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1.
Proc Natl Acad Sci U S A ; 119(24): e2200930119, 2022 06 14.
Artículo en Inglés | MEDLINE | ID: mdl-35671425

RESUMEN

Biological functionality is often enabled by a fascinating variety of physical phenomena that emerge from orientational order of building blocks, a defining property of nematic liquid crystals that is also pervasive in nature. Out-of-equilibrium, "living" analogs of these technological materials are found in biological embodiments ranging from myelin sheath of neurons to extracellular matrices of bacterial biofilms and cuticles of beetles. However, physical underpinnings behind manifestations of orientational order in biological systems often remain unexplored. For example, while nematiclike birefringent domains of biofilms are found in many bacterial systems, the physics behind their formation is rarely known. Here, using cellulose-synthesizing Acetobacter xylinum bacteria, we reveal how biological activity leads to orientational ordering in fluid and gel analogs of these soft matter systems, both in water and on solid agar, with a topological defect found between the domains. Furthermore, the nutrient feeding direction plays a role like that of rubbing of confining surfaces in conventional liquid crystals, turning polydomain organization within the biofilms into a birefringent monocrystal-like order of both the extracellular matrix and the rod-like bacteria within it. We probe evolution of scalar orientational order parameters of cellulose nanofibers and bacteria associated with fluid-gel and isotropic-nematic transformations, showing how highly ordered active nematic fluids and gels evolve with time during biological-activity-driven, disorder-order transformation. With fluid and soft-gel nematics observed in a certain range of biological activity, this mesophase-exhibiting system is dubbed "biotropic," analogously to thermotropic nematics that exhibit solely orientational order within a temperature range, promising technological and fundamental-science applications.


Asunto(s)
Celulosa , Gluconacetobacter xylinus , Cristales Líquidos , Celulosa/biosíntesis , Celulosa/química , Geles , Gluconacetobacter xylinus/metabolismo , Cristales Líquidos/química , Agua/química
2.
Proc Natl Acad Sci U S A ; 119(42): e2117467119, 2022 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-36215467

RESUMEN

Protein adsorption to solid carbohydrate interfaces is critical to many biological processes, particularly in biomass deconstruction. To engineer more-efficient enzymes for biomass deconstruction into sugars, it is necessary to characterize the complex protein-carbohydrate interfacial interactions. A carbohydrate-binding module (CBM) is often associated with microbial surface-tethered cellulosomes or secreted cellulase enzymes to enhance substrate accessibility. However, it is not well known how CBMs recognize, bind, and dissociate from polysaccharides to facilitate efficient cellulolytic activity, due to the lack of mechanistic understanding and a suitable toolkit to study CBM-substrate interactions. Our work outlines a general approach to study the unbinding behavior of CBMs from polysaccharide surfaces using a highly multiplexed single-molecule force spectroscopy assay. Here, we apply acoustic force spectroscopy (AFS) to probe a Clostridium thermocellum cellulosomal scaffoldin protein (CBM3a) and measure its dissociation from nanocellulose surfaces at physiologically relevant, low force loading rates. An automated microfluidic setup and method for uniform deposition of insoluble polysaccharides on the AFS chip surfaces are demonstrated. The rupture forces of wild-type CBM3a, and its Y67A mutant, unbinding from nanocellulose surfaces suggests distinct multimodal CBM binding conformations, with structural mechanisms further explored using molecular dynamics simulations. Applying classical dynamic force spectroscopy theory, the single-molecule unbinding rate at zero force is extrapolated and found to agree with bulk equilibrium unbinding rates estimated independently using quartz crystal microbalance with dissipation monitoring. However, our results also highlight critical limitations of applying classical theory to explain the highly multivalent binding interactions for cellulose-CBM bond rupture forces exceeding 15 pN.


Asunto(s)
Celulasa , Clostridium thermocellum , Acústica , Proteínas Bacterianas/metabolismo , Carbohidratos/química , Celulasa/metabolismo , Celulosa/metabolismo , Clostridium thermocellum/metabolismo , Análisis Espectral , Azúcares
3.
Nano Lett ; 24(21): 6262-6268, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38743501

RESUMEN

Expanding the interlayer spacing plays a significant role in improving the conductivity of a cellulose-based conductor. However, it remains a challenge to regulate the cellulose nanochannel expanded by ion coordination. Herein, starting from multiscale mechanics, we proposed a strain engineering method to regulate the interlayer spacing of the cellulose nanochannels. First-principles calculations were conducted to select the most suitable ions for coordination. Large-scale molecular dynamics simulations were performed to reveal the mechanism of interlayer spacing expansion by the ion cross-linking. Combining the shear-lag model, we established the relationship between interfacial cross-link density and interlayer spacing of an ion-coordinated cellulose nanochannel. Consequently, fast ion transport and current regulation were realized via the strain engineering of nanochannels, which provides a promising strategy for the current regulation of a cellulose-based conductor.

4.
Small ; : e2403947, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38948958

RESUMEN

Converting hierarchical biomass structure into cutting-edge architecture of electrocatalysts can effectively relieve the extreme dependency of nonrenewable fossil-fuel-resources typically suffering from low cost-effectiveness, scarce supplies, and adverse environmental impacts. A cost-effective cobalt-coordinated nanocellulose (CNF) strategy is reported for realizing a high-performance 2e-ORR electrocatalysts through molecular engineering of hybrid ZIFs-CNF architecture. By a coordination and pyrolysis process, it generates substantial oxygen-capturing active sites within the typically oxygen-insulating cellulose, promoting O2 mass and electron transfer efficiency along the nanostructured Co3O4 anchored with CNF-based biochar. The Co-CNF electrocatalyst exhibits an exceptional H2O2 electrosynthesis efficiency of ≈510.58 mg L-1 cm-2 h-1 with an exceptional superiority over the existing biochar-, or fossil-fuel-derived electrocatalysts. The combination of the electrocatalysts with stainless steel mesh serving as a dual cathode can strongly decompose regular organic pollutants (up to 99.43% removal efficiency by 30 min), showing to be a desirable approach for clean environmental remediation with sustainability, ecological safety, and high-performance.

5.
Small ; 20(14): e2305924, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37990391

RESUMEN

Flexible fibers and textiles featuring photothermal conversion and storage capacities are ideal platforms for solar-energy utilization and wearable thermal management. Other than using fossil-fuel-based synthetic fibers, re-designing natural fibers with nanotechnology is a sustainable but challenging option. Herein, advanced core-shell structure fibers based on plant-based nanocelluloses are obtained using a facile co-axial wet-spinning process, which has superior photothermal and thermal-regulating performances. Besides serving as the continuous matrix, nanocelluloses also have two other important roles: dispersing agent when exfoliating molybdenum disulfide (MoS2), and stabilizer for phase change materials (PCM) in the form of Pickering emulsion. Consequently, the shell layer contains well-oriented nanocelluloses and MoS2, and the core layer contains a high content of PCM in a leak-proof encapsulated manner. Such a hierarchical cellulosic supportive structure leads to high mechanical strength (139 MPa), favorable flexibility, and large latent heat (92.0 J g-1), surpassing most previous studies. Furthermore, the corresponding woven cloth demonstrates satisfactory thermal-regulating performance, high solar-thermal conversion and storage efficiency (78.4-84.3%), and excellent long-term performance. In all, this work paves a new way to build advanced structures by assembling nanoparticles and polymers for functional composite fibers in advanced solar-energy-related applications.

6.
Biopolymers ; : e23577, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38526043

RESUMEN

Bacterial nanocellulose (BNC) has various unique qualities, including high mechanical strength, crystallinity, and high water-holding capacity, which makes it appropriate for a wide range of industrial applications. But its lower yield coupled with its high production cost creates a barrier to its usage. In this study, we have demonstrated the better yield of BNC from an indigenous strain Komagataeibacter rhaeticus MCC-0157 using a rotary disc bioreactor (RDB) having a wooden disc. The RDB was optimized based on the type of disc material, distance between the disc, and rotation speed to get the highest yield of 13.0 g/L dry material using Hestrin-Schramm (H-S) medium. Further, the bioreactor was compared for the BNC production using reported medium, which is used for static condition; the RDB showed up to fivefold increase in comparison with the static condition reported. Komagataeibacter rhaeticus MCC-0157 was previously reported to be one of the highest BNC producing stains, with 8.37 g/L of dry yield in static condition in 15 days incubation. The designed RDB demonstrated 13.0 g/L dry yield of BNC in just 5 days. Other characteristics of BNC remain same as compared with static BNC production, although the difference in the crystallinity index was observed in RDB (84.44%) in comparison with static (89.74%). For the first time, wooden disc was used for rotary bioreactor approach, which demonstrated higher yield of BNC in lesser time and can be further used for sustainable production of BNC at the industrial level.

7.
Nanotechnology ; 35(38)2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38906121

RESUMEN

In the present study, pyroligneous acid, also known as wood vinegar, has been employed as reducing and stabilizing agent in the synthesis of silver nanoparticles (AgNPs) anchored on nanocellulose (NC). The idea is to confer the latter bactericidal properties for its typical uses such as in cosmetics and food-packing. It has been demonstrated that AgNPs can be directly produced onto NC in one-pot fashion while dramatically enhancing the kinetics of AgNPs synthesis (2 h for reaction completion) in comparison to the NC-less counterpart (10 days for reaction completion). Furthermore, NC allowed for a narrower size distribution of AgNPs. NC-supported and non-supported AgNPs had sizes of 5.1 ± 1.6 nm and 16.7 ± 4.62 nm, respectively. Immortalized human keratinocytes (HaCat) cells were then employed as model to evaluate the cytotoxicity of the AgNPs-NC compound. The latter was found not to impact cell proliferation at any formulation, while decreasing the viability by only 6.8% after 72 h. This study contributes to the development of more environmentally benign routes to produce nanomaterials and to the understanding of their impact on cells.


Asunto(s)
Supervivencia Celular , Celulosa , Células HaCaT , Nanopartículas del Metal , Plata , Humanos , Plata/química , Nanopartículas del Metal/química , Celulosa/química , Celulosa/farmacología , Supervivencia Celular/efectos de los fármacos , Queratinocitos/efectos de los fármacos , Queratinocitos/citología , Tamaño de la Partícula , Proliferación Celular/efectos de los fármacos , Ácido Acético/química , Ácido Acético/farmacología
8.
Macromol Rapid Commun ; : e2400098, 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38862122

RESUMEN

Cellulose nanopaper is a material structure that possess high mechanical performance and is widely regarded as a promising two-dimensional reinforcement for polymer matrix composites. This work explores the use of low grammage bacterial cellulose (BC) nanopaper as reinforcement for poly(acrylated urethane) interlayer adhesive to increase the impact performance of multi-layer acrylic composites. The BC nanopaper is impregnated with an acrylated urethane resin and laminated between acrylic sheets to create BC/acrylic composites consisting of one, three and five layers of BC nanopaper-reinforced poly(acrylated urethane) interlayer adhesive(s). Both the the poly(acrylated urethane)-filled BC nanopaper interlayer adhesive and the resulting laminated acrylic composites are optically transparent. The incorporation of BC nanopaper into the poly(acrylated urethane) interlayer adhesive improves the tensile modulus by eightfold and the single-edge notched fracture toughness by 60% compared to neat poly(acrylated urethane). It was also found that using poly(acrylated urethane)-filled BC nanopaper interlayer adhesive proved beneficial to the impact properties of the resulting laminated acrylic composites. In Charpy impact testing, the impact strength of the multi-layer acrylic composites increased by up to 130% compared to the "gold-standard" impact-modified monolithic acrylic, with a BC loading of only 1.6 wt.-%. This article is protected by copyright. All rights reserved.

9.
Environ Res ; 243: 117889, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38086501

RESUMEN

In the last decade, both cellulose and alginate polysaccharides have been extensively utilized for the synthesis of biocompatible hydrogels because of their alluring characteristics like low cost, biodegradability, hydrophilicity, biodegradability, ease of availability and non-toxicity. The presence of abundant hydrophilic functional groups (like carboxyl and hydroxyl) on the surface of cellulose and alginate or their derivatives makes these materials promising candidates for the preparation of hydrogels with appealing structures and characteristics, leading to growing research in water treatment and biomedical fields. These two polysaccharides are typically blended together to improve hydrogels' desired qualities (mechanical strength, adsorption properties, cellulose/alginate yield). So, keeping in view their extensive applicability, in the present review article, recent advances in the development of cellulose/nanocellulose-alginate-based hydrogels and their relevance in water treatment (adsorption of dyes, heavy metals, etc.) and biomedical field (wound healing, tissue engineering, drug delivery) has been reviewed. Further, impact of other inorganic/organic additives in cellulose/nanocellulose-alginate-based hydrogels properties like contaminants adsorption, drug delivery, tissue engineering, etc., has also been studied. Moreover, the current difficulties and future prospects of nanocellulose-alginate-based hydrogels regarding their water purification and biomedical applications are also discussed at the end.


Asunto(s)
Celulosa , Nanocompuestos , Celulosa/química , Alginatos , Hidrogeles/química , Polisacáridos/química
10.
Environ Res ; 257: 119231, 2024 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-38797468

RESUMEN

The persistent water treatment and separation challenge necessitates innovative and sustainable advances to tackle conventional and emerging contaminants in the aquatic environment effectively. Therefore, a unique three-dimensional (3D) network composite film (BNC-KC) comprised of bacterial nanocellulose (BNC) incorporated nano-kaolinite clay particles (KC) was successfully synthesized via an in-situ approach. The microscopic characterization of BNC-KC revealed an effective integration of KC within the 3D matrix of BNC. The investigated mechanical properties of BNC-KC demonstrated a better performance compared to BNC. Thereafter, the sorption performance of BNC-KC films towards basic blue 9 dye (Bb9) and norfloxacin (NFX) antibiotic from water was investigated. The maximum sorption capacities of BNC-KC for Bb9 and NFX were 127.64 and 101.68 mg/g, respectively. Mechanistic studies showed that electrostatic interactions, multi-layered sorption, and 3D structure are pivotal in the NFX/Bb9 sorption process. The intricate architecture of BNC-KC effectively traps molecules within the interlayer spaces, significantly increasing sorption efficiency. The distinctive structural configuration of BNC-KC films effectively addressed the challenges of post-water treatment separation while concurrently mitigating waste generation. The environmental evaluation, engineering, and economic feasibility of BNC-KC are also discussed. The cost estimation assessment of BNC-KC revealed the potential to remove NFX and Bb9 from water at an economically viable cost.

11.
Artículo en Inglés | MEDLINE | ID: mdl-38980386

RESUMEN

In this paper, the work has been done to develop a cost-effective methodology, for the isolation of the potential producer of bacterial nanocellulose. No report is available in the literature, on the use of gram flour and table sugar for the screening of nanocellulose-producing isolates. Since commercially used, Hestrin-Schramm medium is expensive for the isolation of nanocellulose-producing micro-organisms, the possibility of using gram flour-table sugar medium was investigated in this work. Qualitative screening of micro-organisms was done using cost-effective medium, i.e., gram flour-table sugar medium. Qualitative analysis of various nanocellulose-producing bacteria depicted that cellulose layer production occurred on both HS medium and gram flour-table sugar medium. The yield of nanocellulose was also better on air-liquid surface in case of gram flour-table sugar medium as compared to HS medium. 16S rRNA was used for molecular characterization of bacterial strain and the best nanocellulose producer was identified as Novacetimonas hansenii BMK-3_NC240423 (isolated from rotten banana). FTIR and FE-SEM studies of nanocellulose pellicle produced on HS medium and gram flour-table sugar medium demonstrated equivalent structural, morphological, and chemical properties. The cost of newly designed medium (0.01967 $/L) is nearly 90 times lower than the Hestrin-Schramm medium (1.748 $/L), which makes the screening of nanocellulose producers very cost-effective. A strategy of using gram flour extract-table sugar medium for the screening of nanocellulose-producing micro-organisms is a novel approach, which will drastically reduce the screening associated cost of cellulose-producing micro-organisms and also motivate the researchers/industries for comprehensive screening programme for getting high cellulose-producing microbes.

12.
Sensors (Basel) ; 24(7)2024 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-38610546

RESUMEN

The study of plant electrophysiology offers promising techniques to track plant health and stress in vivo for both agricultural and environmental monitoring applications. Use of superficial electrodes on the plant body to record surface potentials may provide new phenotyping insights. Bacterial nanocellulose (BNC) is a flexible, optically translucent, and water-vapor-permeable material with low manufacturing costs, making it an ideal substrate for non-invasive and non-destructive plant electrodes. This work presents BNC electrodes with screen-printed carbon (graphite) ink-based conductive traces and pads. It investigates the potential of these electrodes for plant surface electrophysiology measurements in comparison to commercially available standard wet gel and needle electrodes. The electrochemically active surface area and impedance of the BNC electrodes varied based on the annealing temperature and time over the ranges of 50 °C to 90 °C and 5 to 60 min, respectively. The water vapor transfer rate and optical transmittance of the BNC substrate were measured to estimate the level of occlusion caused by these surface electrodes on the plant tissue. The total reduction in chlorophyll content under the electrodes was measured after the electrodes were placed on maize leaves for up to 300 h, showing that the BNC caused only a 16% reduction. Maize leaf transpiration was reduced by only 20% under the BNC electrodes after 72 h compared to a 60% reduction under wet gel electrodes in 48 h. On three different model plants, BNC-carbon ink surface electrodes and standard invasive needle electrodes were shown to have a comparable signal quality, with a correlation coefficient of >0.9, when measuring surface biopotentials induced by acute environmental stressors. These are strong indications of the superior performance of the BNC substrate with screen-printed graphite ink as an electrode material for plant surface biopotential recordings.


Asunto(s)
Grafito , Agricultura , Transporte Biológico , Carbono , Clorofila , Vapor
13.
Nano Lett ; 23(6): 2100-2106, 2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36853199

RESUMEN

Printing thin-film transistors (TFTs) using nanomaterials is a promising approach for future electronics. Yet, most inks rely on environmentally harmful solvents for solubilizing and postprint processing the nanomaterials. In this work, we demonstrate water-only TFTs printed from all-carbon inks of semiconducting carbon nanotubes (CNTs), conducting graphene, and insulating crystalline nanocellulose (CNC). While suspending these nanomaterials into aqueous inks is readily achieved, printing the inks into thin films of sufficient surface coverage and in multilayer stacks to form TFTs has proven elusive without high temperatures, hazardous chemicals, and/or lengthy postprocessing. Using aerosol jet printing, our approach involves a maximum temperature of 70 °C and no hazardous chemicals─all inks are aqueous and only water is used for processing. An intermittent rinsing technique was utilized to address the surface adhesion challenges that limit film density of printed aqueous CNTs. These findings provide promising steps toward an environmentally friendly realization of thin-film electronics.

14.
Nano Lett ; 23(3): 880-886, 2023 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-36521008

RESUMEN

Clarifying the primary structure of nanomaterials is invaluable to understand how the nanostructures lead to macroscopic material functions. Nanocellulose is attracting attention as a sustainable building block in materials science. The surface of nanocellulose is often chemically modified by polymer grafting to tune the material properties, such as the viscoelastic properties in rheology modifiers and the reinforcement effect in composites. However, the structure, such as molecular conformation of the grafted polymer and the twist of the core nanocellulose, is not well understood. Here, we investigated the structure of polymer-grafted nanocellulose in the colloidal dispersion system by combining small-angle X-ray scattering measurement and all-atom molecular dynamics simulation. We demonstrated formation of the polymer brush layer on the nanocellulose surface in solvents, which explains the excellent colloidal stability. We also found that twisting of the nanocellulose in the core is suppressed by the existence of the polymer brush layer.

15.
J Environ Manage ; 352: 119928, 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38219662

RESUMEN

This review investigates the potential of nanocellulose in agriculture, encompassing its structure, synthesis, modification, and applications. Our investigation of the characteristics of nanocellulose includes a comprehensive classification of its structure. Various mechanical, chemical and enzymatic synthesis techniques are evaluated, each offering distinct possibilities. The central role of surface functionalization is thoroughly examined. In particular, we are evaluating the conventional production of nanocellulose, thus contributing to the novelty. This review is a pioneering effort to comprehensively explore the use of nanocellulose in slow and controlled release fertilizers, revolutionizing nutrient management and improving crop productivity with reduced environmental impact. Additionally, our work uniquely integrates diverse applications of nanocellulose in agriculture, ranging from slow-release fertilizers, superabsorbent cellulose hydrogels for drought stress mitigation, and long-lasting crop protection via nanocellulose-based seed coatings. The study ends by identifying challenges and unexplored opportunities in the use of nanocellulose in agriculture. This review makes an innovative contribution by being the first comprehensive study to examine the multiple applications of nanocellulose in agriculture, including slow-release and controlled-release fertilizers.


Asunto(s)
Protección de Cultivos , Fertilizantes , Preparaciones de Acción Retardada/química , Agricultura/métodos , Hidrogeles/química
16.
J Environ Manage ; 363: 121254, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38850909

RESUMEN

Despite being composed of recyclable materials, the main technological challenge of multilayer carton packs involves the efficient decompatibilization of the cellulosic, polymeric, and metallic phases. Here, a simple two-step mechanochemical process is described that uses only aqueous media and mechanical force to promote phase separation in order to fully recycle multi-layer carton packaging. The first step produces value-added micro- and nanocellulose, while in the second step, aluminum is extracted, forming precipitated aluminum and aluminum oxyhydroxides. Solid polyethylene (PE) remains with a degree of purity defined by the process efficiency. The results show that cellulose is efficiently extracted and converted into micro- and nanocellulose after 15 min of milling. In the second stage, approximately 90% of the aluminum is extracted from the PE after 15 min of milling. Due to the separation and drying medium conditions, the finely divided particles of extracted aluminum also have oxyhydroxides in their composition. It is believed that a passivation layer forms on the metallic aluminum particle. The techno-economic analysis revealed a positive net present value (NPV) of $17.5 million, with a minimum selling price of 1.62 USD/kg of cellulose. The environmental analysis concluded that most of the environmental impact of the process is associated with the entry of carton packages into the system, incorporating a small environmental load related to the industrial process. The results indicate a promising option toward a circular economy and carbon neutrality.


Asunto(s)
Celulosa , Reciclaje , Celulosa/química , Aluminio/química , Polietileno/química
17.
Small ; 19(44): e2303044, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37403301

RESUMEN

Lightweight porous hydrogels provide a worldwide scope for functional soft mateirals. However, most porous hydrogels have weak mechanical strength, high density (>1 g cm-3 ), and high heat absorption due to weak interfacial interactions and high solvent fill rates, which severely limit their application in wearable soft-electronic devices. Herein, an effective hybrid hydrogel-aerogel strategy to assemble ultralight, heat-insulated, and tough polyvinyl alcohol (PVA)/SiO2 @cellulose nanoclaws (CNCWs) hydrogels (PSCG) via strong interfacial interactions with hydrogen bonding and hydrophobic interaction is demonstrated. The resultant PSCG has an interesting hierarchical porous structure from bubble template (≈100 µm), PVA hydrogels networks introduced by ice crystals (≈10 µm), and hybrid SiO2 aerogels (<50 nm), respectively. PSCG shows unprecedented low density (0.27 g cm-3 ), high tensile strength (1.6 MPa) & compressive strength (1.5 MPa), excellent heat-insulated ability, and strain-sensitive conductivity. This lightweight porous and tough hydrogel with an ingenious design provides a new way for wearable soft-electronic devices.

18.
Small ; 19(30): e2302276, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37183294

RESUMEN

Nanocellulose is attracting attention in the field of materials science as a sustainable building block. Nanocellulose-based materials, such as films, membranes, and foams, are fabricated by drying colloidal dispersions. However, little is known about how the structure of a single nanocellulose changes during the complex drying process. Here, all-atom molecular dynamics simulations and atomic force microscopy is used to investigate the structural dynamics of single nanocellulose during drying. It is found that the twist morphology of the nanocellulose became localized along the fibril axis during the final stage of the drying process. Moreover, it is shown that conformational changes at C6 hydroxymethyl groups and glycoside bond is accompanied by the twist localization, indicating that the increase in the crystallinity occurred in the process. It is expected that the results will provide molecular insights into nanocellulose structures in material processing, which is helpful for the design of materials with advanced functionalities.

19.
Small ; 19(47): e2303615, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37501326

RESUMEN

Current research on hemostatic materials have focused on the inhibition of visible hemorrhage, however, invisible hemorrhage is the unavoidable internal bleeding that occurs after trauma or surgery, leading directly to a dramatic drop in hemoglobin and then to anemia and even death. In this study, bacterial nanocellulose (BNC) was synthesized and oxidized from the primary alcohols to carboxyl groups, and then grafted with tranexamic acid through amide bonds to construct degradable nanoscale short fibers (OBNC-TXA), which rapidly activated the coagulation response. The hemostatic material is made up of nanoscale short fibers that can be constructed into different forms such as emulsions, gels, powders, and sponges to meet different clinical applications. In the hemostatic experiments in vitro, the composites had significantly superior pro-coagulant properties due to the rapid aggregation of blood cells. In the coagulation experiments with rat tail amputation and liver trauma hemorrhage models, the group treated with OBNC-TXA1 sponge showed low hemorrhage and inhibited invisible hemorrhage in rectus abdominis muscle defect hemorrhage models, with a rapid recovery of hemoglobin values from 128±5.5 to 165±2.6 g L-1 within 4 days. In conclusion, the degradable short fibers constructed from bacterial nano-cellulose achieved inhibition of invisible hemorrhage in vivo.


Asunto(s)
Hemostáticos , Hepatopatías , Ácido Tranexámico , Ratas , Animales , Ácido Tranexámico/farmacología , Ácido Tranexámico/uso terapéutico , Hemorragia/tratamiento farmacológico , Hemostáticos/farmacología , Hemostáticos/uso terapéutico , Coagulación Sanguínea , Hemoglobinas/farmacología , Hemoglobinas/uso terapéutico
20.
Small ; : e2307810, 2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-38050940

RESUMEN

The technical synergy between flexible sensing paper and triboelectric nanogenerator (TENG) in the next stage of artificial intelligence Internet of Things engineering makes the development of intelligent sensing paper with triboelectric function very attractive. Therefore, it is extremely urgent to explore functional papers that are more suitable for triboelectric sensing. Here, a cellulose nanocrystals (CNCs) reinforced PVDF hybrid paper (CPHP) is developed by electrospinning technology. Benefitting from the unique effects of CNCs, CPHP forms a solid cross-linked network among fibers and obtains a high-strength (25 MPa) paper-like state and high surface roughness. Meanwhile, CNCs also improve the triboelectrification effect of CPHP by assisting the PVDF matrix to form more electroactive phases (96% share) and a higher relative permittivity (17.9). The CPHP-based TENG with single electrode configuration demonstrates good output performance (open-circuit voltage of 116 V, short-circuit current of 2.2 µA and power density of 91 mW m-2 ) and ultrahigh pressure-sensitivity response (3.95 mV Pa-1 ), which endows CPHP with reliable power supply and sensing capability. More importantly, the CPHP-based flexible self-powered tactile sensor with TENG array exhibits multifunctional applications in imitation Morse code compilation, tactile track recognition, and game character control, showing great prospects in the intelligent inductive device and human-machine interaction.

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