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1.
Fungal Biol ; 126(5): 356-365, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35501031

RESUMO

Successful application of microbial biofertilizers, such as phosphorus (P) solubilizing fungi to agroecosystems, is constrained from the lack of knowledge about their ecology; for example in terms of how they respond to an external input of carbon (C) to get established in the soil. In two soil incubation experiments we examined the performance of the P solubilizing fungus Penicillium aculeatum in non-sterile and semi-sterile (γ-irradiated) soil with different C and P sources. Results from the first experiment with C sources showed that starch and cellulose generally improved P solubilization by P. aculeatum measured as water extractable P (Pwep), though only significantly in non-sterile soil. This coincided with an increased population density of P. aculeatum measured with a hygromycin B resistant strain of this fungus. Soil respiration used to measure soil microbial activity was overall much higher in treatments with C compounds than without C in both non-sterile and semi-sterile soil. However, soil respiration was highest with cellulose in semi-sterile soil, especially in combination with P. aculeatum. Hence, for the second experiment with P sources (tricalcium phosphate (TCP) and sewage sludge ash) cellulose was used as a C source for P. aculeatum growth in all treatments. Main results showed that P. aculeatum in combination with cellulose soil amendment increased soil Pwep independent of soil sterilization and P source treatments. Soil resin P (Pres) and microbial P (Pmic), which represents stocks of potentially plant available P, were also affected from P. aculeatum inoculation. Increased soil Pres from TCP and sewage sludge ash was observed with P. aculeatum independent of soil type. On the other hand soil Pmic was higher after P. aculeatum inoculation only in semi-sterile soil. Population density of P. aculeatum measured with qPCR was maintained or increased in non-sterile and semi-sterile soil, respectively, compared to the original inoculum load of P. aculeatum. In conclusion, our results underline the importance of C source addition for P. aculeatum if used as a biofertilizer. For this, cellulose seems to be a promising option promoting P. aculeatum growth and P solubilization also in non-sterilized soil.


Assuntos
Solo , Talaromyces , Celulose , Esgotos , Microbiologia do Solo , Esterilização
2.
Mikrochim Acta ; 189(5): 206, 2022 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-35501613

RESUMO

Concerns for agri-food safety and environmental management require development of simple to use and cost- and time-effective multiplex sensors for point-of-need (PON) chemical analytics by public end-user. Simultaneous detection of nitrates, phosphates, and pH is of importance in soil and water analysis, agriculture, and food quality assessment. This article demonstrates a suite of stainless steel microneedle electrochemical sensors for multiplexed measurement of pH, nitrate, and phosphate using faradaic capacitance derived from cyclic voltammetry as the mode of detection. The multi-target microneedle sensors were fabricated by layer-by-layer (LbL) assembly in a stainless steel hypodermic microneedle substrate. For nitrate sensing, the stainless steel was coated with carbon nanotube/cellulose nanocrystal (CNT)/CNC) decorated with silver nanoparticles (Ag). For pH measurement, the polyaniline (pANI) was coated onto the CNT/CNC@Ag film, while for phosphate detection, the CNT/CNC/Ag @pANI microneedle was further decorated with ammonium molybdenum tetrahydrate (AMT). The microelectrode platforms were characterized by FTIR, Raman, and microscopic techniques. The nitrate- and phosphate-based microneedle electrochemical sensors had excellent selectivity and sensitivity, with a determined limit of detection (LOD) of 0.008 mM and 0.007 mM, respectively. The pH microneedle sensor was responsive to pH in the linear range of 3-10. The three microneedle sensors yielded repeatable results, with a precision ranging from 4.0 to 7.5% RSD over the concentration ranges tested. The inexpensive (~ 1 $ CAD) microneedle sensors were successfully verified for use in quantification of nitrate, pH, and phosphate in brewed black coffee as a real sample. As such, the microneedle sensors are economical devices and show great promise as robust platforms for PON precision chemical analytics.


Assuntos
Nanopartículas Metálicas , Nitratos , Celulose , Técnicas Eletroquímicas/métodos , Concentração de Íons de Hidrogênio , Fosfatos , Prata/química , Aço Inoxidável
3.
Methods Mol Biol ; 2469: 103-118, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35508833

RESUMO

Sugarcane bagasse has received attention as a raw material for the production of second-generation ethanol (E2G). However, its use is limited because of the cell wall recalcitrance, mostly conferred by lignin. Recently our knowledge of the genes coding for the enzymes of the lignin biosynthesis pathway has increased; however, still little is known about the transcription factors controlling the expression of these genes in sugarcane. Here we describe protocols to optimize the isolation of the promoters of the lignin biosynthetic genes ShCAD8, ShCOMT and ShF5H and the transcription factors (TFs) ShMYB85 and ShMYB58/63 in Saccharum species. To confirm whether these TFs are able to activate the target promoters, a transactivation assay in BY2 protoplasts of Nicotiana tabacum is also detailed.


Assuntos
Saccharum , Celulose/metabolismo , Regulação da Expressão Gênica de Plantas , Lignina/metabolismo , Saccharum/genética , Saccharum/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
4.
BMC Microbiol ; 22(1): 104, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35421928

RESUMO

BACKGROUND: Bacterial floc formation plays a central role in the activated sludge (AS) process. The formation of AS flocs has long been known to require exopolysaccharide biosynthesis. We had demonstrated that both expolysaccharides and PEP-CTERM (a short C-terminal domain includes a near-invariant motif Pro-Glu-Pro (PEP)) proteins were required for floc-forming in Zoogloea resiniphila MMB, a dominant AS bacterium. However, the PEP-CTERM proteins are not encoded in the genome of AS bacterium Shinella zoogloeoides ATCC 19623 (formerly known as Zoogloea ramigera I-16-M) and other sequenced AS bacteria strains. The mechanism underlying floc formation of Shinella and related AS bacteria remained largely unclear. RESULTS: In this study, we have sequenced and annotated the complete genome of S. zoogloeoides ATCC 19623 (aka I-16-M), previously isolated in USA and treated as the neotype for the AS floc-forming bacterium Zoogloea ramigera I-16-M, and another AS strain XJ20 isolated in China. Mariner transposon mutagenesis had been conducted to isolate floc-forming-deficient mutants in the strain ATCC 19623 as previously performed by using Tn5 transposon three decades ago. The transposon insertional sites of multiple mutants were mapped to the gene cluster for bacterial cellulose synthesis (bcs) and secretion, and the role played by these genes in floc-formation had been further confirmed by genetic complementation. Interestingly, the restriction map of this bcs locus-flanking region was highly similar to that of the previously identified DNA fragment required for floc-formation in 1980s. Cellulase treatment abolished the floc-forming phenotype of S. zoogloeoides ATCC 19623 but not that of Z. resiniphila MMB strain. The FTIR spectral analyses revealed that the samples extracted from S. zoogloeoides ATCC 19623 were cellulose polymer. CONCLUSION: Our results indicated that we have largely reproduced and completed the unfinished pioneering work on AS floc-formation mechanism, demonstrating that the floc-formation and flocculating capability of Shinella were mediated by extracellular cellulose polymers.


Assuntos
Rhizobiaceae , Esgotos , Celulose , Esgotos/microbiologia , Zoogloea
5.
Int J Mol Sci ; 23(8)2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35456918

RESUMO

Despite the recent advancements in treating bacterial infections, antibiotic resistance (AR) is still an emerging issue. However, polymeric nanocarriers have offered unconventional solutions owing to their capability of exposing more functional groups, high encapsulation efficiency (EE) and having sustained delivery. Natural polymeric nanomaterials (NMs) are contemplated one of the most powerful strategies in drug delivery (DD) in terms of their safety, biodegradability with almost no side effects. Every nanostructure is tailored to enhance the system functionality. For example, cost-effective copper NPs could be generated in situ in cellulose sheets, demonstrating powerful antibacterial prospects for food safety sector. Dendrimers also have the capacity for peptide encapsulation, protecting them from proteolytic digestion for prolonged half life span. On the other hand, the demerits of naturally sourced polymers still stand against their capacities in DD. Hence, Post-synthetic modification of natural polymers could play a provital role in yielding new hybrids while retaining their biodegradability, which could be suitable for building novel super structures for DD platforms. This is the first review presenting the contribution of natural polymers in the fabrication of eight polymeric NMs including particulate nanodelivery and nanofabrics with antibacterial and antibiofilm prospects, referring to modified polymer derivatives to explore their full potential for obtaining sustainable DD products.


Assuntos
Infecções Bacterianas , Nanoestruturas , Antibacterianos/química , Antibacterianos/farmacologia , Celulose , Humanos , Nanoestruturas/química , Polímeros/química
6.
Int J Mol Sci ; 23(8)2022 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-35456954

RESUMO

Xylanase releases xylo-oligosaccharides from dietary xylan, which stimulate the growth of the gut bacteria lactobacilli. Many lactobacilli adhere to dietary fibers, which may facilitate the assimilation of xylo-oligosaccharides and help them gain competence in the gut, but the underlying mechanisms remain elusive. Herein we report, from the highly abundant transcripts of Lactobacillus brevis cultured in wheat arabinoxylan supplemented with a xylanase, the identification of genes encoding four putative cell-surface WxL proteins (Lb630, Lb631, Lb632, and Lb635) and one S-layer protein (Lb1325) with either cellulose- or xylan-binding ability. The repetitively occurring WxL proteins were encoded by a gene cluster, among which Lb630 was chosen for further mutational studies. The analysis revealed three aromatic residues (F30, W61, and W156) that might be involved in the interaction of the protein with cellulose. A homology search in the genome of Enterococcus faecium identified three WxL proteins with conserved counterparts of these three aromatic residues, and they were also found to be able to bind cellulose and xylan. The findings suggested a role of the cell-surface WxL and S-layer proteins in assisting the cellular adhesion of L. brevis to plant cell wall polysaccharides.


Assuntos
Lactobacillus brevis , Xilanos , Celulose/metabolismo , Lactobacillus brevis/genética , Lactobacillus brevis/metabolismo , Glicoproteínas de Membrana , Proteínas de Membrana/metabolismo , Oligossacarídeos , Xilanos/metabolismo
7.
Sci Rep ; 12(1): 6748, 2022 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-35468931

RESUMO

In the present study, we elucidated the effect of grain-based (GB) diet containing both soluble and insoluble fibers and purified ingredients-based (PIB) diet containing only insoluble fiber, namely cellulose on mice gut microbiome using whole shotgun based metagenomic sequencing. Although the fiber content in both diet types is the same (5%) the presence of soluble fiber only in the GB diet differentiates it from the PIB diet. The taxonomic analysis of sequenced reads reveals a significantly higher enrichment of probiotic Lactobacilli in the GB group as compared to the PIB group. Further, the enhancement of energy expensive cellular processes namely, cell cycle control, cell division, chromosome partitioning, and transcription is observed in the GB group which could be due to the metabolization of the soluble fiber for faster energy production. In contrast, a higher abundance of cellulolytic bacterial community namely, the members of family Lachnospiraceae and Ruminococcaceae and the metabolism functions are found in the PIB group. The PIB group shows a significant increase in host-derived oligosaccharide metabolism functions indicating that they might first target the host-derived oligosaccharides and self-stored glycogen in addition to utilising the available cellulose. In addition to the beneficial microbial community variations, both the groups also exhibited an increased abundance of opportunistic pathobionts which could be due to an overall low amount of fiber in the diet. Furthermore, backtracing analysis identified probiotic members of Lactobacillus, viz., L. crispatus ST1, L. fermentum CECT 5716, L. gasseri ATCC 33323, L. johnsonii NCC 533 and L. reuteri 100-23 in the GB group, while Bilophila wadsworthia 3_1_6, Desulfovibrio piger ATCC 29098, Clostridium symbiosum WAL-14163, and Ruminococcaceae bacterium D16 in the PIB group. These data suggest that Lactobacilli, a probiotic community of microorganisms, are the predominant functional contributors in the gut of GB diet-fed mice, whereas pathobionts too coexisted with commensals in the gut microbiome of the PIB group. Thus at 5% fiber, GB modifies the gut microbial ecology more effectively than PIB and the inclusion of soluble fiber in the GB diet may be one of the primary factors responsible for this impact.


Assuntos
Metagenoma , Prebióticos , Animais , Celulose/farmacologia , Dieta , Fibras na Dieta/farmacologia , Grão Comestível , Lactobacillus/genética , Metagenômica , Camundongos
8.
Sci Rep ; 12(1): 6682, 2022 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-35461316

RESUMO

This study aims at evaluating the reinforcement of cellulose nanocrystals (CNCs) in epoxidized natural rubber (ENR). Both CNCs and maleic anhydride-modified CNCs (M-CNCs) were prepared from Napier grass stems and characterized by various techniques (e.g., TEM, FTIR, TGA, etc.). They were incorporated into ENR latex at various loadings prior to casting, and then curing by ultraviolet (UV) irradiation. Mechanical properties of the ENR vulcanizates were finally investigated. Results revealed that the prepared CNCs had an average diameter and length of 5 nm and 428 nm, respectively. After modification, M-CNCs contained double bonds in maleate units, which could react with ENR to form covalent bonds under UV irradiation through a proposed mechanism. Regardless of the filler type, mechanical properties including hardness, modulus, and tensile strength, increased considerably with increasing filler loading. At the same filler loading, M-CNCs exhibited greater reinforcement than CNCs due to the enhanced rubber-filler interaction.


Assuntos
Nanopartículas , Borracha , Celulose/química , Nanopartículas/química , Borracha/química , Resistência à Tração
9.
Carbohydr Polym ; 289: 119406, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483830

RESUMO

Mimicking the cellular machineries-based ion transport phenomenon for multipurpose applications of the nanofluidic devices has inspired scientific community. Owing to this phenomenon, various artificial nanofluidic systems are highly desirable for energy-environment associated fields including energy storage and conversion, biosensing, and desalination of seawater. Nevertheless, high cost and low efficiency hamper the development of nanofluidic devices in the respective fields. Pertinently, cellulose-based nanofluidic devices rectified the ionic transport property and offer an efficient and sustainable platform for harvesting osmotic energy. Recently, the design strategies of cellulose-based nanofluidic materials provided a more targeted material design for specific applications. Herein, we briefly introduce the structural aspects of cellulose, review the structural features and ion transport properties of cellulose-based nanofluidic materials, and highlight their applications as osmotic energy generators, sensors, transistors, flexible electronic skins, and bio-detection devices. In summary, the challenges and future perspectives of cellulose-based nanofluidic materials are described.


Assuntos
Celulose , Nanotecnologia , Transporte de Íons , Osmose
10.
Carbohydr Polym ; 289: 119408, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483831

RESUMO

The study evaluated the effect of cryogrinding, a relatively new, cost-effective, and sustainable mechanical treatment method, on physicochemical properties of two different micronaire (3.6- and 5.3-) cotton fiber cellulose. Native (type I), mercerized (type II), and acidulated cellulose were subjected to cryogrinding for 48 and 96 min, and their physicochemical properties were investigated. The results demonstrated that cryogrinding resulted in partial amorphization of native and mercerized celluloses, particle size decrease, and a slight reduction of T50%. Importantly, degree of polymerization (DP) of native cellulose reduced significantly: more than two-fold after 12 cycles and more than three-fold after 24 cycles of cryogrinding. No difference in properties was found between 3.6- and 5.3-micronaire cellulose. Advantageous impacts of cryogrinding found in this work will help signify the potential of this technique in cellulose processing and enable the identification of areas for future development.


Assuntos
Celulose , Fibra de Algodão , Celulose/química , Polimerização
11.
Carbohydr Polym ; 289: 119419, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483837

RESUMO

There is a growing interest in the synthesis of electrically conductive cellulose nanocrystal (CNC) for advanced applications, such as supercapacitor, batteries, sensor, and printed electronics. CNC is recognized as an attractive template for the fabrication of functional nanomaterials. Since CNC possesses many attractive properties, it is a sustainable template to prepare conductive nanomaterials, by either coating it with a conductive material or transforming it into carbon nanorods. This review summarizes the utilization of a sustainable and low-cost CNC to produce conductive nanocomposites via an environmentally friendly process. Electroconductive CNCs with enhanced electrical properties, lower electrical percolation threshold, and better mechanical properties can be produced and are attractive systems for many new applications.


Assuntos
Nanocompostos , Nanopartículas , Metabolismo dos Carboidratos , Celulose/química , Condutividade Elétrica , Nanocompostos/química , Nanopartículas/química
12.
Carbohydr Polym ; 289: 119425, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483839

RESUMO

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


Assuntos
Celulose , Nanofibras , Carbonato de Cálcio/química , Celulose/química , Íons , Minerais , Nanofibras/química
13.
Carbohydr Polym ; 289: 119430, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483843

RESUMO

In this study, high-substituted hydroxypropyl cellulose (HHPC) and low-substituted hydroxypropyl cellulose (LHPC) were orally administered (150 or 300 mg/kg) to investigate the inflammation inhibitory effects on DSS-induced colitis mice. In addition, the anti-inflammatory potential of HHPC in-vitro (RAW 264.7 cells) was evaluated. The result showed that HHPC could inhibit the excessive secretion of TNF-α, IL-6, and NO in RAW 264.7 cells induced by lipopolysaccharide. Oral administration of HHPC and LHPC could dose-dependently mitigate the pathological damage of colon tissue, suppressed spleen edema, preserved thymus index, reduced the serum level of inflammatory mediators (TNF-α, IL-6, IL-1ß, and MPO), increased the secretion of sIgA in the colon, and restored the balance of the intestinal flora such as Rikenellaceae_RC9_gut_group, Lachnospiraceae_UCG-006, and Blautia. Overall, this study elucidated the therapeutic potential of LHPC and HHPC as a prebiotic to treat acute ulcerative colitis.


Assuntos
Colite , Fator de Necrose Tumoral alfa , Animais , Celulose/análogos & derivados , Colite/induzido quimicamente , Colite/tratamento farmacológico , Colite/patologia , Sulfato de Dextrana/toxicidade , Interleucina-6 , Camundongos , Fator de Necrose Tumoral alfa/efeitos adversos
14.
Carbohydr Polym ; 289: 119432, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483845

RESUMO

When compared with traditional petroleum-based materials, bio-based materials show greater application potential in the field of biomedicine owing to the good biocompatibility, in specifical, the application of natural macromolecular polymers in chemotherapeutics has become a hot topic in anticancer treatment. In this study, cellulose nanocrystals (CNCs) were selected as carriers, and Au nanoparticles (NPs) were directly conjugated on their surface, with the highly reactive Cu2+ ions serving as an ion-ligand bridge, to construct a multifunctional nanocatalyst. These findings suggest that the nanosystem delivers a large amount of highly reactive Cu2+ ions (3.75 wt%) and DOX (7.71 wt%) by the surface loading of cellulose nanocrystals, which greatly improves ROS yield and promotes the application of the Fenton reaction system in cancer therapy.


Assuntos
Cobre , Nanopartículas Metálicas , Celulose , Cobre/química , Ouro/química , Nanopartículas Metálicas/química , Polímeros , Espécies Reativas de Oxigênio
15.
Carbohydr Polym ; 289: 119434, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483847

RESUMO

Drying-induced hornification is an inevitable phenomenon of cellulosic fibers, which is used to describe internal aggregation structure changes of cellulosic fibers upon drying or water removal. To investigate the hornification process, never-dried cellulosic fibers with different components were thermally dried to different moisture contents. The results indicated that the hornification process could be divided into four stages, including the first crystallization period (>70% moisture), the cocrystallization period (70-31% moisture), the hemicellulose control period (31-11% moisture), and the second crystallization period (11-0% moisture). The decrease of water retention value (WRV) occurred in the cocrystallization period and the second crystallization period, which meant hornification happened in these two periods. Besides, hemicellulose and lignin inhibited hornification by reducing cellulose cocrystallization. The work elucidates the hornification process and mechanism of cellulosic fibers,which will be helpful to control the properties of cellulosic materials for extended utilization.


Assuntos
Celulose , Dessecação , Celulose/química , Cristalização , Lignina , Água/química
16.
Carbohydr Polym ; 289: 119442, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483855

RESUMO

Carboxylated cellulose nanocrystals prepared by TEMPO-mediated oxidation exhibit a distinct ability to form nematic order, however, their ability to form chiral nematic films remains relatively unexplored. In this study, bleached cotton pulp hydrolyzed with hydrochloric acid and oxidized by TEMPO-mediated oxidation produce carboxylated cellulose nanocrystals with different aspect ratios 33.1, 32.8, 30.9, 29.0 and 28.9, and surface charge densities 0.16, 0.56, 1.00, 1.25, and 1.42 e·nm-2. By tuning the aspect ratio and surface charge density, the optimal carboxylated cellulose nanocrystals producing left-handed chiral nematic films by evaporation-induced self-assembly are obtained. The left-handed chiral nematic films enable selective reflection of left-handed circularly polarized light with the peak wavelength tunable from the visible to the near-infrared regime by modifying the characteristics of nanorods and suspensions. Such carboxylated cellulose nanocrystal films transform spontaneous luminescence to right-handed circularly polarized luminescence with the peak luminescence dissymmetry factor of -0.51.


Assuntos
Celulose , Nanopartículas , Celulose/química , Nanopartículas/química , Oxirredução , Suspensões
17.
Carbohydr Polym ; 289: 119459, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483861

RESUMO

The aim of this research was to investigate for the first time the possible application range of sustainable cellulose-filled polymer-based materials dedicated for common use in healthcare sector. These products are exposed to contact with solutions of different acidity, microorganisms and are being constantly UV sterilized. Therefore, the impact of plant filler on the microbial growth, UV-aging and pH-resistance of cellulose-filled ethylene-norbornene copolymer (EN) was investigated, as the polymer matrix employed is widely used in healthcare applications. Moreover, two different coupling agents, vinyltrimethoxysilane (VTMS) and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS), were used to promote the adhesion between the polymer matrix and cellulose (hydrophobization of fibres evidenced with increased water contact angle from 15 to 130°). Additionally, UV-aging revealed that the silane-originated functional groups might have possibly acted as free radical scavengers, hence, prolonging composites' shelf-life. Furthermore, incorporation of investigated amount of cellulose did not result in the decreased pH-resistance or improved growth of Escherichia coli.


Assuntos
Antibacterianos , Celulose , Farmacorresistência Bacteriana , Etilenos , Norbornanos , Polímeros
18.
Carbohydr Polym ; 289: 119461, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483862

RESUMO

Chiral nematic papers (CNPs) with mesopores structure based on cellulose nanocrystals (CNCs) were fabricated successfully via a swelling and freeze-drying method. The order of the original chiral nematic cellulose nanocrystals film was preserved in CNPs, which was proved by scanning electron microscopy (SEM), polarized optical microscopy (POM) measurements and circular dichroism (CD) spectra. The CNPs exhibited excellent optical responsive properties to different solvents. Inspired by this feature, a colorable ink containing amounts of gel particles was prepared by pulverizing CNPs/water mixture into a suspension. Patterns written in suspension ink with various colors can be formed when soaked with different solvents. Moreover, CNPs displayed an irreversible color response to compression. Additionally, the hydrophilicity of CNPs was tuned by polyethyleneimine. Modified CNPs exhibited different colors under the identical solvent environment when compared to the original one. Aqueous PEI can be used as an ink to depict responsive photonic patterns on CNPs.


Assuntos
Celulose , Nanopartículas , Celulose/química , Excipientes , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Solventes
19.
Int J Biol Macromol ; 207: 917-926, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35364193

RESUMO

Lignin-containing bamboo cellulose, fractionated from a pilot-scale microwave liquefaction of bamboo was dissolved in tetrabutylammonium acetate/dimethyl sulfoxide (TBAA/DMSO) for the fabrication of highly flexible, transparent and UV-blocking films. Tea polyphenol (TP) or citric acid (CA) was added during the dissolving process in order to modify the film's properties. The results showed that the addition of TP obviously improved the elongation at break (triple that of the control) and UV-blocking ability of the films. Both the addition of TP and CA could increase the water contact angle of the films. The films incorporated with TP and CA were much more thermal stable than previously reported similar films. The proposed film fabrication mechanism revealed that stable hydrogen bonds formed between the lignin-cellulose matrix and TP/CA, resulting in the enhancement on the properties of the films. This present study showed that lignin-containing cellulose with the incorporation of TP/CA had great potential in the preparation of films in place of plastic.


Assuntos
Celulose , Lignina , Celulose/química , Ácido Cítrico , Lignina/química , Polifenóis/química , Chá
20.
Int J Biol Macromol ; 207: 927-940, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35364194

RESUMO

Up to now, unbalanced mechanical properties and poor heat resistance have become two major problems of polylactic acid (PLA). In this study, the coupling between Cellulose nanocrystal (CNC) and strong shearing field formed a unique hierarchical structure. Compared with pure PLA, the tensile strength of DPIM PLA/CNC increased from 57.9 MPa to 79.6 MPa without sacrificing the toughness of PLA, and the vicat softening temperature of DPIM PLA/CNC increased from 60 °C to 155 °C. The microstructure of PLA/CNC composites was analyzed by SEM, SAXS and WAXD, and it was found that the coupling effect of CNC and strong shear flow field could significantly change the crystallization behavior of PLA. CNC could increase PLA shish length from 251 nm to 889 nm under the action of shear field. At the same time, due to this coupling effect, more PLA shish-kebab structures were induced at the interface. This special hierarchical structure composed of CNC and PLA Shish-Kebab is of great significance and can provide important guidance for achieving the balance of strength and toughness of polymer materials.


Assuntos
Celulose , Nanopartículas , Celulose/química , Nanopartículas/química , Poliésteres/química , Espalhamento a Baixo Ângulo , Difração de Raios X
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