in realizing the preparation and dispersion of CNFs via a versatile DES solvent system, thus endowing cellulose materials high-value utilization., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In this study, we fabricate physically dual-crosslinked cellulose-based hydrogels by varying coordination bonding effects with the addition of either divalent or trivalent metal cations. The first crosslinked network is created by metal-carboxylate coordination bonds between the cellulose nanofibrils that have abundant carboxyl groups and the metal cations. The second crosslinked network is formed by the reaction of tetra-functional borate ion complex and the hydroxyl groups in polyvinyl alcohol. These physically dual-crosslinked networks are strongly interwoven by non-sacrificial hydrogen bonds, this dual-crosslinked network leads to enhanced recovery characteristics in the resulting hydrogels. We use three interval thixotropic testing to investigate the deformation and recovery behaviors of the hydrogels and plot their structural deformation parameters in phase diagrams to understand the underlying complexity of energy dissipation and viscoelastic dynamics of the dual-crosslinked hydrogels., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

We proposed a simple method to process hydrogels containing polyvinyl alcohol and cellulose nanofibrils (PVA/CNF) to prepare volumetric architectures by direct ink writing (DIW). The presence of CNF in the aqueous PVA suspensions conferred rheology profiles that were suitable for extrusion and solidification in pre-designed shapes. The viscoelastic behavior of the hybrid inks enabled precise control on processability and shape retention, for instance, as demonstrated in multilayered lattice structures of high fidelity. After lyophilization, the obtained 3D-printed hydrogels presented a very high porosity, with open and interconnected pores, allowing a high-water uptake capacity (up to 1600%). The mechanical strength of the composite 3D-printed materials matched those of soft tissues, opening opportunities for skin applications. As such, drug-loaded samples revealed a controlled and efficient delivery of an antioxidant (ascorbic acid) in PBS buffer media at 23 °C (~80% for 8 h). Altogether, PVA/CNF hydrogels were introduced as suitable precursors of 3D-lattice geometries with excellent physical and mechanical characteristics., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

This work demonstrated a facile and sustainable approach to functionalize cellulose nanopaper (CNP) by impregnation of chitosan (CS) and the followed halogenation. It was found that the tensile strength of the functionalized CNP (CNP/CS-Cl) was enhanced by 38.3% and 512.6% at dry and wet conditions, respectively. Meanwhile, the total transmittance (at 550 nm) of CNP/CS-Cl was increased from 75% of pure CNP to 85%, with 35% decrease in optical haze. Moreover, the CNP/CS-Cl exhibited significant enhancement in barrier properties. Importantly, part of the amino groups on CS were transformed into N-halamines during the halogenation process, which endowed the CNP/CS-Cl with excellent antibacterial performance against both S. aureus and E. coli with 100% bacterial reduction after 10 min of contact. Thus, this work provides a simple and efficient approach to functionalize CNP with water resistance, high transparency, excellent antibacterial and barrier properties, which will expand the potential applications of CNP., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The combination of good stability, biocompatibility, and high mechanical strength is attractive for bio-related material applications, but it remains challenging to simultaneously achieve these properties in a single, ionically conductive material. Here a "wood" ionic cable, made of aligned wood nanofibrils, demonstrating a combination of biocompatibility, high mechanical strength, high ionic conductivity, and excellent stability is reported. The wood ionic cable possesses excellent flexibility and exhibits high tensile strength up to 260 MPa (in the dry state) and ≈80 MPa (in the wet state). The nanochannels within the highly aligned cellulose nanofibrils and the presence of negative charges on the surfaces of these nanochannels, originating from the cellulose hydroxyl groups, provide new opportunities for ion regulation at low salt concentrations. Ion regulation in turn enables the wood ionic cable to have unique nanofluidic ionic behaviors. The Na + ion conductivity of the wood ionic cable can reach up to ≈1.5 × 10 -4 S cm -1 at low Na + ion concentration (1.0 × 10 -5 mol L -1 ), which is an order of magnitude higher than that of bulk NaCl solution at the same concentration. The scalable, biocompatible wood ionic cable enables novel ionic device designs for potential ion-regulation applications., (© 2021 Wiley-VCH GmbH.)

In this study, cellulose nanofibrils (CNFs) were modified by catalyzed lactic acid esterification in an aqueous medium with SnCl 2 as a catalyst. Films were made from unmodified and lactic acid-modified CNF without a polymer matrix to evaluate the effectiveness of the modification. Ungrafted and lactic acid-grafted CNF was also compounded with poly(lactic acid) (PLA) to produce composites. Mechanical, water absorption, and barrier properties were evaluated for ungrafted CNF, lactic acid-grafted CNF films, and PLA/CNF composites to ascertain the effect of lactic acid modification on the properties of the films and nanocomposites. FTIR spectra of the modified CNF revealed the presence of carbonyl peaks at 1720 cm -1 , suggesting that the esterification reaction was successful. Modification of CNF with LA improved the tensile modulus of the produced films but the tensile strength and elongation decreased. Additionally, films made from modified CNF had lower water absorption, as well as water vapor and oxygen permeability, relative to their counterparts with unmodified CNFs. The mechanical properties of PLA/CNF composites made from lactic acid-grafted CNFs did not significantly change with respect to the ungrafted CNF. However, the addition of lactic acid-grafted CNF to PLA improved the water vapor permeability relative to composites containing ungrafted CNF. Therefore, the esterification of CNFs in an aqueous medium may provide an environmentally benign way of modifying the surface chemistry of CNFs to improve the barrier properties of CNF films and PLA/CNF composites.

As a type of sustainable nanomaterials, nanocellulose has drawn increasing attention over the last two decades due to its great potential in diverse value-added applications such as electronics, sensors, energy storage, packaging, pharmaceuticals, biomedicine, and functional food. Sourcing nanocellulose from lignocellulose is commonly accomplished via the use of mineral acids, oxidizers, enzymes, and/or intensive mechanical energy. Yet, the economic and environmental concerns associated with these conventional isolation techniques pose major obstacles for commercialization. Considerable progress has been achieved in the last few years in developing sustainable nanocellulose isolation technologies involving organic acid/anhydride, Lewis acid, solid acid, ionic liquid, and deep eutectic solvent. This paper provides a comprehensive review of these alternatives with regard to general procedures and key advantages. Important knowledge gaps, including total biomass utilization, complete life cycle analysis, and health/safety, require urgently bridging in order to develop economically competitive and operationally feasible nanocellulose isolation technology for commercialization., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Developing green and simple methods for the preparation of cellulose nanofibrils (CNFs) is of great significance. Herein, a green deep eutectic solvent (DES) system based on choline chloride (ChCl) and citric acid (CA) is employed to pretreat cellulose fibers for the preparation of CNFs. The effect of the pretreatment temperature on the chemo-physical properties of the CNFs is comprehensively investigated. A high CNFs yield of up to 84.19% can be achieved under optimized conditions. The optimal CNFs show a narrow diameter distribution and length up to several microns, high crystallinity and thermal stability, as well as excellent dispersibility in water. Furthermore, semi-transparent and flexible cellulose nanopaper (CNP) was fabricated through a facile vacuum filtration process. The optimal CNP shows high tensile strength (175.15 MPa) and toughness (7.51 MJ/m 3 ). Therefore, this work provides a sustainable and facile approach to fabricate CNFs and CNP, which can be potentially used for various high-tech applications., (Copyright © 2021. Published by Elsevier Ltd.)

Simultaneously achieving good mechanical properties and high tolerance to hot and cold environments in hydrogel materials remains a challenge. In this work, ethylene glycol (EG) and cellulose nanofibrils (CNFs) were introduced into chitosan/poly(acrylamide-acrylic acid) double-network hydrogels to improve their toughness and tolerance to hot and cold environments. The effect of EG and CNFs on the properties of the hydrogels was studied respectively. EG increases the tolerance of the hydrogel to hot and cold environments. However, EG had a negative effect on the mechanical properties of hydrogels. In addition, CNFs substantially enhanced the strength and toughness of the chitosan/poly(acrylamide-acrylic acid)/EG organohydrogels. Finally, with the cooperative action of EG and CNFs, high-strength and tough organohydrogels (tensile strength = 0.71 MPa, elongation at break = 787.2%) with a high tolerance to hot and cold environments (-23 °C to 60 °C) were obtained. Further, EG enabled the organohydrogel to revert to its original state after drying at 60 °C. This paper provides a new route to prepare high-strength and tough organohydrogels with a high tolerance to hot and cold environments., (Copyright © 2021 Elsevier B.V. All rights reserved.)