Cellulose Nanofibrils Research Articles

In Vitro Characterizations of Poly(Ethylene Glycol) Dimethacrylate)-Nanofibrillated Cellulose as an Injectable Biomaterial Substitute for Herniated Nucleus Pulposus

Highlights: Novel synthetic biopolymer hydrogels were successfully prepared using photopolymerization method based on pristine PEGDMA and pristine NFC. Biocomposite hydrogel based on pristine PEGDMA: pristine NFC can be developed as a substitute biomaterial for the nucleus pulposus in cases of herniated nucleus pulposus which can afford for clinical application standards Abstract As many as 30-80% of cases low back pain (LBP) is frequently attributed to herniated nucleus pulposus (HNP) with 18-29% of instances reported in Indonesia. HNP can cause in motor weakness, sensory disturbances and decreased physiological reflexes. HNP occurs due to protrusion of the intervertebral disc through the annulus fibrosus which can be caused by the rupture of the annulus fibrosus or decreased proteoglycans (PGs). Hydrogel implant material is injected into the disc space, which can restore disc thickness caused by disc degeneration with minimal invasive. This study utilizes poly(ethylene glycol) dimethacrylate (PEGDMA):nanofibrillated cellulose (NFC) used to treat first-degree HNP using photopolymerization method. PEGDMA is very hydrophilic and is able to produce hydrogel. The addition of NFC to the PEGDMA precursor that forms a hydrogel was able to show mechanical properties as a hydrogel biocomposite candidate. This research to characterize of PEGDMA:NFC for biomaterial substitute of HNP. Characterizations involves Fourier Transform Infrared (FTIR) test, viscosity assessment and in vitro injection model test. PEGDMA:NFC concentrations explored include 1:0 (control), 1:0.5 (K1 sample), 1:0.75 (K2 sample) and 1:1 (K3 sample). FTIR test can indicating each functional group for hydrogel biomaterial of PEGDMA:NFC. Based on characterization results, the K3 sample has the best results with a concentration of 1:1. The viscosity value was 74,67 dPa.s and in vitro injection model test showed the addition of NFC indicates the hydrogel state when released from the mold will be not ruptured. Hydrogels can be injected with syringe 18 gauge. Consequently, the study concludes that the PEGDMA:NFC biocomposite hydrogel can be effectively applied in cases of herniated nucleus pulposus.

3D-Printed Collagen-Nanocellulose Hybrid Bioscaffolds with Tailored Properties for Tissue Engineering Applications.

Hybrid collagen (Coll) bioscaffolds have emerged as a promising solution for tissue engineering (TE) and regenerative medicine. These innovative bioscaffolds combine the beneficial properties of Coll, an important structural protein of the extracellular matrix, with various other biomaterials to create platforms for long-term cell growth and tissue formation. The integration or cross-linking of Coll with other biomaterials increases mechanical strength and stability and introduces tailored biochemical and physical factors that mimic the natural tissue microenvironment. This work reports on the fabrication of chemically cross-linked hybrid bioscaffolds with enhanced properties from the combination of Coll, nanofibrillated cellulose (NFC), carboxymethylcellulose (CMC), and citric acid (CA). The bioscaffolds were prepared by 3D printing ink containing Coll-NFC-CMC-CA followed by freeze-drying, dehydrothermal treatment, and neutralization. Cross-linking through the formation of ester bonds between the polymers and CA in the bioscaffolds was achieved by exposing the bioscaffolds to elevated temperatures in the dry state. The morphology, pores/porosity, chemical composition, structure, thermal behavior, swelling, degradation, and mechanical properties of the bioscaffolds in the dry and wet states were investigated as a function of Coll concentration. The bioscaffolds showed no cytotoxicity to MG-63 human bone osteosarcoma cells as tested by different assays measuring different end points. Overall, the presented hybrid Coll bioscaffolds offer a unique combination of biocompatibility, stability, and structural support, making them valuable tools for TE.

Injectable, rapid self-healing, antioxidant and antibacterial nanocellulose-tannin hydrogels formed via metal-ligand coordination for drug delivery and wound dressing

Nanocellulose-based hydrogels have attracted increasingly attention due to their biocompatibility, biodegradability, and hydrophilic properties. In this work, we proposed a simple route to fabricate composite hydrogels using TEMPO oxidized cellulose nanofibrils (TOCNF) and tannin through metal-ligand coordination. Calcium ions were utilized to rapidly cross-link the carboxyl groups on TOCNF and the tannins' catechol moieties via metal-ligand bonding, resulting in the formation of TOCNF-Ca2+-T composite hydrogels. The incorporation of tannins endowed the hydrogel with high antioxidant and antibacterial properties. The rheological analysis revealed that the addition of tannin led to an improved gel strength of the composite hydrogel. The hydrogel was injectable and could autonomously self-healed in 1 min without any trigger. Tetracycline hydrochloride (TH) was successfully loaded into the composite hydrogels, achieving a maximum encapsulation rate of 97.32%. TOCNF-Ca2+-40%T demonstrated a cumulative drug release of 36% at pH 1.3 and 86% at pH 7.4, indicating its pH-responsive nature. These hydrogels, derived from plant sources, exhibited high antibacterial and antioxidant properties, as well as biocompatibility, rapid self-healing, and injectability, which open up new possibilities for applications in wound dressing and drug delivery.

Preparation of Cellulose Nanofibrils with the Pretreatments using Inexpensive Protic Ionic Liquids based on Dimeric Oxalic Acid Anions

AbstractPreparation of cellulose nanofibrils (CNFs) with the pretreatments using alkanolamine‐based protic ionic liquids (PILs) with dimeric oxalic acid anions ([(HOA)(H2OA)]−) was fully investigated. The cation type [ethanolamine ([MEA]+), diethanolamine ([DEA]+), triethanolamine ([TEA]+)], and water addition greatly influenced the CNF yields. Under the pretreatment conditions of 110 °C and 3 h, the CNF yields with different PIL‐based systems followed the order: [MEA][(HOA)(H2OA)]>[DEA][(HOA)(H2OA)]>[TEA][(HOA)(H2OA)], similar to their swelling capacities. The highest CNF yield of 85.0 % was obtained after the pretreatment with [MEA][(HOA)(H2OA)]‐water containing 30 wt % PILs. The optimal pH range of PILs‐water was 1.10–1.15. The good recyclability indicated that these inexpensive PILs can be employed as a simple and efficient pretreatment system for preparing CNFs. The physicochemical properties of the prepared CNFs were greatly changed by varying the PILs’ pretreatment systems. The thermal stability of CNFs was intimately connected with the crystalline structures and hydrogen bonding modes.

Effects of advanced nanomaterials on the respiratory system of a murine COPD model

This study assessed the effects of cellulose nanofibrils (CNFs) and multi-walled carbon nanotubes (MWCNTs) on lung inflammation in a cigarette smoke-induced chronic obstructive pulmonary disease (COPD) mouse model. Prior to instillation, COPD model mice displayed distinctive cellular compositions and elevated cytokine levels in bronchoalveolar lavage fluid (BALF). After intratracheal instillation of 80 μg CNFs, no significant histopathological changes, BALF composition alterations, or cytokine level shifts were observed on day 28. This suggests minimal lung impact and no interference with reducing smoke-induced inflammation. In contrast, the instillation of 80 μg MWCNTs resulted in significant histopathological changes, increased cellular composition, and elevated cytokine levels in BALF on day 28. These findings indicate that CNF exposure had little effect on the lungs and did not impede the reduction of smoke-induced inflammation, while MWCNT exposure hindered the attenuation of pulmonary inflammatory response. The study emphasizes the importance of considering diverse cases, including individuals with pre-existing respiratory conditions, when assessing occupational safety and health risks associated with advanced nanomaterial exposure.

A Versatile Shaping Method of Very-High Loading Porous Solids Paper Adsorbent Composites.

Owing to their high porosity and tunability, porous solids such as metal-organic frameworks (MOFs), zeolites, or activated carbons (ACs) are of great interest in the fields of air purification, gas separation, and catalysis, among others. Nonetheless, these materials are usually synthetized as powders and need to be shaped in a more practical way that does not modify their intrinsic property (i.e., porosity). Elaborating porous, freestanding and flexible sheets is a relevant shaping strategy. However, when high loadings (>70wt.%) are achieved the mechanical properties are challenged. A new straightforward and green method involving the combination softwood bleached kraft pulp fibers (S) and nano-fibrillated cellulose (NFC) is reported, where S provides flexibility while NFC acts as a micro-structuring and mechanical reinforcement agent to form high loadings porous solids paper sheets (>70wt.%). The composite has unobstructed porosity and good mechanical strength. The sheets prepared with various fillers (MOFs, ACs, and zeolites) can be rolled, handled, and adapted to different uses, such as air purification. As an example of potential application, a MOF paper composite has been considered for the capture of polar volatile organic compounds exhibiting better performance than beads and granules.

Shape and Stiffness Switchable Hydroplastic Wood with Programmability and Reproducibility.

Stiffness switchable materials (e.g., supramolecular polymers, metals) that alter their shape and mechanical properties in response to specific stimuli are potentially utilized in the structural engineering field but still limited due to the use of petroleum-based synthetic monomers and large energy consumption. Herein, a sustainable and facile solvent casting strategy is proposed to fabricate the "hydroplastic wood" with shape and stiffness switchable properties via cell wall wetting, cell wall softening and subsequent moisture evaporation. Therein, a wetting agent with low surface tension and low viscosity is utilized for covering the rough surface of solid wood to form a liquid lubricating layer, thereby increasing the interfacial wettability and achieving uniform softening of the cell walls. This interface wetting treatment can easily break through the hydro-plasticization process for thick wood (Balsa wood, Ochroma lagopus Swartz, density: 0.25 g/cm3; Pinewood, Pinus armandii, density: 0.38 g/cm3). Additionally, the capillary force arising from moisture evaporation induces the self-densification of oriented cellulose nanofibrils and achieves moisture-mediated shape design capabilities through periodic saturation-dehydration. This work makes hydroplastic wood a promising candidate for engineering materials because of its combined advantages of strong durability, formability, and load-carrying capacity.

Integration of wood-based components – Cellulose nanofibrils and tannic acid - into a poly(vinyl alcohol) matrix to improve functional properties

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 (Tg, Tonset) of the PVA biocomposite films were greatly improved, with a significant effect observed for the three-component PVA films. The Tg 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 Tonset 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.

High performance and flexible piezoelectric composite incorporating zinc oxide grown on the oxidized nanocellulose by two-step hydrothermal process

While the existed researches about cellulose based piezoelectric composite focused on the direct growth of ZnO on surface of cellulose based paper or membrane, this paper reports a ZnO based piezoelectric composite fabricated by growing ZnO in the cellulose nanofibril (CNF) dispersion substrate via two-step hydrothermal synthesis. After CNF was controllably oxidized to endow with appropriate carboxyl groups and size, it was used as a template and dispersant for in-situ polymerization of ZnO to be CNF@ZnO. Zn2+ is preferentially fixed on the scattered CNF for its active hydroxyl and carboxyl groups which serve as a uniform nucleation for the self-assembly of ZnO, so that it has a preferential orientation with optimal phase structure, one-dimensional rod-like structure, excellent dispersity, low interface energy and interfacial compatibility. Thus the assembled 4CNF/4CNF@ZnO composite membrane has a large elevation in the dielectric properties and piezoelectric performance. Moreover, the 4CNF/CNF@ZnO piezoelectric composite vacuum-impregnated with PDMS exhibits better piezoelectric performance with the open-circuit voltage as high as 25.6 V and the short-circuit current of 1100 nA. It can supply to light LED and has high sensitivity to body movement, indicating its great potential in pressure sensors and generators.

Facile fabrication of PF-540-Eu@TOCNF films with hydrophobic and photoluminescent properties

Based on the biodegradable natural polymer compound TEMPO-oxidized cellulose nanofibrils, and using EuCl3·6H2O, 3-aminopropyltrimethoxysilane and 1H,1H,2H,2H-perfluorooctyltrimethoxysilane as functional reagents, a novel type of cellulose nanofibril composite films with hydrophobic and photoluminescent properties was fabricated by a simple solvothermal method. The effects of reaction time, reaction temperature, Vol.% C2H5OH, solvents dosage, and n (Eu3+: COOH) on the photoluminescence and hydrophobicity of the films were investigated, while the films were characterized by using UV meter, fluorescence spectrometer, contact angle meter, FT-IR, XPS, SEM, EDS, TEM, XRD and TG. The results demonstrate that the surface of the film is uniformly loaded with Eu3+ and emits bright red light under UV irradiation, which has excellent photoluminescence, hydrophobicity (water contact angle 137.6°) and higher thermal stability. And high-value applications of nanocellulose in the fields of bioimaging, anti-counterfeiting and sensing detection in the low-temperature and high-humidity environment will be expanded.

Immobilization of enzymes on functionalized cellulose nanofibrils for bioremediation of antibiotics: Degradation mechanism, kinetics, and thermodynamic study

The deteriorating environmental conditions due to increasing emerging recalcitrant pollutants raised a severe concern for its remediation. In this study, we have reported antibiotic degradation using free and immobilized HRP. The functionalized cellulose support was utilized for efficient immobilization of HRP. Approximately 13.32 ± 0.52 mg/g enzyme loading was achieved with >99% immobilization efficiency. The higher percentage of immobilization is attributed to the higher surface area and carboxylic groups on the support. The kinetic parameter of immobilized enzymes was Km = 2.99 mM/L for CNF-CA@HRP, which is 3.5-fold more than the Michaelis constant (Km = 0.84794 mM/L) for free HRP. The Vmax of CNF-CA@HRP bioconjugate was 2.36072 mM/min and 0.558254 mM/min for free HRP. The highest degradation of 50, 54.3, and 97% were achieved with enzymatic, sonolysis, and sono-enzymatic with CNF-CA@HRP bioconjugate, respectively. The reaction kinetics analysis revealed that applying ultrasound with an enzymatic process could enhance the reaction rate by 2.7–8.4 times compared to the conventional enzymatic process. Also, ultrasound changes the reaction from diffusion mode to the kinetic regime with a more oriented and fruitful collision between the molecules. The thermodynamic analysis suggested that the system was endothermic and spontaneous. While LC-MS analysis and OTC's degradation mechanism suggest, it mainly involves hydroxylation, secondary alcohol oxidation, dehydration, and decarbonylation. Additionally, the toxicity test confirmed that the sono-enzymatic process helps toward achieving complete mineralization. Further, the reusability of bioconjugate shows that immobilized enzymes are more efficient than the free enzyme.

Green preparation of antibacterial shape memory foam based on bamboo cellulose nanofibril and waterborne polyurethane for adaptive relief of plantar pressure

This study developed an aqueous solution blending and freeze-drying method to prepare an antibacterial shape memory foam (WPPU/CNF) based on waterborne PHMG-polyurethane and cellulose nanofibers derived from bamboo in response to the increasing demand for environmentally friendly, energy conserving, and multifunctional foams. The obtained WPPU/CNF composite foam has a highly porous network structure with well-dispersed CNFs forming hydrogen bonds with the WPPU matrix, which results in a stable and rigid cell skeleton with enhanced mechanical properties (80 KPa) and anti-abrasion ability. The presence of guanidine in the polyurethane chain endowed the WPPU/CNF composite foam with an instinctive and sustained antibacterial ability against Escherichia coli and Staphylococcus aureus. The WPPU/CNF composite foam exhibited a water-sensitive shape memory function in a cyclic shape memory program because of the chemomechanical adaptability of the hydrogen-bonded network of CNFs in the elastomer matrix. The shape-fixation ratio for local compression reached 95 %, and the shape-recovery rate reached 100 %. This allows the WPPU/CNF pad prototype to reversibly adjust the undulation height to adapt to plantar ulcers, which can reduce the local plantar pressure by 60 %. This study provides an environmentally friendly strategy for cellulose-based composite fabrication and enriches the design and application of intelligent foam devices.

Cellulose/nanocarbon composite based multifunctional aerogels for thermal management

Renewable resource-based aerogels have attracted numerous attention due to the requirement on sustainable multifunctional materials for thermal management. A series of cellulose and nanocarbon composite aerogels have been prepared from a blend of carboxylated cellulose nanofibril (CCNF) with carbon nanotube (CNT), graphene oxide (GO), or carbon fiber (CF) using directional freezing method. CCNF/nanocarbon aerogels from bidirectional freezing exhibit higher compression strength due to bridge structures that are induced by temperature gradient horizontally and vertically. Meanwhile, CCNF/carbon aerogels from bidirectional freezing also have thermal conductivity coefficient (λ) as low as 0.0308 W/(m·K), which increases to 0.0388 W/(m·K) after calcination. The dispersed linear carbon materials CF and CNT in CCNF matrix lead to thermoelectric, Joule heating and photothermal performance of CCNF/nanocarbon aerogels, which is also promoted by calcination. The Seebeck coefficient of CCNF/nanocarbon aerogels ranges from 0.027 to 0.067 mV/K and change into 0.037–0.044 mV/K due to the more uniform carbon network formed after high temperature treatment. A 5–15 V input voltage can induce a temperature increase of 62 ∼ 303 °C for composite aerogel after calcination. A laser with 0.3 W power can result in a rapid temperature increase even to 200 °C in seconds for composite aerogel with and without calcination. These kinds of CCNF/nanocarbon based composite aerogels exhibit ability in thermal management, including thermal insulation, thermoelectric, electric and photo induced heating, which are good candidates for multifunctional aerogels.

Radiation-induced admicellar polymerization of methacrylate acid for pH responsive cellulose nanofibrils

Radiation-induced admicellar polymerization of methacrylate acid for pH responsive cellulose nanofibrils

Cellulose nanofibril/titanate nanofiber modified with CdS quantum dots hydrogel with 3D porous structure: A stable photocatalytic adsorbent for Cr(VI) removal

A novel cellulose nanofibril/titanate nanofiber modified with CdS quantum dots hydrogel (CTH) was synthesized as an effective, stable, and recyclable photocatalytic adsorbent using cellulose nanofibril (CN), titanate nanofiber (TN), and CdS quantum dots. Within the CTH structure, CN formed an essential framework, creating a three-dimensional (3D) porous structure that enhanced the specific surface area and provided abundant adsorption sites for Cr(VI). Simultaneously, TN modified with CdS quantum dots (TN-CdS) served as a nanoscale Z-type photocatalyst, facilitating the efficient separation of photoinduced electrons and holes, further increasing the photocatalytic efficiency. The morphological, chemical, and optical properties of CTH were thoroughly characterized. The CTH demonstrated the maximum theoretical adsorption capacity of 373.3 ± 14.2 mg/g, which was 3.4 times higher than that of CN hydrogel. Furthermore, the photocatalytic reduction rate constant of the CTH was 0.0586 ± 0.0038 min−1, which was 6.4 times higher than that of TN-CdS. Notably, CTH displayed outstanding stability, maintaining 84.9 % of its initial removal efficiency even after undergoing five consecutive adsorption–desorption cycles. The remarkable performance of CTH in Cr(VI) removal was attributed to its 3D porous structure, comprising CN and TN-CdS. These findings provide novel insights into developing a stable photocatalytic adsorbent for Cr(VI) removal.

Aerogel composite based on cellulose nanofibril and poly vinyl alcohol as insulation for meat packaging

In this study cellulose nanofibrils (CNFs) were produced by a chemo-mechanical technique from peanut shells and CNF/poly (vinyl alcohol) (PVA) aerogels were developed using a freeze-drying process. The morphological characteristics of the CNFs and aerogels were studied by scanning electron microscopy. Optimum aerogels were selected based on average pore size, physical properties, thermal conductivity, and mechanical features. The chemical properties of cellulose, CNF, PVA, and CNF/PVA aerogel were characterized using Fourier Transform Infrared spectroscopy. X-ray diffraction pattern of the aerogel displayed a minor decrease in the crystallinity index after cross-linking of CNF with PVA. Cross-linking CNF with PVA increased the thermal stability of aerogel. Aerogels were used as insulator for meat packaging to control temperature fluctuation during the cold chain. The produced package using aerogels could keep meat temperature during temperature fluctuation two times better than conventional one. The use of aerogels for the meat packaging resulted in a better preservation of physicochemical (pH, color properties, hardness and total volatile basic nitrogen) and microbial properties. The results indicated that CNF/PVA aerogel with ultra-low density (16.39 kg/m3), highly porous (98.43%), low thermal conductivity (0.033 W/m.K), and high compressive recoverability (84.66% at 50% strain and 65.71 % at 80% strain) can increase shelf life of meat during temperature fluctuations in cold storage and transportation.

Characterization of spray dried cellulose nanofibrils produced by a disk refining process at different fineness levels

Three types of wood pulp feedstocks including bleached softwood kraft, unbleached softwood kraft and old corrugated containers were disk refined to produce cellulose nanofibrils at different fineness levels ranging from 50 to 100%, and the resulting aqueous suspensions of cellulose nanofibrils were spray dried. The spray drying experiments were carried out to examine different processing conditions for the different CNF feedstock types and fines level at various suspension concentrations to produce dry samples with free-flowing powder morphologies. The fineness levels and solids contents of CNF suspensions were set to 80% or more and 1.8% or less, respectively. If the solids content of the CNF solutions was high and the fibrillation level was low, plugging was experienced in the spray head because of the high viscosity of the suspensions, resulting in production of poor-quality powders. In terms of reduction in processing energy, even if the CNF suspension solids content was increased to 1.5 wt.%, the powder quality and the production yields were excellent. It was confirmed that high-quality powder under 20 µm were produced at a 90% fibrillation level of all CNF feedstocks. The resulting dry CNF powders were characterized to determine particle size distributions and morphological properties via a scanning electron microscope and a laser diffraction particle size analyzer. The particle sizes were smaller at higher fibrillation levels and lower solids content of the CNF suspensions. The CNF suspension derived from bleached kraft pulp, the average particle size decreased by 43% and 33% with the lowered solids contents from 1.8 to 1%, and the increased fineness levels from 80 to 100%, respectively.

Improving Recycled Paper Materials through the Incorporation of Hemp, Wood Virgin Cellulose Fibers, and Nanofibers

A significant increase in the consumption of recycled fiber products has been observed worldwide, and the industry is forced to solve the challenges of recycled fiber quality and add strength agents and/or virgin fibers to reach sufficient properties. In order to investigate whether the mechanical and air permeability properties of waste fiber (WF) material can be significantly improved by adding wood kraft fibers (KF), hemp soda fibers (HF), and ammonium persulfate oxidated cellulose nanofibrils (CNF), different fiber blends were prepared and tested. Results revealed the excellence of hemp fibers over wood fibers regarding the improvement of WF products. The results of WF after the addition of 10% mixed fibers (KF + HF) were higher than the results of a 50% KF addition. The impact of CNF depended on fiber composition and properties. A formula for modeling the CNF impact on different fiber compositions was proposed. Obtained fiber material samples showed suitability for home composting, thus contributing to the goals of the European Green Deal regarding reducing landfill waste and the development of cleaner products.

Nanoemulsion-integrated gelatin/bacterial cellulose nanofibril-based multifunctional film: Fabrication, characterization, and application

The current requirements of food safety regulations and the environmental impact stemming from plastic packaging can only be addressed by developing suitable bio-nanocomposite films. Therefore, this study is dedicated to the fabrication of multifunctional film composed of gelatin, bacterial cellulose nanofibrils (BCNF), and black pepper essential oil nanoemulsion (BPEONE) and application for duck meat preservation. BCNF was prepared through ultrasonication of cellulose derived from Komagataeibacter xylinus. BPEONE observed spherical morphology with a diameter ranging from 83.7 to 118 nm. A film matrix containing a higher gelatin proportion than BCNF was more effective in trapping BPEONE. However, increasing the BPEONE fraction showed more surface abrasion and voids in the film morphology. A flexible film with good interaction, crystallinity, and greater thermal stability (421 °C) was developed. Nevertheless, film hydrophobicity (118.89°) declined, resulting in a notable effect on water solubility, swelling, and water vapor permeability. Moreover, the film had improved antibacterial and antioxidant activities, coupled with controlled release characteristics. Consequently, the developed film effectively retarded the lipid oxidation, inhibited microbial growth, and extended the shelf life of duck meat at refrigeration (4 °C) by 3 days, and made the film a promising alternative in the realm of bio-active packaging technology.

Aldehyde modified nanocellulose-based fluorescent hydrogel toward multistage data security encryption

In view of the insecurity of encode information storage based on fluorescence switch single-stage encryption, a fluorescent hydrogel for multistage data security encryption were proposed, named as polyvinyl alcohol/dialdehyde cellulose nanofibrils/carbon quantum dots hydrogel. Herein, the interpenetrating network was formed by chemically crosslinking between polyvinyl alcohol (PVA) and dialdehyde cellulose nanofibrils (DACNF). Additionally, nitrogen-doped carbon quantum dots (CDs) synthesized by one-step hydrothermal method were introduced into the above hydrogel system by hydrogen bonds. The resultant fluorescent hydrogels possessed high stretchability up to 530 %, good strength of 0.96 MPa, Fe3+-responsive fluorescence quenching, fluorescence recovery triggered by ascorbic acid and borax-triggered shape memory. Moreover, various complex 3D hydrogel geometries were fabricated by folding/assembling 2D fluorescent hydrogel sheets, extending data encryption capability from 2D plane to 3D space. More remarkably, the 3D data encryption-erasing process of fluorescent hydrogel was realized by the strategy of alternating treatment of Fe3+ solution and ascorbic acid solution. This work provided a facile and general strategy for constructing high security important information encryption and protection.