Enhanced rheology and firefighting performance of fluorine-free soft foams through the assembly of cellulose nanofibres and cellulose nanocrystals at the air-liquid interface.

In this work, we developed soft and highly stable perfluorocarbon-free foams based on cellulose nanofibres (CNFs), cellulose nanocrystals (CNCs) and alkyl polyglycoside (APG). Neither the CNCs nor the CNFs can effectively stabilise the APG foam, which is reflected in the spontaneous degradation of the foam. Interestingly, blending these two nanocelluloses and foaming resulted in an ultrastable foam. The reflective optical interference technique was used to visualise liquid flow in the liquid film, and the results showed that the foam film with a thickness of only a few tens of nanometres gained excellent mechanical stability by tuning the assembly of CNCs and CNFs at the air-liquid interface. Moreover, the interfibril interactions at the Plateau borders reduce the bubble coarsening rate and drainage rate. In pool fire extinguishing tests, increasing the total concentration of CNCs and CNFs improved the foam stability, but increasing the viscosity led to a decrease in the foam spreading rate. Thus, a formulation with 0.4 % nanocellulose has poorer firefighting performance than a formulation with 0.15 % nanocellulose. When the ratios of CNCs and CNFs are properly controlled, the burnback performance of perfluorocarbon-free foam is better than that of state-of-the-art fluorinated AFFFs for n-heptane pool fires. The sustainability of the firefighting process is considerably improved by switching to the nonperfluorinated liquid foam developed in this work.

BACTERIAL NANOCELLULOSE DRESSING COMPARED WITH HYDROCOLLOID DRESSING FOR THE TREATMENT OF PARTIAL-THICKNESS SECOND-DEGREE BURNS: A PROSPECTIVE, RANDOMIZED CONTROL TRIAL.

The management of burn wounds is a major challenge throughout the globe. Superficial and partial-thickness burns generally do not need any surgical intervention, however, severe cases of burn injury require dressings (antimicrobial) and surgery in the worst-case scenario. The present study was conducted to assess the efficacy of bacterial nanocellulose dressing versus hydrocolloid dressing. All patients presenting with partial-thickness second-degree burns from June 2021 to May 2022 were screened for this randomized control trial; 65 burn patients were included in each group of this trial. The control group of patients was treated with hydrocolloid dressing and the experimental group with bacterial nanocellulose dressing sheets. Every third day, the wound was assessed. Other data collected included age, sex, %TBSA burned, signs of infection, time for epithelialization, and length of hospital stay. Statistical analyses were performed to see the significance of differences between the treatment groups by adjusting for size and depth of burn, and the patient's age. There were 130 patients (65 in each group). The median age for the whole group was 17.4 years, and 51.53% (n=67) were males. The average TBSA was 22.4%, with a minimum of 10% and a maximum of 31%. Eleven of the patients had their burns excised, and four were given skin grafts in the control group. In the case of the experimental group, four excisions were performed, and one skin graft. Wound-related pain scores were low (mean of 2.6) for the bacterial nanocellulose group and higher for the hydrocolloid group. Hydrocolloid dressing is more cost effective than bacterial nanocellulose dressing. However, the pain scores were high, and healing time was less in the bacterial nanocellulose group. Moreover, the hydrocolloid group is more prone to infection due to frequent dressing changes.

La prise en charge des brûlés est un problème mondial de santé publique. Si les brûlures superficielles et intermédiaires guérissent habituellement spontanément, les plus sévères nécessitent une prise en charge chirurgicale, après pansements antibactériens. Cette étude a pour but de comparer l'efficacité des pansements à l'hydrocellulose bactérien et l'hydrocolloïde. Tous les patients souffrant de brûlures intermédiaires vus entre juin 2021 et mai 2022 ont été tirés au sort pour former 2 groupes de 65, de 17,4 ans d'âge médian avec une légère prédominance masculine (67 soit 51,53%), brûlés sur 22,4% de SCT en moyenne (10-31). Le groupe contrôle avait des pansements à l'hydrocolloïde (HC), le groupe à l'étude au nanocellulose bactérien (NB), la plaie étant évaluée tous les 3 jours. Les variables à l'étude étaient l'âge, le sexe, la surface brûlée, les signes d'infection, le délai d'épithélialisation et la durée de séjour. Les comparaisons ont été ajustées sur la surface, la profondeur et l'âge. Dans le groupe HC, 11 patients ont été excisés et 4 greffés contre 4 et 1 dans le groupe NB. La douleur des NB était à 2,6 ; elle était plus élevée dans le groupe HC. Le NB est plus cher que le HC. Il faut toutefois rapporter ce coût à une douleur moindre et à une cicatrisation plus rapide. Qui plus est, les patients sous HC sont plus à risque d'infection en raison de changements de pansements plus fréquents.

Strong, tough self-healing multi-functional sodium alginate-based edible composite coating for banana preservation.

Edible coatings are a new green technology for preventing the rotting of fruits and extending their shelf lives. However, during storage, respiratory processes can generate large amounts of water, causing the dissolution of these coating. Furthermore, these coating can be mechanically damaged. Therefore, the development of strong, tough, waterproof and self-healing edible coatings is highly desirable. Herein, gluconolactone was slowly oxidized to generate gluconic acid, which was further used to protonate amino groups in wheat gluten (WG), forming strong electrostatic interactions, hydrogen bonds and ester bonds between soy hull nanocellulose (SHNC) and sodium alginate (SA). The introduction of WG and SHNC improved the mechanical strength, hydrophobicity and water retention of the composite film from 28 MPa, 33.2° ± 1.18° and 19.43° ± 0.83° to 60 MPa, 45.13° ± 1.53° and 41.47° ± 0.96°, respectively. Further, the composite film exhibited excellent self-healing, UV resistance and gas-barrier properties. Banana preservation experiments showed that at 25 °C and 50 % RH, the composite coating effectively slowed the mass loss and softening of bananas, delayed the browning of banana peels and ripening of fruit pulp, and extended the shelf life of bananas to 7 days. Therefore, this study provides a new perspective for the preparation of a new, strong, tough, waterproof and self-healing multi-functional edible coating with high potential for the preservation of perishable fruits.

3D structural analysis of the biodegradability of banana pseudostem nanocellulose bioplastics.

X-Ray micro-computed tomography (XCT) is used to reveal the micro-structural changes of banana pseudostem nanocellulose bioplastic due to a biodegradation process initiated in a formulated composting media that allowed the growth of aerobic microflora. The bioplastic itself was made of nanocellulose, which was isolated from banana pseudostem using the 2,2,6,6-Tetramethyl-1-piperidinyloxy (TEMPO) mediated oxidation method, and polyethylene glycol (PEG) as plasticiser. XCT provided insights into the 3D structural change of the bioplastic identifying the degradation process at two scales. The results showed that the local thickness and roughness of the bioplastic increased after degradation, while the density of the material decreased. Enlarged voids and tunnels were observed in the material after degradation. The formation of these tunnels is attributed to the popping of internal PEG-containing voids because of the generation of gases, which after forming may further accelerate biodegradation by microbial activity.

PLA based biodegradable bionanocomposite filaments reinforced with nanocellulose: development and analysis of properties.

The 3D printing technique has recently become more prevalent among researchers for the fabrication of nanocomposites. The low crystallinity of polylactic acid (PLA) leads to the poor mechanical and thermal properties of its 3D-printed products, which restrict their applications in many fields. To overcome the limitations of PLA, the present work aims to develop PLA-based bionanocomposite filaments with varying percentages (1, 3, and 5 wt%) of crystalline nanocellulose (CNC) through a single screw extruder. The filaments will be further utilized for the development of bionanocomposite samples to evaluate their properties. The effect of CNC reinforcement on the chemical structure of the filaments was analyzed by FTIR analysis. XRD analysis revealed that the crystallinity of the filaments was significantly improved due to the nucleating effect of CNC. The maximum crystallinity was observed in the filament containing 1 wt% CNC, which was 26% higher than the pure PLA filament. The thermal and mechanical performance of the filaments was also considerably improved after CNC reinforcement, which was confirmed by DSC-TGA and tensile test analysis. The maximum tensile strength and tensile modulus were observed to be 48.9 MPa and 1700 MPa, respectively, in the filament reinforced with 1 wt% CNC, which was 35.5% and 21.89%, respectively, higher than those of the pure PLA filament. Rheological analysis showed that the complex viscosity, storage modulus, and loss modulus of the filaments were significantly affected by the reinforcement of CNC.

Fabrication of bamboo nanocellulose fibril-based food packaging with dual-antimicrobial property.

The development of cellulose-based packaging films with excellent antimicrobial properties and biocompatibility has garnered significant attention. In this work, nanocellulose fibrils (NCFs) derived from from bamboo parenchyma cells were utilized to fabricate nanocomposite film with antimicrobial properties. This system exhibited distinct release behaviors for two antimicrobial agents, with the slow release of Ag nanoparticle (AgNP) in the initial stage contributed to delaying food spoilage, while the subsequent pH change in the microenvironment facilitated the release of essential oil of sour orange blossoms (SEO) for secondary antimicrobial activity. Additionally, the composite film demonstrated improved thermal stability and UV blocking capacity. Moreover, AgNP has been proven to enhance the mechanical properties, with the tensile strength of the novel composite film increasing by 34.85 % compared to control group. The water vapor permeability and oxygen permeability of the novel composite film were reduced, which could potentially reduce weight loss and slow down the rate of after-ripening. Following the acidification treatment, the films containing EO@MPN (essential oil encapsulated with metal-polyphenol network) component performed different antimicrobial patterns, indicating their pH-responsive antimicrobial capabilities, and they are effective against both Gram-positive and Gram-negative bacteria. After a 24-h exposure to a food simulant, the release amount of Ag was measured at 67.6 µg/dm2, within the acceptable limit, and the release profile of Ag was characterized. Cytotoxicity and Live/Dead staining tests confirmed that the novel composite film film had no significant toxicity, thus making it safe for application in food preservation. Furthermore, in a 15-day preservation experiment with mangoes, the novel composite film demonstrated the best performance, underscoring its potential as a sustainable antimicrobial packaging material.

Valorization of citrus peel industrial wastes for facile extraction of extractives, pectin, and cellulose nanocrystals through ultrasonication: An in-depth investigation.

In this work we developed an eco-friendly valorisation of Citrus wastes (CWs), through a solvent-assisted ultrasonication extraction technique, thus having access to a wide range of bio-active compounds and polysaccharides, extremely useful in different industrial sectors (food, cosmetics, nutraceutical). Water-based low-amplitude ultrasonication was examined as a potential method for pectin extraction as well as polar and non-polar citrus extractives (CEs), among which hesperidin and triglycerides of 18 carbon fatty acids were found to be the most representative ones. In addition, citric acid:glycerol (1:4)-based deep eutectic solvent (DES) in combination with ultrasonic extraction was utilized to extract microcellulose (CMC), from which stable cellulose nanocrystals (CNCs) with glycerol-assisted high amplitude ultrasonication were obtained. The physical and chemical properties of the extracted polysaccharides (pectin, micro and nanocellulose) were analysed through DLS, ζ-potential, XRD, HP-SEC, SEM, AFM, TGA-DSC, FTIR, NMR, and PMP-HPLC analyses. The putative structure of the extracted citrus pectin (CP) was analysed and elucidated through enzyme-assisted hydrolysis in correlation with ESI-MS and monosaccharide composition. The developed extraction methods are expected to influence the industrial process for the valorisation of CWs and implement the circular bio-economy.

Designing for Degradation: Transient Devices Enabled by (Nano)Cellulose.

Transient technology involves materials and devices that undergo controlled degradation after a reliable operation period. This groundbreaking strategy offers significant advantages over conventional devices based on non-renewable materials by limiting environmental exposure to potentially hazardous components after disposal, and by increasing material circularity. As the most abundant naturally occurring polymer on Earth, cellulose is an attractive material for this purpose. Besides, (nano)celluloses are inherently biodegradable and have competitive mechanical, optical, thermal, and ionic conductivity properties that can be exploited to develop sustainable devices and avoid the end-of-life issues associated with conventional systems. Despite its potential, few efforts have been made to review current advances in cellulose-based transient technology. Therefore, this review catalogs the state-of-the-art developments in transient devices enabled by cellulosic materials. To provide a wide perspective, the various degradation mechanisms involved in cellulosic transient devices are introduced. The advanced capabilities of transient cellulosic systems in sensing, photonics, energy storage, electronics, and biomedicine are also highlighted. Current bottlenecks toward successful implementation are discussed, with material circularity and environmental impact metrics at the center. It is believed that this review will serve as a valuable resource for the proliferation of cellulose-based transient technology and its implementation into fully integrated, circular, and environmentally sustainable devices.

Fabrication of edible nanocellulose chitosan bi-component film based on a novel "swell-permeate" approach.

The fabrication of multi-component film with colloidal particles could be inconvenient. A novel "swell-permeate" (SP) strategy was proposed to form homogeneous multi-component films. The SP strategy allows colloidal particles to fit into the polymer network by stretching the polymer chains assisted by water. We demonstrated the strategy by creating films with polysaccharide substrates as ß-cyclodextrin grafted chitosan (CS) with nanocellulose. The addition of nanocellulose significantly increased the mechanical properties and the barrier performance of the films. The size of nanocellulose particles in affecting mechanical properties was investigated by applying different length of cellulose nanocrystal (CNC), the longer of which, due to denser physical entanglements, showed a better increase to the film in the elastic modulus and tensile strength to 4.54-fold and 5.71-fold, respectively. The films were also loaded with ethyl-p-coumarate (EpCA) and had an enhanced performance in anti-microbial for Altenaria alternata, Salmonella typhi, and Escherichia coli. The anti-oxidative property was increased as well, and both effects were valid both in vitro and in ready-to-eat apples. The strategy provides a practical and convenient method for fabricating colloidal particle containing films, and the novel idea of "swell-permeate" is potentially regarded as a new solution to the challenge of ready-to-eat food quality maintenance.

Gas evolution in self-extinguishing and insulative nanopolysaccharide-based hybrid foams.

Lightweight, energy-efficient materials in building construction typically include polymeric and composite foams. However, these materials pose significant fire hazards due to their high combustibility and toxic gas emissions, including carbon monoxide and hydrogen cyanide. This study delves into the latter aspects by comparing hybrid systems based on nanofiber-reinforced silica-based Pickering foams with a synthetic reference (polyurethane foams). The extent and dynamics of fire retardancy and toxic gas evolution were assessed, and the results revealed the benefits of combining the thermal insulation of silica with the structural strength of biobased nanofibers, the latter of which included anionic and phosphorylated cellulose as well as chitin nanofibers. We demonstrate that the nanofiber-reinforced silica-based Pickering foams are thermal insulative and provide both fire safety and energy efficiency. The results set the basis for the practical design of hybrid foams to advance environmental sustainability goals by reducing energy consumption in built environments.

Investigate the in vitro biocompatibility, biodegradation, cytotoxicity, and differentiation potential of 3-D gelatin-nanocellulose composite scaffolds loaded with nanohydroxyapatite and simvastatin.

Bone tissue engineering has been proposed as a promising solution for healing of bone fractures. An important aspect of bone tissue engineering is the implantable scaffolds that participate in the regeneration and repair of bone tissue. In this study, the composite scaffolds of gelatin- nanocellulose loaded with nanohydroxyapatite and simvastatin (as the osteoinductive component) were fabricated using freeze- drying method. Scaffolds were characterized in terms of morphology, mechanical, biodegradability, water absorption capacity, and simvastatin release characteristics. Also, the biocompatibility and differentiation potential of the scaffolds were evaluated on human bone marrow-derived mesenchymal stem cells using the MTT assay and alizarin red staining, respectively. The simvastatin loaded scaffolds showed a sustained release profile in vitro up to 216 h. The results of BMSCs differentiation by alizarin red staining showed significant differences between the simvastatin loaded group and other groups. Moreover, the results of MTT assay verified cytocompatibility and non-toxicity of the scaffolds. Therefore, the gelatin-nano cellulose composite scaffolds loaded with hydroxyapatite and simvastatin may be considered promising for use in bone tissue engineering.

Modulating the isotopic hydrogen-deuterium exchange in functionalized nanocellulose to optimize SANS contrast.

Contrast matching by isotopic exchange in cellulose allows visualizing functional groups, biomolecules, polymers and nanoparticles embedded in cellulosic composites. This isotopic exchange varies the scattering length density of cellulose to match its contrast with the background network. Here, contrast matching of microcrystalline-cellulose (MCC) and the functionalized nanocellulose-fiber (CNF) and cellulose nanocrystals (CNC) are elucidated by small angle neutron scattering (SANS). Results show no isotopic exchange occurs for the CNF surface functionalized with carboxyl nor for the CNC-High with a high sulfate groups concentration. Both CNC-Low, with low sulfate groups, and MCC exchange 1H with 1D in D2O. This is due to the high exchange probability of the labile C6 position primary -OH group. The structure of thermo-responsive poly-N-isopropylacrylamide (PNIPAM) chains grafted onto CNF (PNIPAM-grafted-CNF) was extracted by CNF contrast matching near the lower critical solution temperature. Contrast matching eradicates the CNF scattering to retain only the scattering from the grafted-PNIPAM chains. The coil to globule thermo-transition of PNIPAM was revealed by the power law variation from q-1.3 to q-4 in SANS. Isotopic exchange in functionalized cellulosic materials reveals the nano- and micro-scale structure of its individual components. This improved visualization by contrast matching can be extended to carbohydrate polymers to engineer biopharmaceutical and food applications.

Nanocellulose in targeted drug delivery: A review of modifications and synergistic applications.

Nanocellulose, a versatile biopolymer renowned for its exceptional physicochemical attributes including lightweight, biocompatibility, biodegradability, and higher mechanical strength properties has captured significant attention in biomedical research. This renewable material, extracted from widely abundant biosources including plants, bacteria, and algae, exists in three primary forms: cellulose-based nanocrystals (CNCs), nanofibrils (CNFs), and bacterial nanocellulose (BNC). CNCs are characterized by their highly crystalline, needle-shaped structure, while CNFs possess a blend of amorphous and crystalline regions. BNC stands out as the purest form of nanocellulose. Chemical functionalization enables precise tuning of nanocellulose properties, enhancing its suitability for diverse biomedical applications. In drug delivery systems, nanocellulose's unique structure and surface chemistry offer opportunities for targeted delivery of active molecules. Surface-modified nanocellulose can effectively deliver drugs to specific sites, utilizing its inherent properties to control drug release kinetics and improve therapeutic outcomes. Despite these advantages, challenges such as achieving optimal drug loading capacity and ensuring sustained drug release remain. Future research aims to address these challenges and explore novel applications of nano-structured cellulose in targeted drug delivery, highlighting the continued evolution of this promising biomaterial in biomedicine. Furthermore, the review delves into the impact of chemical, physical, and enzymatic methods for CNC surface modifications, showcasing how these approaches enhance the functionalization of CNCs for targeted delivery of different compounds in biological systems.

Advanced functional materials based on nanocellulose/Mxene: A review.

The escalating need for a sustainable future has driven the advancement of renewable functional materials. Nanocellulose, derived from the abundant natural biopolymer cellulose, demonstrates noteworthy characteristics, including high surface area, crystallinity, mechanical strength, and modifiable chemistry. When combined with two-dimensional (2D) graphitic materials, nanocellulose can generate sophisticated hybrid materials with diverse applications as building blocks, carriers, scaffolds, and reinforcing constituents. This review highlights the progress of research on advanced functional materials based on the integration of nanocellulose, a versatile biopolymer with tailorable properties, and MXenes, a new class of 2D transition metal carbides/nitrides known for their excellent conductivity, mechanical strength, and large surface area. By addressing the challenges and envisioning future prospects, this review underscores the burgeoning opportunities inherent in MXene/nanocellulose composites, heralding a sustainable frontier in the field of materials science.

Characterization of Alginate-Crystalline Nanocellulose Composite Hydrogel as Polyphenol Encapsulation Agent.

Alginate hydrogel is broadly known for its potential as an encapsulation agent due to its compatibility and versatility. Despite its predominance, alginate hydrogel naturally has macropores and a less rigid structure, which leads to syneresis and uncontrolled diffusion of bioactive compounds from the gel network. Combining alginate with other biopolymers has been considered to improve its properties as an encapsulation agent. This research aimed to evaluate the effect of Crystalline Nanocellulose (CNC) to the physical properties and the diffusion of gallic acid (GA), as a water-soluble polyphenol model, through the alginate-CNC composite hydrogels performed as an encapsulation agent. The hydrogel mixtures were made from 1:0, 1:1, 2:0, 2:1, 2:2, and 2:3 solid-basis ratio of sodium alginate:crystalline nanocellulose and evaluated for syneresis, gel strength and stiffness, rehydration properties and gel porosity. Alginate-CNC and GA interaction was observed through zeta-potential analysis and Fourier Transform Infrared (FTIR) spectroscopy. Results showed that composite hydrogel with the highest proportion of CNC increased the gel rehydration capacity (87.33 %), gel strength and stiffness as well as reduced the gel syneresis (14.72 %) and dried gel porosity (0.62). GA pre-loaded gel with 2:2 and 2:3 S-C ratios reduced the diffusion of gallic acid by 92.07-92.27 %. FTIR showed hydrogen bonding between GA and the alginate-CNC hydrogel. Alginate-CNC hydrogel had a fibrous and compact structure as shown in the cryo-SEM and confocal microscope images.

Plasma Treatment of Nanocellulose to Improve the Surface Properties.

Nanocellulose is among the most promising materials for enhancing the mechanical properties of polymer composites. Broad application is, however, limited by inadequate surface properties. A standard technique for tailoring the surface composition and wettability of polymers is a brief treatment with non-equilibrium gaseous plasma, but it often fails when treating materials with a large surface-to-mass ratio, such as cellulose nanofibers. In this paper, the theoretical limitations are explained, the approaches reported by different groups are reviewed, and the results are interpreted. The treatment of dry nanocellulose is limited by the ability of uniform treatment, whereas the plasma treatment of nanocellulose dispersed in liquids is a slow process. The methods for enhancing the treatment efficiency for both dry and water-dispersed nanocellulose are explained.

Effect of Antisolvent Used to Regenerate Cellulose Treated with Ionic Liquid on Its Properties.

The solvolysis reaction with ionic liquids is one of the most frequently used methods for producing nanometer-sized cellulose. In this study, the nanocellulose was obtained by reacting microcrystalline cellulose with 1-ethyl-3-methylimidazolium acetate (EmimOAc). The aim of this research was to determine the influence of various antisolvents used in the regeneration of cellulose after treatment with ionic liquid on its properties. The following antisolvents were used in this research: acetone, acetonitrile, water, ethanol and a mixture of acetone and water in a 1:1 v/v ratio. The nanocellulose was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM) and elemental analysis (EA). The results show that the antisolvent used to regenerate cellulose after the solvolysis reaction with EmimOAc affects its properties. Water, ethanol and a mixture of acetone and water successfully removed the used ionic liquid from the cellulose structure, while acetone and acetonitrile were unable to completely remove EmimOAc from the cellulosic material. The results of the XRD analysis indicate that there is a correlation between the ionic liquid content in the regenerated cellulose and its degree of crystallinity. Among the tested solvents, water leads to the effective removal of EmimOAc from the cellulose structure, which is additionally characterized by the smallest particle size and non-formation of agglomerates.

From cane to nano: advanced nanomaterials derived from sugarcane products with insights into their synthesis and applications.

Sugarcane-based products are inherently rich in elements such as silicon, carbon and nitrogen. As such, these become ideal precursors for utilization in a wide array of application fields. One of the appealing areas is to transform them into nanomaterials of high interest that can be employed in several prominent applications. Among nanomaterials, sugarcane products based on silica nanoparticles (SNPs), carbon dots (CDs), metal/metal oxide-based NPs, nanocellulose, cellulose nanofibers (CNFs), and nano biochar are becoming increasingly reported. Through manipulation of the experimental conditions and choosing suitable starting precursors and elements, it is possible to devise these nanomaterials with highly desired properties suited for specific applications. The current review presents the findings from the recent literature wherein an effort has been made to convey new development in the field of sugarcane-based products for the synthesis of the above-mentioned nanomaterials. Various nanomaterials were systematically discussed in terms of their synthesis and application perspectives. Wherever possible, a comparative analysis was carried out to highlight the potential of sugarcane products for the intended purpose as compared to other biomass-based materials. This review is expected to stand out in delivering an up-to-date survey of the literature and provide readers with necessary directions for future research.

This review focuses on sugarcane-derived nanomaterials such as silica, nano cellulose, nanofibers, nanocrystals and metal/nonmetal nanoparticles and their application in various energy and environmental fields.

Responsive nanocellulose-PNIPAM millicapsules.

HYPOTHESIS: Milli- and micro-capsules are developed to facilitate the controlled release of diverse active ingredients by passive diffusion or a triggered burst. As applications expand, capsules are required to be increasingly multi-functional, combining benefits like encapsulation, response, release, and even movement. Balancing the increasingly complex demands of capsules is a desire to minimize material usage, requiring efficient structural and chemical design. Designing multifunctional capsules with complex deformation should be possible even after minimizing the material usage through use of sparse fiber networks if the fibers are coated with responsive polymers. EXPERIMENTS: Here capsules are created with a shell made from a mesh of nanoscale bacterial cellulose fibers that provide mechanical strength at very low mass levels, while a coating of thermoresponsive Poly(N-isopropylacrylamide), PNIPAM, on the fibers provides control of permeability, elastic response, and temperature response. These properties are varied by grafting different amounts of polymer using particular reaction conditions. FINDINGS: The addition of PNIPAM to the cellulose mesh capsule enhances its mechanical properties, enabling it to undergo large deformations and recover once stress is removed. The increased elastic response of the capsule also provides reinforcement against drying-induced capillary stresses, limiting the degree of shrinkage during dehydration. Time-lapse microscopy demonstrates thermoreversible swelling of the capsules in response to temperature change. Cycles of swelling and shrinkage drive solvent convection to and from the capsule interior, allowing exchange of contents and mixing with the bulk fluid on a time scale of seconds. Because the cellulose capsules are produced via emulsion-templated fermentation, the polymer-modified biocapsule concept introduced here presents a pathway toward the sustainable and scalable manufacture of multifunctional responsive capsules.

Synthesis of hemostatic aerogel of TEMPO-oxidized cellulose nanofibers/collagen/chitosan and in vivo/vitro evaluation.

The treatment of internal hemorrhage remains challenging due to the current limited antibacterial capability, hemostatic efficacy, and biocompatibility of hemostatic materials. The TEMPO-oxidized cellulose nanofibers/collagen/chitosan (TCNF/COL/CS) hemostatic aerogel was developed in this work by physically encasing COL in a sandwich structure and electrostatically self-assembling polyanionic TCNF with polycationic CS. In vitro coagulation experiments revealed the favorable procoagulant properties of TCNF/COL/CS along with high adhesion to erythrocytes and platelets. TCNF/COL/CS significantly increased the hemostatic efficacy by 59.8 % and decreased blood loss by 62.2 % in the liver injury model when compared to Surgicel®, the most frequently used hemostatic material. Furthermore, it demonstrated outstanding biodegradability both in vitro and in vivo, and a substantial increase in resistance (96.8 % against E. coli and 95.4 % against S. aureus) compared to TCNF. The significant hemostatic and biodegradable characteristics of TCNF/COL/CS can be ascribed to its interconnected porous structure, increased porosity, and efficient water absorption, along with the synergistic effect of the three constituents. The TCNF/COL/CS aerogel shows significant potential to control internal bleeding. A novel plant-derived nanocellulose composite aerogel has been described here for the first time; it has outstanding antibacterial characteristics, higher biocompatibility, and outstanding hemostatic characteristics in vivo.