TOCNF酯化反应的两类温度：80–90℃温和酯化/界面改性与120–130℃较充分酯化/交联

In this research, we develop a method to create biodegradable food packaging films. Initially, TEMPO-oxidized cellulose nanofiber (TOCNF) undergoes sonication to produce well-dispersed single-strain nanofibers. These nanofibers are then blended with waterborne polyurethane (WPU) to enhance their extensibility. To further enhance compatibility between these two components, a non-ionic surfactant, Tween 80, is introduced into the TOCNF/WPU mixture to improve the dispersion of the WPU within the blend. The addition of Tween 80 significantly increases the transparency of the resulting film (Transmittance: 89.4 %, Haze: 2.2 %). Furthermore, the incorporation of the surfactant effectively reduces the formation of wrinkles and cracks during the film drying process, preventing adverse impacts on the film's barrier properties. The thin film further undergoes esterification crosslinking with citric acid to remove its hydrophilic groups for better water vapor barrier properties. The resulting bio-based packaging film exhibits remarkable transparency, strong biodegradability, and superior gas-barrier properties (water vapor and oxygen) compared to commonly used food packaging.

In this study, a brand-new, easy, and environmentally friendly approach for chemically functionalizing 2,2,6,6-tetramethylpiperidinyloxyl radical (TEMPO)-oxidized cellulose nanofiber (TOCNF) to produce modified cellulose nanofiber (octadecylamine-citric acid-CNF) was proposed. Effects of octadecylamine (ODA)/TOCNF mass ratio on the chemical structure, morphology, surface hydrophobicity and oleophobicity were studied. According to Fourier transform infrared spectroscopy (FTIR) analysis, ODA was successfully grafted onto the TOCNF by simple citric acid (CA) esterification and amidation reactions. Scanning electron microscopy (SEM) showed that a new rough structure was formed on the ODA-CA-CNF surface. The water contact angle (WCA) and the castor oil contact angle (OCA) of the ODA-CA-CNF reached 139.6° and 130.6°, respectively. The high-grafting-amount ODA-CA-CNF was sprayed onto paper, and the OCA reached 118.4°, which indicated good oil-resistance performance. The low-grafting-amount ODA-CNF was applied in a pH-responsive indicator film, exhibiting a colour change in response to the pH level, which can be applied in smart food packaging. The ODA-CA-CNF with excellent water/oil-resistance properties and fluorine-free properties can replace petrochemical materials and can be used in the fields of fluorine-free oil-proof paper.

In this paper, based on the TEMPO oxidated Cellulose Nanofiber (TOCNF)/ɛ-poly-l-lysine (ɛ-PL) cross-linking network and citric acid as the cross-linking agent, aerogel material was designed. Citric acid (CA) can be used as a multifunctional cross-linking agent with TOCNF esterification cross-linking, and with TOCNF and ɛ-PL hydrogen bond cross-linking, but also as a reinforcing agent to improve mechanical and antibacterial properties. When the ɛ-PL content reached 0.8%, the tensile strength of the aerogel increased from 12.03 MPa to 26.44 MPa, while the elongation at break decreased to 29.33%. As the amount of ɛ-PL increased, the thermal decomposition temperature of aerogel rose to 215 °C. Aerogels had a high antibacterial efficiency (above 99.9%). After 28 days, aerogels can be biodegraded in the soil. More importantly, the aerogel had a hemolysis rate of less than 5%, indicating that the prepared degradable cellulose aerogel was a material with good blood compatibility. It had huge application potential in medical environment and food packaging.

Deep eutectic solvents (DESs), as emerging green solvents, provide a new opportunity for the biorefinement of biomass, component extraction, and cellulose nanofibrillation. Herein, different carboxylic acid-based DESs were applied for preparation of cellulose nanofibers (CNFs) from cellulose raw materials accompanied by simultaneous esterification modifications of CNFs. The results showed that pretreatment of DESs combined with mechanical treatment can swell and esterify the cellulose materials, producing CNFs with widths less than 100 nm. The DES pretreatment temperature played important roles in the esterification modifications and nanofibrillation of cellulose. The esterification modifications of cellulose prevented the over-hydrolysis and dissolution of cellulose during the DES pretreatment, guaranteeing CNFs with high yields of 72 %-88 % and maintaining the cellulose I crystal structure. Moreover, the esterified CNFs were used as a reinforcement to prepare CNF-strengthened polylactic acid (PLA) composites. The surface esterification of the CNFs improved their dispersibility and interfacial compatibility with PLA, thereby achieving the mechanical enhancement of CNF/PLA composites.

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PM2.5, which can carry many bacteria, poses a serious threat to health when inhaled. Therefore, developing porous materials with efficient filtration and antibacterial properties is essential for preventing the invasion of PM2.5 on respiratory health. In this study, we designed a multifunctional sponge filter through the synergistic integration of TEMPO-oxidized cellulose nanofibrils (TCNF), chitosan (CS), graphene oxide (GO), and lignin hybrid particles. A robust three-dimensional network was constructed via amide cross-linking between TCNF and CS, endowing the sponge with exceptional mechanical stability. GO enhances the PM2.5 interception efficiency through electrostatic adsorption. Additionally, we introduce lignin nanoparticles (LNP) as carriers for growing zinc oxide (ZnO), forming organic-inorganic hybrid particles (LNP@ZnO). This approach minimizes the negative impact of ZnO on the mechanical properties of the sponge while enhancing antibacterial performance. The resulting sponge filter demonstrates high PM2.5 filtration efficiency (99.14 %) with low pressure drop (38 Pa), excellent antibacterial properties against E. coli (92.63 %) and S. aureus (89.05 %), and outstanding flame-retardant properties (LOI value of 27.1 %). This study addresses the limitations of existing systems by minimizing the trade-off between antibacterial performance and mechanical strength, offering a novel approach for the design of advanced air filtration materials.

We prepared 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized samples from never-dried Japanese cedar (JC) holocellulose, JC-callus, and bacterial cellulose (BC). The original never-dried samples and their TEMPO-oxidized products were characterized by neutral sugar composition analysis. TEMPO-oxidized cellulose nanofibrils (TEMPO-CNFs) were prepared from the TEMPO-oxidized samples by ultrasonication in water. The carboxy groups in TEMPO-CNFs were position-selectively esterified with 9-anthryl diazomethane (ADAM) to prepare TEMPO-CNF-COOCH2-C14H9 samples, which had UV absorption peak at 365 nm. The mass-average degree of polymerization (DPw) values of 1% lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) solutions of the original samples were determined by size-exclusion chromatography in combination with multi-angle laser-light scattering, ultraviolet absorption, and refractive index detection (SEC/MALLS/UV/RI), and were 5490, 2660, and 2380 for the JC holocellulose, JC-callus, and BC samples, respectively. The TEMPO-CNF-COOCH2-C14H9 sample solutions in 1% LiCl/DMAc were analyzed by SEC/MALLS/UV/RI to obtain SEC elution patterns. The patterns corresponded to the molar mass and carboxy group distributions of the samples, which were detected by RI and UV absorption of anthryl groups, respectively. The carboxy groups existed in the entire molar mass distribution regions of all the TEMPO-CNF samples, although their lower molar mass regions contained higher carboxy group densities. The obtained results indicate that random depolymerization occurred on the cellulose microfibril surfaces at the initial stage of TEMPO-catalyzed oxidation and/or ultrasonication in water. This depolymerization mechanism can explain all the obtained SEC-elution patterns of the TEMPO-CNFs, without considering the presence of periodically disordered regions in the cellulose microfibrils of the never-dried cellulose samples.

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The active hydroxyl group of cellulose plays a crucial role in regulating the microstructure of cellulose-derived hard carbon, which ultimately affects its sodium storage capacity. Through small-angle X-ray scattering (SAXS) and X-ray atomic pair distribution function (PDF) analysis, we proved that modification of cellulose by esterification crosslinking can introduce more closed pores into the carbonized hard carbon, which is beneficial for promoting sodium ion storage. Our results demonstrate that by optimizing the conditions used for esterification cross-linking modification, the sodium storage capacity of cellulose-derived hard carbon could be increased from 254 to 348 mAh g−1, with an increase in plateau capacity from 140 to 230 mAh g−1. This study makes a significant contribution towards establishing industrial applications for cellulose-derived hard carbon.

Resource depletion, waste management, and climate change drives innovation towards bioplastics. Among the renewable cellulose derivatives, hydroxypropyl cellulose (HPC) stands out for its biocompatibility, ease of processing, rheological tunability, and unique ability to form cholesteric mesophases at high concentrations. However, its water solubility has limited its use in advanced applications such as packaging, 3D printing, and smart labeling. To date, efforts to produce water-resistant HPC relied on solvent-based and catalyst-driven crosslinking approaches, which undermine its environmental benefits. Herein, we hypothesize that HPC can be effectively crosslinked under solvent-free conditions to produce biodegradable plastics. In the manuscript, we report a simple, one-step, solvent- and catalyst-free method to crosslink HPC using glutaric anhydride (GAn), combining high-shear mixing and heat-pressing. The resulting GAn@HPC material is water-insoluble, optically transparent, and mechanically tunable. Remarkably, upon rehydration and drying, the crosslinked polymer forms a cholesteric layered structure, demonstrating the potential to form structurally colored, crosslinked bioplastics with further tuning of cross-linking density. This scalable and sustainable method significantly enhances the functional potential of HPC while aligning with green chemistry principles. Our work contributes to advancing eco-friendly materials and positions crosslinked HPC as a promising alternative in sectors demanding both functionality and sustainability.

The enhanced mechanical durability of sprayed nanocellulose coatings at the macroscopic level is primarily required to promote their application in demanding industrial applications with frequently exposed surfaces. In this study, different coating configurations are designed by spraying aqueous cellulose nanofiber (CNF) suspensions in combination with boric acid (BA) as an internal crosslinker and polydopamine (PDA) as an adhesive interlayer onto glass substrates. Multilayer coatings (CNF/BA) or mixed-layer coatings (CNF + BA) with various concentrations of BA and numbers of sprayed layers are evaluated for maximized mechanical performance based on tape tests, rub tests, cross-cut tests, and scratching tests. Good adhesive strength was realized with an interlayer of PDA/BA (high-concentration BA = 10 mM). The highest cohesive strength was observed for a mixed CNF + BA coating (high-concentration BA = 10 mM) with a scratch resistance of 9 N, and a multilayer CNF/BA coating (gradient layers with ultra-high BA concentration = 100 mM) with a scratch resistance of 8 N. The coatings with the highest density did not uniquely introduce the best mechanical resistance when comparing CNF/BA and CNF + BA coatings, as the formation of BA crystals in multilayer coatings might negatively affect the mechanical properties through embrittlement. Alternatively, the mixed CNF + BA coatings with high BA concentrations provide high density and the best mechanical resistance. The favorable crosslinking corresponds to stabilized water contact angles and reduced spreading of the water as a function of time, while a decrease in coating density causes a reduction in transparency. The chemical interactions between CNF and BA are illustrated by infrared spectroscopy, confirming a reduction in free hydroxyl groups upon crosslinking.

The potential applications of cellulose nanofibril-based foam materials can be expanded by their enhanced water durability. This study proposes two crosslinking methods to improve the water durability of the oven-dried carboxymethylated cellulose nanofibril (CMCNF) foam. The first method involves the addition of a crosslinker, polyamideamine epichlorohydrin. The second method is the self-crosslinking of CMCNFs via heat treatment at 140 °C for less than an hour, which is a simple way to crosslink CMCNF-based materials. Both crosslinking methods resulted in excellent water durability and wet resilience of the foams, which also exhibited high water absorbency. Furthermore, neither method affected the structural nor mechanical properties of the oven-dried CMCNF foams. In particular, self-crosslinking by heat treatment proved to be as effective as using a crosslinking agent. Compared to the freeze-dried foam, the oven-dried foam exhibited slower methylene blue (MB) dye adsorption but a higher maximum adsorption capacity (238-250 mg/g), attributed to the closed pore structure and a larger specific surface area. In addition, the isotherm and reusability of the foam for MB adsorption were investigated. These crosslinking processes expanded the potential use of oven-dried CMCNF foams as adsorbents for cationic dyes.

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Abstract Cellulose nanofibrils (CNFs) are versatile materials, but their sensitivity to humidity affects performance. Esterification with fatty acids enhances the hydrophobicity of CNF films. This study compared gas- and liquid-phase esterification using three fatty acid chlorides at different dosages. Gas-phase esterification minimally affected cellulose crystallinity, maintaining a crystallinity index exceeding 55.8%, whereas liquid-phase esterification significantly reduced crystallinity. Gas-phase esterification achieved hydrophobicity (water contact angle >100°) with less fatty acid chlorides (0.50 eq/OH) compared to liquid-phase esterification (1.00 eq/OH). Tensile strength significantly dropped in the liquid phase (68.4–6 MPa) and up to an 8-fold decrease in the elastic modulus. Conversely, gas-phase esterification maintained tensile strength over 40 MPa, and elastic modulus increased by a minimum of 2.5 times. However, gas-phase esterification resulted in a 5-fold reduction in elongation at break (%). Thermogravimetric analysis indicated a high T max of 362°C for liquid-phase esterified samples and a substantial 24.9% residual weight for gas-phase esterified samples.

Cellulose nanofibril (CNF)-based hydrogels, owing to their sustainability, biocompatibility, and versatile mechanical properties, are promising for biomedical applications. This review analyzes the recent advances and biomedical applications of CNF hydrogels. CNF hydrogels can be prepared via physical and chemical crosslinking. Physical crosslinking involves surface charge density control, pH manipulation, and flow-based processing to generate stable networks, whereas chemical crosslinking employs agents such as epichlorohydrin and citric acid to form permanent covalent bonds. These approaches enable precise control over hydrogel properties, including mechanical strength, porosity, and stimuli responsiveness. CNF hydrogels are particularly promising in drug delivery systems and tissue engineering. CNFs as drug delivery vehicles offer enhanced bioavailability and drug loading capacity owing to their open pore structure and large surface area. Recent developments in stimuli-responsive and injectable CNF hydrogels have enabled controlled drug release and improved targeting capabilities. Moreover, CNF hydrogels serve as effective scaffolds for cell growth and tissue regeneration, with applications in cartilage engineering and wound healing. Integrating CNF hydrogels with 3D bioprinting technology has generated complex tissue structures. However, several challenges remain, including the need for the standardization of toxicology assessments, optimization of large-scale production processes, and development of sophisticated control mechanisms for drug delivery. Future research should advance manufacturing technologies, improve long-term stability, and develop standardized testing protocols for regulatory compliance.

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The underlying mechanism related to freezing-induced crosslinking of aldehyde-containing cellulose nanofibrils (CNFs) has been investigated, and the critical parameters behind this process have bee ...

Polyvinyl alcohol (PVA) has been extensively explored for its excellent film‐forming properties. However, its poor water resistance has limited practical applications. Crosslinking, a common method that enhances the water resistance, mechanical properties, and thermal stability of PVA films, is often employed. Although conventional hot‐air crosslinking can improve performance, it suffers from long processing times and high energy consumption. This study introduces infrared (IR) radiation instead of hot‐air heating to achieve ultra‐rapid crosslinking of PVA/cellulose nanocrystals (CNC) composites with poly (maleic anhydride) (PMA). Compared to hot‐air treatment, which requires 7200 s, IR treatment significantly enhances crosslinking efficiency, reducing the composite film's swelling rate by approximately 20% in just 120 s. FT‐IR analysis confirms that IR radiation promotes a more complete esterification crosslinking reaction. The IR‐treated composite film exhibited the best performance: water vapor transmission rate decreased from 1.447 g·m −2 ·d −1 (without heat treatment) to (0.175 g·m −2 ·d −1 ). The tensile strength of the composite film reached 47.18 MPa, significantly higher than the 39.03 MPa achieved with hot‐air treatment, and the strength retention rate remained as high as 92% at 50% relative humidity, along with superior thermal stability. This study provides a rapid, energy‐efficient new strategy for the efficient preparation of high‐performance PVA‐based composite films.

This study developed biodegradable carboxymethyl cellulose (CMC) films crosslinked with citric acid (CA) and X-ray irradiation as sustainable packaging alternatives to reduce plastic use. CMC/CA films were subjected to three doses of X-ray irradiation at two energy levels. CMC/CA films exposed to 10 kGy at 350 kV exhibited a significant three-fold reduction in water solubility compared to non-irradiated films, while also lowering water vapor and oxygen permeability without affecting mechanical strength (p ≤ 0.05). FTIR analysis confirmed the esterification between CMC and CA, which reduced the film hydrophilicity. Onion peel extract (OPE) was added as a bioactive compound to provide antifungal properties. Release studies showed reduced OPE diffusion in irradiated films, with lower release rate constant (kkp) values. The in situ test on cheese inoculated with Penicillium commune showed that the irradiated bioactive films prolonged shelf life, reducing fungal counts to log 2.3 CFU/g after 18 days compared to log 5.7 CFU/g in control samples. Cheese wrapped with irradiated bioactive films had weight loss from 1.05 to 9.37%, whereas uncovered samples exhibited the highest weight loss (2.07 to 15.07%). Overall, irradiation-assisted crosslinking and OPE incorporation improved film functionality, offering a sustainable and effective packaging solution for cheese preservation within a circular economy framework.

The development of sustainable hydrogels from renewable biomass has attracted increasing interest for environmental and agricultural applications. In this study, cellulose isolated from Pandanus tectorius leaves was utilized as a precursor for the synthesis of carboxymethyl cellulose (CMC), which was subsequently used to prepare hydrogels through ester-based crosslinking. A dual-network hydrogel structure was formed by blending CMC with hydroxyethyl cellulose (HEC), followed by esterification with citric (CA), fumaric (FA), and malic (MA) acids. Structural characterization using FTIR confirmed successful carboxymethylation and ester crosslinking within the polymer network, while SEM revealed a porous morphology favorable for water diffusion. The synthesized hydrogels exhibited gel fractions of 67–89%, swelling ratios of 578–4163%, and maximum degradation temperatures of 311–428°C. The CMC/HEC-MA hydrogel at a 15% crosslinker concentration demonstrated the most balanced combination of swelling capacity, gel fraction, and thermal stability. Owing to their high water-retention capability, porous structure, and biodegradability, these hydrogels show strong potential as superabsorbent materials for soil moisture conservation, controlled water release in agriculture, drought mitigation, and sustainable water management. These findings highlight the potential of biomass-derived hydrogels to support SDG 2 (Zero Hunger) by improving agricultural water retention, SDG 6 (Clean Water and Sanitation) by promoting efficient water management and treatment, and SDG 12 (Responsible Consumption and Production) by transforming renewable biomass resources into sustainable value-added materials.

Cellulose is the most abundant and renewable biopolymers on earth. The hydrophilic nature of cellulose endows cellulosic materials with good compatibility with polar matrices, but it also leads to their poor dispersion in non-polar matrices. Regulating the surface hydrophobicity of cellulosic materials via surface esterification can greatly extend their applications. However, the existing surface esterification methods for cellulosic materials are time-consuming and costly, which makes them less attractive for practical application. Here we found that when vinyl esters were used as esterifying agents, various alkalis can be used to catalyze the ultrafast surface esterification of cellulose materials in aqueous media at room temperature within seconds or minutes, which is highly attractive for the surface esterification of nanocellulose in suspension state. Surface acetylated cellulose nanofibers (ACNF) and surface acetylated cellulose nanocrystals (ACNC) with acetyl group content (Ac%) up to 10.7% and 6.5%, respectively, were successfully prepared within 5 min in aqueous diethylamine solution. Additionally, this method can also be used to achieve the rapid acetylation of phenol hydroxy group in aqueous media.

Hemp stalks are abundant renewable agricultural residues and promising feedstocks for nanocellulose, yet green and controllable pathways for converting their cellulose fraction into stable nanoscale materials remain limited. Here, an agricultural-residue-oriented hydrated deep eutectic solvent (H-DES)/oxidation synergistic deconstruction strategy was developed for hemp stalk, focusing on the temperature-governed balance among component fractionation, cellulose retention, carboxylation, and nanofibrillation. The treatment removed non-cellulosic components while introducing surface carboxyl functionality mainly via oxalic-acid mediated esterification, affording a cellulose-rich solid containing 90.6% cellulose, 5.3% hemicellulose, and 3.0% lignin. Unlike conventional 2,2,6,6-Tetramethylpiperidinooxy (TEMPO) oxidation, which selectively converts C6 primary hydroxyl groups into carboxylates under alkaline conditions, this H-DES/oxidation route integrates fractionation and surface esterification in one medium and preserves crystalline cellulose domains more effectively. Consequently, the obtained nanocellulose showed high colloidal stability, with a zeta potential of -61.1 mV, an average width of 4.6 nm, stability for more than 7 days, and superior thermal stability. The nanocellulose was further assembled into robust films with a tensile strength of 145 MPa and lightweight aerogels with a compressive strength of 27.6 kPa at 90% strain and a thermal conductivity of 0.251 W·m-1·K-1. This study elucidates the relationship among processing conditions, structural evolution and material properties during the production of carboxylated nanocellulose from hemp stalk, thereby providing a practical foundation for the sustainable valorization of agricultural residues into high value cellulose materials.

In this work, deep eutectic solvent (DES) based on imidazole and triethylmethylammonium chloride was used as a reaction medium for the esterification of cellulose nanofiber (CNF) and all-cellulose composite (ACC) films with n-octylsuccinic anhydride (OSA) to obtain high strength and sustainable films with increased hydrophobicity. Diffuse reflectance infrared Fourier transform spectroscopy and X-ray photoelectron spectroscopy were used to prove the success of the modification. The mechanical strength of the modified films was analyzed in dry, humid, and wet conditions, and the hydrophobicity of the films was indicated in terms of contact angle measurements. In addition, water absorption and transparency of the films were characterized. The modification was proven to be simple and fast, and mild conditions of 80 °C reaction temperature and 1 h reaction time were used. DES/OSA- modified CNF film exhibited better mechanical properties in dry, humid, and wet conditions compared to reference CNF film, and DES/OSA-modified ACC film displayed notable higher mechanical properties in wet state compared to that of reference CNF film (31 MPa tensile strength and 6.1% strain at break vs. 18 MPa and 2.2%, respectively). These improvements were partly attributed to higher contact angles of modified films (ACC-DES/OSA 60° and CNF-DES/OSA 51°) compared to CNF film (37°).

The hydrophilicity of nanocellulose materials mitigates their good mechanical and oxygen barrier properties when exposed to humid conditions. It also limits nanocellulose use in many applications where water is present. This study reveals hydrophobic modification of cellulose nanofiber (CNF) films with vinyl esters of variable alkyl chain length using deep eutectic solvent (DES) of imidazole and triethylmethylammonium chloride as a reaction medium. Additionally, the influence of ultraviolet-ozone (UV/O3) pretreatment on CNF film modification in DES was addressed. The esterification of CNF films in DES was proven to be a simple and fast approach to increase the hydrophobicity of the films (increasing the contact angle from 38° to 107°), requiring only a 15 min reaction time and reaction temperature of 80 °C. Moreover, the modification improved water vapor barrier properties of the films and resulted in improved mechanical properties at wet state, especially with films treated with UV and ozone before modification.

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In this study, nanocrystalline cellulose (NCC) was grafted with lauric acid, palmitic acid, and stearic acid and used as stabilizer to prepare styrene butyl acrylate emulsion. The properties of the emulsion were determined, and the mechanism of modified NCC (MNCC) stabilized emulsion was analyzed. Results showed that long-chain fatty acids were grafted to NCC through esterification initiated at a low temperature. When the dosage of L-MNCC, P-MNCC, and S-MNCC was 0.05%, the styrene-acrylic emulsion had 92.5%, 94.2%, and 96.3% conversion rates, respectively, and exhibited good dilution, pH, Ca2+, and centrifugal stability. The particle size of styrene-acrylic emulsion was approximately 460 nm, and the absolute value of the Zeta potential increased with the MNCC concentration. According to the images of optical microscopy and the transmission electron microscope, the MNCC was adsorbed onto the surface of styrene-acrylic emulsion droplets. The synergistic effect from the electrostatic repulsion of MNCC, the hydrophile lipophilicity of MNCC, and the spatial hindrance of the MNCC adsorption layer provided good stability for the styrene-acrylic emulsion. Therefore, MNCC could replace traditional surfactants in stabilizing emulsion.

To overcome the limited mechanical strength and poor stability of conventional gels in high-temperature, high-salinity oilfield environments, a novel nanocellulose-reinforced hydrogel (AM/AA/PCNF) was developed through a multistep chemical modification strategy. Nanocellulose served as a rigid backbone and was successively modified via epoxide ring-opening, methacryloyl esterification, and polydopamine functionalization, forming a three-dimensional network with multiple dynamic crosslinking interactions. The resulting composite hydrogel exhibited outstanding comprehensive properties when the PCNF content was 3 wt%: a tensile strength of 2.6 MPa, fracture energy of 8.95 MJ/m3, and compressive strength of 360 kPa—all markedly superior to those of conventional hydrogel systems. Under simulated downhole conditions (120 °C, 6 MPa, and 5 wt% salinity), the hydrogel demonstrated excellent plugging performance across sand beds of varying particle sizes (60–80 mesh to 20–40 mesh), maintaining cumulative fluid loss within 28.4–42.5 mL. Mechanistic investigations indicate that the enhanced performance stems from the synergistic combination of a rigid nanocellulose scaffold and multiple dynamic interactions, which facilitate a self-adaptive plugging mechanism. The study delivers both theoretical and practical foundations for designing advanced plugging systems.

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This review provides a comprehensive analysis of nanocellulose production, characterization, and applications, with a particular focus on its use in membranes and films for healthcare applications. The diverse sources of nanocellulose, including wood-based materials, agricultural byproducts, algae, and bacteria, are explored, highlighting their renewability, environmental benefits, and adaptability for specialized applications. The review also examines various pretreatment and processing methods, such as mechanical, chemical, and enzymatic treatments, outlining their roles in achieving desirable nanocellulose properties. Additionally, surface modification techniques, including amidation and esterification, are discussed for enhancing compatibility, stability, and performance when nanocellulose is integrated into composite materials. A novel mechanochemical approach is highlighted as a sustainable and energy-efficient fibrillation technique that reduces the environmental impact of nanocellulose production. Furthermore, the chemical modification and functionalization of nanocellulose are analyzed to expand its capabilities in advanced biomedical applications, including tissue engineering scaffolds that provide structural support for cell growth, wound dressings that leverage nanocellulose's antimicrobial and moisture-retentive properties, and drug delivery systems that utilize its biocompatibility and tunable release characteristics. The review concludes with future research directions, emphasizing the need for continued optimization of processing techniques, hybrid material development, and stimuli-responsive nanocellulose systems to unlock new biomedical and industrial applications.

In this study, biocomposite materials were developed by reinforcing a biobased unsaturated polyester resin with cellulose nanofibers to meet the demand for sustainable, high-performance materials. The inherent hydrophilicity and abundant surface functionalities of nanocellulose pose challenges for integration with hydrophobic polymer matrices, such as unsaturated polyester resins. To address this, a purification-free, one-step modification method was introduced in which dimethyl itaconate acts simultaneously as an esterification agent and solvent. The resulting reaction mixture was used directly as a reactive diluent, eliminating hazardous solvents and additional purification steps. Incorporation of modified nanocellulose resulted in notable performance enhancements, including a 23% increase in tensile strength at 0.3 wt % of modified nanocellulose compared to the neat resin and elevated glass transition temperatures across all samples. These findings emphasize the potential of the developed modification strategy to improve performance and sustainability, helping bridge the gap between sustainable polymer composites and their wider industrial application.

Jute fibers (JFs), in which two-thirds of their total mass is cellulose, are valuable bio-fibers employed from the household to technical applications in the environmental, pharmaceutical, and energy storage fields. However, their poor interfacial adhesion with polymer matrices hinders their widespread industrial application, particularly in composite materials. In this study, JFs were modified by grafting thiol moieties through mild oxidation, followed by esterification in an aqueous solution to enhance their functional performance and broaden their industrial utility. First of all, JFs were collected from a local market and pretreated with an alkali solution and oxidized with 20% Fenton reagent (FR). The desired grafting of thiol moieties was achieved by refluxing the initially oxidized JFs with ethane-1,2-dithiol in acetonitrile using trifluoroacetic acid as a catalyst at 60 °C for 4 h. These materials were characterized by Fourier-transform infrared spectroscopy, conductometric titration, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, fiber strength and contact angle analyses. The characteristic features of the –COOH groups and conductometric titration confirmed that the amount of –COOH groups decreased after thioesterification, as expected. The degree of oxidation of cellulose on the fiber surface was about 4.5%. The changes in crystallinity, surface morphology, tensile strength, and thermal stability support the efficient grafting of thiol moieties on the surface of JFs. The absorption bands corresponding to the –C <svg xmlns="http://www.w3.org/2000/svg" version="1.0" width="13.200000pt" height="16.000000pt" viewBox="0 0 13.200000 16.000000" preserveAspectRatio="xMidYMid meet"><metadata> Created by potrace 1.16, written by Peter Selinger 2001-2019 </metadata><g transform="translate(1.000000,15.000000) scale(0.017500,-0.017500)" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg> O and –C(O)–S– groups in the FT-IR spectra suggested the desired modification. 20% FR was sufficient for introducing a significant amount of these groups (280.39 μmol g−1). The increased hydrophobicity of the thiol-grafted JFs, as evaluated by contact angle measurements, evidenced the expected modification. With this enhanced surface functionality, the modified JFs show potential for applications in heavy metal remediation, industrial dye removal, wastewater treatment, and composite reinforcement, offering a sustainable and eco-friendly solution to environmental and industrial challenges.

ABSTRACT With the rapid development of the economy and changes in dietary structure, there is an excessive intake of high sugar and high-fat foods. To address this issue, in this study, we grafted palmitic acid onto CNC in the form of ester groups and evaluated its adsorption performance. Research had found that among these three methods, the CDI catalytic method can successfully obtain esterification modified CNC while also taking into account its environmentally friendly and pollution-free characteristics. Compared with CNC, its adsorption capacity for oil had increased, with the maximum adsorption capacity increasing from 35.80 g/g to 46.91 g/g. Meanwhile, the degree of esterification substitution of esterification modified CNC was measured, and the result was 0.03. Especially, after adding CNC-PA, the hydrolysis of fat was significantly reduced during the simulated digestion in vitro, whilst the absorption of fat in the intestine was significantly inhibited. In vivo testing also confirmed that consuming a diet containing CNC-PA significantly reduced elevated levels of triglycerides (TG) compared to the high-fat control group while long-term feeding of a diet containing CNC-PA reduced weight and fat accumulation.

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Esterification and click-chemistry were evaluated as surface modification treatments for TEMPO-oxidized nanocelluloses (TONC) using Polycaprolactone-diol (PCL) as modifying compound in order to improve the dispersion of nanofibers in organic media. These two grafting strategies were analyzed and compared. The first consists of grafting directly the PCL onto TONC, and was carried out by esterification between hydroxyl groups of PCL and carboxyl groups of TONC. The second strategy known as click-chemistry is based on the 1,3-dipolar cycloaddition reaction between azides and alkyne terminated moieties to form the triazole ring between PCL and TONC. The grafted samples were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Thermogravimetry analysis (TGA). Further, the effects of the two treatments on the surface hydrophobization of TONC were investigated by contact angle measurements. The results show that both methods confirm the success of such a modification and the click reaction was significantly more effective than esterification.

In order to lift the barrier of a poor interfacial interaction between cellulosic plant fibers and polymeric matrices in biocomposites, an eco-friendly surface modification of fibers was explored. A solvent-free gas-phase ester-ification applied to cellulose particles allowed to graft palmitoyl moieties on their surface in order to make them more compatible with non-polar polymers for composite applications. The efficiency of the treatment was evidenced from FT-IR analysis, and the degree of substitution (DS) was quantified by solid-state 13 C NMR spectroscopy. The effect of surface grafting on resulting intrinsic characteristics of cellulose particles, i.e. crys-tallinity, thermal stability, morphology, surface free energy and water vapor sorption were investigated respectively by X-ray diffraction, thermogravimetric analysis, SEM observations coupled with image analysis, contact angle measurements and dynamic vapor sorption system (DVS). It was shown that a DS as low as 0.01 was enough to drastically increase the hydrophobicity of cellulose particles without affecting the inner properties of cellulose.

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Abstract To deal with the heat dissipation problem produced by a high integrated circuit, the preparation of heat spreaders with excellent heat transportation performance is increasing in demand. The Ti3C2 MXene sheets and copper particles were fully contacted with cellulose nanofibers by a high-speed mixer, and the composite film was prepared as a heat spreader under the action of the vacuum-assisted filtration. The MXene sheets are connected by the esterification of the carboxyl group in MXene and the hydroxyl group in cellulose nanofibers to form a chemical bond and consist of the main skeleton of the composite film. Due to the synergistic effects of MXene and copper particles, the in-plane and out-of-plane thermal conductivities of the composite film reach 24.96 and 2.46 W m−1 K−1, respectively. Compared with the pure cellulose nanofiber films, the thermal conductivity of composite films increased by 2819.2 and 187.6%, respectively. By designing two applications of composite films in the actual use process, the excellent heating conduction abilities in two directions have been proved. This measure to improve the thermal conductivities of composite films by MXene-copper binary fillers also provides ideas for the novel heat spreader. Graphical abstract

Cellulose is the richest renewable polymer source on the earth. TEMPO-mediated oxidized cellulose nanofibers are deduced from enormously available wood biomass and functionalized with carboxyl groups. The preparation procedure of TOCNFs is more environmentally friendly compared to other cellulose, for example, MFC and CNCs. Due to the presence of functional carboxyl groups, TOCNF-based materials have been studied widely in different fields, including biomedicine, wastewater treatment, bioelectronics and others. In this review, the TEMPO oxidation mechanism, the properties and applications of TOCNFs are elaborated. Most importantly, the recent advanced applications and the beneficial role of TOCNFs in the various abovementioned fields are discussed. Furthermore, the performances and research progress on the fabrication of TOCNFs are summarized. It is expected that this timely review will help further research on the invention of novel material from TOCNFs and its applications in different advanced fields, including biomedicine, bioelectronics, wastewater treatment, and the energy sector.

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This work investigates multifunctional composite films synthesized with cellulose nanofibers (CNFs) and poly(vinyl alcohol) (PVA). First, TEMPO-oxidized CNFs were modified in the heterogeneous phase with benzophenone, diisocyanate, and epoxidized soybean oil via esterification reactions. A thorough characterization was carried out via elemental analysis as well as FT-IR and X-ray photoelectron spectroscopies and solid-state NMR. Following, the surface-modified CNFs were combined with PVA to endow composite films with UV-absorbing capabilities while increasing their thermomechanical strength and maintaining a high light transmittance. Compared to neat PVF films, the tensile strength, Young modulus, and elongation of the films underwent dramatic increases upon addition of the reinforcing phase (maximum values of ∼96 MPa, ∼ 714 MPa, and ∼350%, respectively). A high UV blocking performance, especially in the UVB region, was observed for the introduced multifunctional PVA films at CNF loadings below 5 wt %. The trade-off between modified nanofibril function as interfacial reinforcement and aggregation leads to an optimum loading. The results indicate promising applications, for example, in active packaging.

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Bioplastics based on lignin-containing cellulose nanofibrils (LCNF) have emerged as attractive alternatives to petrochemical plastics. However, the preparation of LCNF-based bioplastics with excellent wet-mechanical properties and water stability remains challenging. This study reports a sustainable route for the preparation of LCNF-based bioplastics with excellent wet mechanical properties and water stability. First, a deep eutectic solvent was employed to pretreat the bamboo powder to partially remove lignin. Then, the pretreated bamboo powder was esterified by one-step maleic anhydride (MAH) esterification to produce maleic anhydride-esterified LCNF (MLCNF). MLCNF exhibits a high aspect ratio (337), fine diameter (4.6 nm), and high surface charge (1.67 mmol/g). These properties endow MLCNF bioplastics with excellent wet elongation at break (41 %, significantly higher than other cellulose-based bioplastics), wet tensile strength (43.5 MPa), wet toughness (9.8 MJ m-3), dry tensile strength (164 MPa), dry toughness (15.7 MJ m-3), thermal stability, hydroplastic properties, and water stability (water contact angle: 91°). This research provides a straightforward, eco-friendly, and efficient approach for developing bioplastics with excellent wet mechanical properties and water stability using renewable lignocellulosic resources, with the potential to replace petrochemical plastics.

Cellulose nanofibril (CNF) is a natural biodegradable biopolymer with excellent mechanical and barrier properties. However, it is susceptible to moisture-induced deterioration of its properties. Attachment of phenolic acids can improve its hydrophobicity and provide additional active functionalities such as antioxidant properties. In this study, CNF films were esterified to vanillic and syringic acid through two different reaction mechanisms. The films were investigated for evidence of modification, hydrophobicity, mechanical properties, crystallinity, thermal stability, and antioxidant properties. Results indicate that esterification with vanillic and syringic acids imparted antioxidant activity to CNF films, with a significantly higher ABTS+· scavenging activity (76 ± 18%) when compared to control CNF films (30 ± 6%). Similarly, esterification of phenolic acids significantly improved the hydrophobicity of the films with a water contact angle of 94 ± 3° when compared to control CNF films (46 ± 5°). Covalent attachment of phenolic acids can improve hydrophobicity while providing additional functionality to CNF important for food packaging applications.

The Ibuprofen-Cellulose nanofibril (IBU-CNF) drug delivery system was prepared by esterification of Ibuprofen (IBU) and cellulose nanofibril (CNF) with isopropyl acetate as the solvent and sulfuric acid as the catalyst. The results showed that IBU was successfully grafted on to the CNF molecular chain and the crystal structure of CNF did not change. Moreover, the natural three-dimensional network structure was maintained to a large extent. The maximum drug loading of IBU-CNF was 151.38 mg/g. In vitro drug release showed that IBU-CNF was pH-responsive and could be released continuously over 24 h. The cumulative release rate was approximately 90% under alkaline conditions but was low under acidic conditions. UV-visible spectra revealed that IBU retained its chemical activity after in vitro release.

As environmental issues are hotly debated worldwide, finding suitable materials to replace petroleum-based materials as the next-generation packaging materials has become a research hotspot. Nanocellulose, as a biomass material widely available in nature, is favored for application in green packaging materials due to its environmentally friendly and bio-friendly characteristics. However, the unstable mechanical properties and strong hydrophilicity of nanocellulose limit its practical application in packaging materials. This paper starts with a discussion of nanocellulose-based packaging materials and focuses on methods to improve their mechanical and hydrophobic properties. The discussion on mechanical properties focuses on the contribution of carbon nanomaterials, which is then combined with hydrophobic modifications (including plant polyphenol modification, esterification, acetylation, in situ polymerization, etc.) to illustrate the impact on the performance of packaging materials in use. The relationship between the hydrophobic characteristics of packaging materials derived from nanocellulose and their comprehensive mechanical properties is meticulously elucidated. Furthermore, a theoretical framework is proposed, positing that enhancing the hydrophobicity of these materials can indirectly augment their mechanical attributes. This insight offers pivotal guidance for the advancement of next-generation, high-performance packaging materials based on nanocellulose.

: As non-degradable traditional plastics contribute to environmental pollution, biodegradable polymers have been identified as a promising alternative. However, inherent drawbacks such as low toughness, poor tensile strength, and reduced thermal degradation temperatures limit the further development of biodegradable polymers. Nanocellulose has the potential to enhance the properties of biodegradable polymers without compromising their biodegradability. However, the abundant hydroxyl groups in nanocellulose’s molecular chains result in poor compatibility with hydrophobic polymers, requiring surface modification prior to their combination. This review first introduces several common biodegradable polymers and three types of nanocellulose, followed by a comprehensive analysis of the recent advancements in the chemical modification methods of nanocellulose over the last five years. These methods encompass esterification, oxidation, silylation, and graft modification. The focus of this discussion is primarily on the modification strategies, enhancement effects, and mechanisms. Furthermore, the degradability and applications of modified nanocellulose composites are summarized. Finally, the main challenges hindering the development of chemically modified nanocellulose-reinforced biodegradable polymers are proposed. It is hoped that this review will inspire future researchers to develop industrially valuable chemically modified nanocellulose-reinforced biodegradable polymers.

As a kind of renewable nanomaterial, nanocellulose displays excellent performances and exhibits wide application potentials. In general, nanocellulose has strong hydrophilicity due to the presence of abundant hydroxyl groups or the hydrophilic functional groups introduced during the preparation process. Although these hydrophilic groups benefit the nanocellulose with great application potential that is used in aqueous media (e.g., rheology modifier, hydrogels), they do hinder the performance of nanocellulose used as reinforcing agents for hydrophobic polymers and reduce the stability of the self-assembled nanostructure (e.g., nanopaper, aerogel) in a high-humidity environment. Thus, this review aims to summarize recent advances in the hydrophobic modification of nanocellulose, mainly in three aspects: physical adsorption, surface chemical modification (e.g., silylation, alkanoylation, esterification), and polymer graft copolymerization. In addition, the current limitations and future prospects of hydrophobic modification of nanocellulose are proposed.

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Polysaccharides represent an ideal delivery platform for agrochemicals due to their biodegradability, biocompatibility, and abundance. However, hydrophilicity renders native polysaccharides ineffective at controlling the release of water-soluble agrochemicals. To overcome this limitation, we used a solvent-free, vapor-phase modification strategy to generate hydrophobic shells on the surface of nanofibrillated cellulose (CNF) prills and evaluated the effects of these tunable diffusion barriers on fertilizer release behavior. Hydrophobic shells of different thicknesses were created on CNF prills by esterification with acyl chlorides of varying alkyl chain lengths, although esterification did not hinder the inherent biodegradability of the CNFs. Fertilizer release rates were largely invariable to pH and NPK loading but were tunable over 3 orders of magnitude by varying the alkyl chain length and the degree of substitution (i.e., shell thickness). However, NPK release rates did not increase monotonically with increasing shell thickness; for long-chain (6 carbons or longer) esters, increases in shell thickness beyond optimal values increased release rates; SEM revealed that this originated from the introduction of fractures to the prills which act as diffusion channels. This work demonstrates the potential of controlled surface modification to generate a mineralizable and tunable NPK release platform from naturally sourced and sustainable feedstocks.

: Aerogels, renowned as ultra-lightweight solids with exceptional porosity and specific surface area, have emerged as pivotal materials for thermal insulation, catalysis, energy storage, and biomedicine. This review comprehensively evaluates the recent strides in sustainable, high-performance cellulose-based aerogels, emphasizing their fabrication, functionalization, and application prospects. It details the extraction of cellulose from diverse sources and its subsequent processing into nanocellulose (e.g., cellulose nanofibrils and nanocrystals), which serves as the fundamental building block for aerogel synthesis. The critical sol-gel transition, solvent selection, and the pivotal role of drying techniques—freeze-drying, supercritical drying, and ambient pressure drying—in determining final aerogel architecture and properties are systematically analyzed. Special emphasis is placed on the advanced chemical modification of nanocellulose, including esterification, click chemistry, etherification, silanization, and amidation, which tailors surface chemistry to impart hydrophobicity, reactivity, or specific binding sites. The profound influence of cellulose source characteristics (aspect ratio, crystallinity, surface charge) on the pore-forming mechanism and aerogel performance is thoroughly discussed, bridging raw material selection with microstructure design. The review further elucidates the engineering of hybrid and composite aerogels by integrating silica, graphene, polymers, semiconductors, and metal-organic frameworks (MOFs), which synergistically enhance functionalities for targeted applications such as adsorption, photocatalysis, energy storage, sensing, and biomedical engineering. Despite significant progress, challenges remain in scalable green fabrication, balancing ultra-high porosity with mechanical robustness, and deepening the mechanistic understanding in complex applications. This work consolidates the current state-of-the-art, identifies key knowledge gaps, and provides a forward-looking perspective on the development of cellulose aerogels as versatile platforms for next-generation sustainable technologies.

The incorporation of nanocellulose (CNF) as a filler into resin matrix to enhance its mechanical properties has been studied by scientists for a long time, and the homogeneous dispersion of CNF is the focus of the research in this process. In this study, CNF was graft-modified using methyl methacrylate (MMA) and then dispersed into a light-curing resin with methyl methacrylate (PMMA) as the base at different concentrations for DLP-type 3D printing. The successful preparation of PMMA-g-CNF was demonstrated using FTIR spectroscopy. At the same time, its water contact angle and dispersion were characterized to prove the success of hydrophobic modification, which slightly reduced the crystallinity of the modified samples without changing the crystal shape. The tensile strength of the 3D printed samples added with PMMA-g-CNF improved after sufficient esterification by the post-curing process. When the addition amount was 0.75%, the tensile strength was improved by 114.8%. The microscopic morphology of the 3D printed products was also observed by scanning electron microscopy, which showed that PMMA-g-CNF was more uniformly dispersed in the resin matrix than CNF, and its use as a filler disperse stress contributed to the mechanical strength.

Nanocellulose (NC) isolated from natural cellulose resources, which mainly includes cellulose nanofibril (CNF) and cellulose nanocrystal (CNC), has garnered increased attention in recent decades due to its outstanding physical and chemical properties. Various chemical modifications have been developed with the aim of surface-modifying NC for highly sophisticated applications. This review comprehensively summarizes the chemical modifications applied to NC so far in order to introduce new functionalities to the material, such as silanization, esterification, oxidation, etherification, grafting, coating, and others. The new functionalities obtained through such surface-modification methods include hydrophobicity, conductivity, antibacterial properties, and absorbability. In addition, the incorporation of NC in some functional materials, such as films, wearable sensors, cellulose nanospheres, aerogel, hydrogels, and nanocomposites, is discussed in relation to the tailoring of the functionality of NC. It should be pointed out that some issues need to be addressed during the preparation of NC and NC-based materials, such as the low reactivity of these raw materials, the difficulties involved in their scale-up, and their high energy and water consumption. Over the past decades, some methods have been developed, such as the use of pretreatment methods, the adaptation of low-cost starting raw materials, and the use of environmentally friendly chemicals, which support the practical application of NC and NC-based materials. Overall, it is believed that as a green, sustainable, and renewable nanomaterial, NC is will be suitable for large-scale applications in the future.

With increasing environmental and ecological concerns due to the use of petroleum-based chemicals and products, the synthesis of fine chemicals and functional materials from natural resources is of great public value. Nanocellulose may prove to be one of the most promising green materials of modern times due to its intrinsic properties, renewability, and abundance. In this review, we present nanocellulose-based materials from sourcing, synthesis, and surface modification of nanocellulose, to materials formation and applications. Nanocellulose can be sourced from biomass, plants, or bacteria, relying on fairly simple, scalable, and efficient isolation techniques. Mechanical, chemical, and enzymatic treatments, or a combination of these, can be used to extract nanocellulose from natural sources. The properties of nanocellulose are dependent on the source, the isolation technique, and potential subsequent surface transformations. Nanocellulose surface modification techniques are typically used to introduce either charged or hydrophobic moieties, and include amidation, esterification, etherification, silylation, polymerization, urethanization, sulfonation, and phosphorylation. Nanocellulose has excellent strength, high Young's modulus, biocompatibility, and tunable self-assembly, thixotropic, and photonic properties, which are essential for the applications of this material. Nanocellulose participates in the fabrication of a large range of nanomaterials and nanocomposites, including those based on polymers, metals, metal oxides, and carbon. In particular, nanocellulose complements organic-based materials, where it imparts its mechanical properties to the composite. Nanocellulose is a promising material whenever material strength, flexibility, and/or specific nanostructuration are required. Applications include functional paper, optoelectronics, and antibacterial coatings, packaging, mechanically reinforced polymer composites, tissue scaffolds, drug delivery, biosensors, energy storage, catalysis, environmental remediation, and electrochemically controlled separation. Phosphorylated nanocellulose is a particularly interesting material, spanning a surprising set of applications in various dimensions including bone scaffolds, adsorbents, and flame retardants and as a support for the heterogenization of homogeneous catalysts.

The development of science and technology brings forward higher and higher requirements for the properties of materials. Nanocellulose, with many fascinating properties including large specific surface area, template structure, good modifiability, biodegradability, and etc., has wide application prospects. The surface properties and interfacial compatibility of nanocellulose are the keys to its application performance. This review mainly summarizes the colloid and surface chemistry of nanocellulose and their effects on the dispersity in various solvents and polymer matrices, and especially focuses on the impact of surface hydrophilicity/hydrophobicity, charge repulsion and steric hindrance on the dispersion properties. Various surface modification methods to improve the dispersion performance of nanocellulose, such as oxidation, etherification, esterification, amidation, graft polymerization, and etc., are summarized. In addition, the application of nanocellulose as the dispersant for Pickering emulsion, carbon nanomaterials, metal nanoparticles and etc. is also introduced. The development trend and potential application of nanocellulose are finally prospected.

Abstract Presently, a plenty of concerns related to the environment are due to the overuse of petroleum-based chemicals and products; the synthesis of functional materials, starting from the natural sources, is the current trend in research. The interest for nanocellulose has recently increased in a huge range of fields, from the material science to the biomedical engineering. Nanocellulose gained this leading role because of several reasons: its natural abundance on this planet, the excellent mechanical and optical features, the good biocompatibility and the attractive capability of undergoing surface chemical modifications. Nanocellulose surface tuning techniques are adopted by the high reactivity of the hydroxyl groups available; the chemical modifications are mainly performed to introduce either charged or hydrophobic moieties that include amination, esterification, oxidation, silylation, carboxymethylation, epoxidation, sulfonation, thiol- and azido-functional capability. Despite the several already published papers regarding nanocellulose, the aim of this review involves discussing the surface chemical functional capability of nanocellulose and the subsequent applications in the main areas of nanocellulose research, such as drug delivery, biosensing/bioimaging, tissue regeneration and bioprinting, according to these modifications. The final goal of this review is to provide a novel and unusual overview on this topic that is continuously under expansion for its intrinsic sophisticated properties.

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Background and Aims: Cholesterol ester (CE) biosynthesis and homeostasis play critical roles in many cancers, including HCC, but their exact mechanistic contributions to HCC disease development require further study. Approach and Results: Here, we report on a proposed role of tumor suppressor P53 in its repressing ubiquitin‐specific peptidase 19 (USP19) and sterol O‐acyltransferase (SOAT) 1, which maintains CE homeostasis. USP19 enhances cholesterol esterification and contributes to hepatocarcinogenesis (HCG) by deubiquitinating and stabilizing SOAT1. Loss of either SOAT1 or USP19 dramatically attenuates cholesterol esterification and HCG in P53‐deficient mice fed with either a normal chow diet or a high‐cholesterol, high‐fat diet (HCHFD). SOAT1 inhibitor avasimibe has more inhibitory effect on HCC progression in HCHFD‐maintained P53‐deficient mice when compared to the inhibitors of de novo cholesterol synthesis. Consistent with our findings in the mouse model, the P53‐USP19‐SOAT1 signaling axis is also dysregulated in human HCCs. Conclusions: Collectively, our findings demonstrate that SOAT1 participates in HCG by increasing cholesterol esterification, thus indicating that SOAT1 is a potential biomarker and therapeutic target in P53‐deficient HCC.

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