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3D multifunctional scaffold has been designed based on Cs/SA/NS/NPHA. Nanoparticles hydroxyapatite (NPHA) was prepared via precipitation method of sodium dihydrogen phosphate in presence calcium chloride. Different ratios of Chitosan (CS)/Sodium Alginate (SA) were used to prepare Cs/SA scaffolds in presence of CaCl2 as a cross linker. NPHA was incorporated in CS/SA scaffold and neomycin sulfate (NS) was added as an antimicrobial agent. The structure and surface morphology of the scaffolds were investigated via infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermal gravimetric analysis (TGA) techniques. Additionally, Antimicrobial activity of the scaffold has evaluated against Gram- negative and Gram- positive bacteria. The result showed promising antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. Furthermore, cytotoxicity against MG63 osteosarcoma cell and fibroblast normal cell line has investigated. The result showed anti-proliferative against MG63. DFT calculations and molecular docking were used to study the reactivity of the compounds. The results exhibited that Cs/SA/NS/NPHA is potent expected to be used in bone tissue regeneration.
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Alginatos , Anti-Infecciosos , Proliferação de Células , Quitosana , Durapatita , Simulação de Acoplamento Molecular , Neomicina , Alicerces Teciduais , Quitosana/química , Quitosana/farmacologia , Durapatita/química , Alginatos/química , Alginatos/farmacologia , Neomicina/farmacologia , Neomicina/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Humanos , Proliferação de Células/efeitos dos fármacos , Alicerces Teciduais/química , Teoria da Densidade Funcional , Testes de Sensibilidade MicrobianaRESUMO
This study aims to explore the prevention of chitosan modified with a fused heterocyclic compound as a sustainable corrosion inhibitor for mild steel in 1 M HCl. Electrochemical instruments, including potentiodynamic polarization techniques, and electrochemical impedance spectroscopy (EIS), were employed to evaluate the corrosion protection performance. The outcomes showed that the chitosan modified with a fused heterocyclic compound has outstanding inhibition performance, with an inhibition effectiveness of 98.25 % at 100 ppm. The anti-corrosion features of modified chitosan were ascribed to the presence of hetero atoms in modified chitosan composite which leads to the creation of a protective layer, The modified chitosan composite behaved as mixed-typed inhibitors, as shown by the PDP results. The modified chitosan composite adsorbs on mild steel in the investigated corrosive media via chemisorption interactions, and its adsorption followed the Langmuir adsorption model. Furthermore, increasing the temperature from 303 to 333 K enhanced the corrosion rate, most likely due to the desorption of the inhibitor agent from the steel surface.
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Quitosana , Quitosana/química , Aço/química , Corrosão , Propriedades de Superfície , Ácido Clorídrico/químicaRESUMO
In this study, novel Cu-complexes of heterocyclic cellulose which were synthesized via the reaction of carboxymethyl cellulose (CMC) from bagasse pulp with NH2NH2 to give hydrazide cellulose which easily reacted with CS2 to form salt and then cyclized in the presence of HCl to afford cellulose oxadiazole, or with hydrazine hydrate to give cellulose triazole. Furthermore, the cellulose oxadiazole and triazole moieties acting as chelating agents with metal ion Cu (II), and all synthesized compounds were examined for their spectral analysis to show the adsorption of Cu (II) on the surface of cellulose through intramolecular hydrogen bonding. Results illustrated that cellulose oxadiazole and Cu- cellulose oxadiazole exhibited antimicrobial activities more than triazole and Cu- cellulose triazole. Furthermore, anticancer results showed that both cellulose oxadiazole and triazole exhibited activity higher than Cu-cellulose oxadiazole and Cu-cellulose triazole, where the cellulose triazole showed the highest activity (IC50â¯=â¯58.7⯵g/µL). Additionally, the docking simulation of the synthesized cellulose complexes with different proteins such as PDBID:3t88, PDBID:4ynt, PDBID:1tgh, PDBID:2wje, and PDBID:4hdq and shortage bond length to confirm the experimental results. Optimization of metal complexes utilized the DFT/B3LYP/LANL2DZ basis set to confirm the stability of these metals theoretically and their physical descriptors and FMO analysis.
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Anti-Infecciosos , Antineoplásicos , Celulose , Cobre , Simulação de Acoplamento Molecular , Celulose/química , Cobre/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Humanos , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/síntese química , Teoria da Densidade Funcional , Testes de Sensibilidade Microbiana , Compostos Heterocíclicos/química , Compostos Heterocíclicos/farmacologia , Linhagem Celular TumoralRESUMO
Chronic wounds (CWs) treatment still represents a demanding medical challenge. Several intrinsic physiological signals (i.e., pH) help to stimulate and support wound healing. CWs, in fact, are characterized by a predominantly alkaline pH of the exudate, which acidifies as the wound heals. Therefore, pH-responsive wound dressings hold great potential owing to their capability of tuning their functions according to the wound conditions. Herein, porous chitosan (CS)-based scaffolds loaded with cellulose nanocrystals (CNCs) and graphene oxide (GO) were successfully fabricated using a freeze-drying method. CNCs were extracted from bagasse pulps fibers through acid hydrolysis. GO was synthesised by Hummer's method. The scaffolds were then ionically cross-linked using the amino acid L-Arginine (Arg), as a bioactive agent, and tested as potential pH-responsive wound dressing. Notably, the effect of CNCs and GO singly and simultaneously loaded within the CS-Arg scaffolds was investigated. The modulation of CNCs and GO content within CS-Arg scaffolds facilitated the development of scaffolds with an optimal pH-dependent swelling ratio capability and extended degradation time. Furthermore, CS/CNC/GO-Arg scaffolds exhibited tuned biological features, in terms of antimicrobial activity, cellular proliferation/migration ability, and the expression of extracellular matrix specific markers (i.e., elastin and collagen I) related to wound healing in human dermal fibroblasts.
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In this study, the oxidation of microcrystalline cellulose using NaIO4 to yield the corresponding cellulose aldehyde utilized microwave irradiation as a green tool, the obtained cellulosic aldehyde was confirmed through spectral analysis and it has an active site to react with the synthesized uracil acetamide to afford the corresponding arylidene cellulosic MDAU(4), the latter compound which can easily due to presence of active CH=group behind a cyano group react with nitrogen nucleophile's and cyclized with hydrazine hydrate to give pyrazole cellulosic MDPA(5). The spectral analysis of the obtained cellulosic derivatives was confirmed with FT-IR, NMR, and SEM. Additionally, a neutral red uptake analysis has been used to investigate the cytotoxic activity of the cellulosic compounds MDAC(2), MDAU(4), and MDAP(5) against the cancer cells A549 and Caco2. After 48 h, Compound MDAU(4) had a stronger inhibitory effect on the growth of A549 and Caco2, compared to standard values. Then, using QRT-PCR, the appearance sites of the genes -Catenin, c-Myc, Cyclin D1, and MMP7 in A549 cells were examined. By reducing the expression levels of the Wnt signaling cascade genes -Catenin, c-Myc, Cyclin D1, and MMP7 when administered to A549 cells, compound MDAU(4) was shown in this investigation to be a viable candidate compared to lung cancer. Additionally, docking simulation was used to explore the uracil cellulosic heterocycles attached to different proteins, and computational investigations of these compounds looked at how well their physical characteristics matched the outcomes of their experiments.
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Ciclina D1 , Metaloproteinase 7 da Matriz , Humanos , Células CACO-2 , Espectroscopia de Infravermelho com Transformada de Fourier , Aldeídos , Cateninas , Biologia MolecularRESUMO
The reaction of cyanoethyl cellulose with para-bromo diazonium chloride resulted in the creation of a novel bromo-containing cellulosic (MCPT). The dispersion stability of MCPT has been improved by its dispersion into 1% waterborne polyurethane acrylate (WPUA). TEM, particle size, and zeta potential were used to track the dispersion stability of aqueous MCPT and MCPT in 1% WPUA and particle size. The prepared MCPT has been utilized as a unique green colorant (dye) for the printing of cotton, polyester, and cotton/polyester blend fabrics using a silkscreen printing technique through a single printing step and one color system. Color improvement has been achieved by printing different fabrics with a printing paste of MCPT dispersed in 1% WPUA. The MCPT and MCPT in 1% WPUA printed fabrics were evaluated for rubbing, light, washing, and perspiration fastness, UV blocking activity, and antibacterial activity. These findings were established through structural optimization at the DFT/B3LYP/6-31 (G) level and simulations involving several proteins.
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Synthesis of new compounds that have biological activity is an indispensible issue in order to deal with the drug resistant bacteria. This wok reports preparation of a novel composite based on substituted pyrido[2,1-b][1,3,4] oxadiazine-dialdehyde chitosan (PODACs) conjugate. Firstly, a novel approach of synthesizing of a new substituted pyrido[2,1-b][1,3,4]oxadiazine-7-carboxylic acid (PO) is reported through reacting(Z)-N'-(1-(3-aminophenyl)ethylidene)-2-cyanoacetohydrazide with (Z)-ethyl 2-cyano-3-(pyridin-3-yl)acrylate. Then Dialdehyde chitosan (DACs) has prepared via periodat oxidation of chitosan (Cs). The synthesized compounds have studied via various spectroscopic instruments to validate their chemical structure such as nuclear magnetic resonance 1 H NMR, 13 C NMR, fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The substituted pyrido [2,1-b][1,3,4]oxadiazine and the composite were evaluated for antimicrobial activity against pathogenic bacteria and unicellular fungi. The results revealed that, the composite exhibited promising antimicrobial activity against E. coli, S. aureus, B. subtilis and C. albicans where inhibition zones were 19, 18, 36 and 20 mm respectively. Furthermore, the substituted pyrido [2,1-b][1,3,4]oxadiazine and the composite were evaluated for cytotoxic activity against MCF-7 human breast cancer cell line as well as vero normal cell line. Results illustrated the prepared composite has anticancer activity against MCF7 where IC50 was 238 µg/ml.
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A novel adsorbent was prepared using a backbone comprising chemically hybridized dialdehyde cellulose (DAC) with chitosan via Schiff base reaction, followed by graft copolymerization of acrylic acid. Fourier transform infrared spectroscopy (FTIR) confirmed the hybridization while scanning electron microscopy (SEM) revealed intensive covering of chitosan onto the surface of DAC. At the same time, energy dispersive X-ray (EDX) proved the emergence of nitrogen derived from chitosan. The X-ray diffraction (XRD) indicated that the crystallinity of the backbone and graft copolymer structures was neither affected post the hybridization nor the grafting polymerization. The adsorbent showed high swelling capacity (872%) and highly efficient removal and selectivity of Ni2+ in the presence of other disturbing ions such as Pb2+ or Cu2+. The kinetic study found that the second-order kinetic model could better describe the adsorption process of (Cu2+, Ni2+) on the graft copolymer. In contrast, the first-order kinetic model prevails for the binary mixture (Pb2+, Ni2+). Moreover, the correlation coefficient values for the adsorption process of these binary elements using Langmuir and Freundlich isotherms confirmed that the developed grafted DAC/chitosan exhibits a good fit with both isotherm models, which indicates its broadened and complicated structure. Furthermore, the grafted DAC/chitosan exhibited high efficient regeneration and high adsorption capacity for Pb2+, Cu2+ and Ni2+.
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Graphene oxide (GO) and its reduced form (rGO) have recently attracted a fascinating interest due to their physico-chemical properties, which have opened up new and interesting opportunities in a wide range of biomedical applications, such as wound healing. It is worth noting that GO and rGO may offer a convenient access to its ready dispersion within various polymeric matrices (such as cellulose and its derivative forms), owing to their large surface area, based on a carbon skeleton with many functional groups (i.e., hydroxyl, carboxyl, epoxy bridge, and carbonyl moieties). This results in new synergic properties due to the presence of both components (GO or rGO and polymers), acting at different length-scales. Furthermore, they have shown efficient antimicrobial and angiogenic properties, mostly related to the intracellular formation of reactive oxygen species (ROS), which are advantageous in wound care management. For this reason, GO or rGO integration in cellulose-based matrixes have allowed for designing highly advanced multifunctional hybrid nanocomposites with tailored properties. The current review aims to discuss a potential relationship between structural and physico-chemical properties (i.e., size, edge density, surface chemistry, hydrophilicity) of the nanocomposites with antimicrobials and angiogenic mechanisms that synergically influence the wound healing phenomenon, by paying particular attention to recent findings of GO or rGO/cellulose nanocomposites. Accordingly, after providing a general overview of cellulose and its derivatives, the production methods used for GO and rGO synthesis, the mechanisms that guide antimicrobial and angiogenic processes of tissue repair, as well as the most recent and remarkable outcomes on GO/cellulose scaffolds in wound healing applications, will be presented.
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Biopolymers have significant pharmaceutical applications, and their blending has favorable characteristics for their pharmaceutical properties compared to the sole components. In this work, sodium alginate (SA) as a marine biopolymer was blended with poly(vinyl) alcohol (PVA) to form SA/PVA scaffolds through the freeze-thawing technique. Additionally, polyphenolic compounds in Moringa oleifera leaves were extracted by different solvents, and it was found that extracts with 80% methanol had the highest antioxidant activity. Different concentrations (0.0-2.5%) of this extract were successfully immobilized in SA/PVA scaffolds during preparation. The characterization of the scaffolds was carried out via FT-IR, XRD, TG, and SEM. The pure and Moringa oleifera extract immobilized SA/PVA scaffolds (MOE/SA/PVA) showed high biocompatibility with human fibroblasts. Further, they showed excellent in vitro and in vivo wound healing capacity, with the best effect noted for the scaffold with high extract content (2.5%).
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Reactivity of MCEC (3) with diazonium chloride, DMF-DMA and NH2NH2 to afford fused heterocyclic cellulosic derivative which confirmed through spectral analysis. Also, the cellulosic compounds were evaluated their growth inhibitory activity contra cancer cells A549 and Caco2 using neutral red uptake assay. Compounds, MCEN(6), MCPT(5a), MCPT(5b) showed better growth inhibitory activity on A549 and Caco2 growth compared to control values. While compound MCPY(7) exerted the best cytotoxic activity against A549 cells after 48 h. The expression levels of HIF-1α, ß-Catenin, MYC, Cyclin D1 and MMP7 genes in A549 cells were examined using QRT-PCR. The compounds MCEN(6) and MCPY(7) down regulated levels of ß-Catenin, MYC, Cyclin D1 and MMP7 genes and up-regulated levels of HIF-1α when treated with A549 cells compared to control values. Also, these biological studies confirmed through docking stimulation with different proteins and showed least binding energy with amino acids and attached with NH2 and OH of cellulose with hydrogen bond interaction. Moreover, optimization of compounds using DFT/6-311(G) showed the stability of them and identifies their physical descriptors which showed excellent correlation with experimental results. Noteworthy, compounds, MCEN(6) and MCPY(7) were most promising anticancer agents against lung cancer through the regulation of apoptosis, cell cycle, proliferation, progression, chemo-resistance, and angiogenesis.
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Antineoplásicos , Neoplasias , Humanos , Ciclina D1/genética , beta Catenina , Células CACO-2 , Metaloproteinase 7 da Matriz/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/química , Apoptose , Proliferação de Células , Linhagem Celular Tumoral , Simulação de Acoplamento MolecularRESUMO
BACKGROUND: Biopolymers are promising candidates that can be fabricated into hydrophilic matrices and used for many applications due to their distinctive properties such as non-toxic, biodegradable, biocompatibility, and low cost. A promising composite of chitosan and carrageenan with self-crosslinking has been prepared. METHODS AND RESULTS: In this study, a rigorous approach for an inexpensive and non-toxic combination of different amounts of clove oil with two polyelectrolytes including chitosan and carrageenan in the form of beads has been prepared. The structure and the surface morphology of the beads were investigated using FTIR, X-ray diffraction (XRD), and SEM. Moreover, antimicrobial, antiviral activity, and molecular docking were evaluated. Antibacterial results revealed that chitosan/carrageenan@clove oil beads have antimicrobial activity as well as chitosan/carrageenan without clove oil against Escherichia coli AATCC25922, Pseudomonas aeruginosa AATCC27853, Staphylococcus aureus ATCC25923, Bacillus subtilis AATCC6051, and Candida albicans ATCC90028. Furthermore, maximum non-toxic concentration (MNTC) of chitosan/carrageenan@clove oil beads was (31.25 µg ml-1 ) which exhibited promising antiviral activity against Herpes simplex virus-1 (HSV-1), and was significantly higher than chitosan/carrageenan without clove oil, where antiviral activity was 82.94% and 57.64%, respectively. Eventually, docking study and computational calculation have been used to show the reactivity of the molecules. CONCLUSIONS: The developed chitosan/carrageenan@clove oil beads have shown promising properties to be used as carriers of drug delivery, tissue engineering, and regenerative medicine.
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Anti-Infecciosos , Quitosana , Antibacterianos , Anti-Infecciosos/farmacologia , Antivirais/farmacologia , Carragenina , Óleo de Cravo , Simulação de Acoplamento MolecularRESUMO
In this work, biocompatible, antimicrobial, and antiviral nanocomposites were prepared through two steps. In the first step, periodate oxidation of cellulose was performed to get dialdehyde cellulose (DAC). The second step included the reaction of DAC with sulfur-containing amino acids included Cysteine (Cys) and Methionine (Meth) in the presence of graphene oxide (GO). The prepared nanocomposites were characterized via FT-IR, SEM, TEM, and TGA. Antimicrobial and antiviral activities for all designed nanocomposites besides DAC were carried out. Both DAC/GO/Cys and DAC/GO/Meth exhibited a promising antimicrobial activity against Gram-negative (E. coli and P. aeruginosa), Gram-positive (B. subtilis and S. aureus), and unicellular fungi (C. Albicans and C. neoformans), while the DAC/GO/Cys/Meth nanocomposite was the lowest. Moreover, all designed nanocomposites have a strong antiviral activity against Herpes simplex virus 1(HSV-1) at minimum nontoxic concentration. Additionally, Computational procedures and Molecular docking showed the reactivity and stability of the molecules that have biological activity against Gram-positive, Gram-negative, and HSV-1. As well as DAC incorporation with amino acid enhanced their reactivity and their interaction.
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Anti-Infecciosos , Grafite , Nanocompostos , Aminoácidos , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Antivirais/farmacologia , Celulose , Escherichia coli , Simulação de Acoplamento Molecular , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureusRESUMO
The current rationale is exploring new eco-friendly UV- shielding films based on cellulose and thiazolidine. Cellulose was oxidized to dialdehyde cellulose (DAC) and tricarboxy cellulose (TCC) by periodate and TEMPO/periodate/hypochlorite, respectively. While E-3-amino-5-(phenyldiazenyl)-2-thioxothiazolidin-4-one (TH) was synthesized by coupling diazonium salt with the 5-methylene of 2-thioxo-4-thiazolidinone. DAC was then coupled with TH via Schiff base reaction and incorporated onto TCC with different ratios to get UV-shielding films. 1HNMR, infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA) were used to investigate the chemical structure of the synthesized materials. In addition, the films' morphology, thermal, mechanical, and UV-shielding properties were investigated. The UV-shielding studies revealed that the film with 10% DAC-TH has 99.88, 99.99, and 96.19% UV-blocking (UVB), UV-absorbance (UVA), and Ultra-violet protection (UPF), respectively. Moreover, the prepared films demonstrated promising antimicrobial activity against Escherichia coli, S. aureus, P. aeruginosa, and Candida albicans. Finally, the prepared films showed no cytotoxic effects on normal human skin fibroblast's HFB-4 cell line.
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Staphylococcus aureus , Raios Ultravioleta , Celulose/química , Celulose/farmacologia , Fenômenos Químicos , Humanos , Tiazolidinas/farmacologiaRESUMO
Development of the oxidation process of cellulose has occurred to decrease the reaction time. Dialdehyd cellulose (DAC) has synthesized via periodate oxidation under microwave irradiation and Graphen oxide (GO) was synthesized by modified Hummer method. A new composite of DAC/GO has prepared from GO and DAC. The structure and morphology of DAC, GO and DAC/GO composite were evaluated via Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. Mechanical properties of DAC and DAC/GO were investigated. Additionally, the computational calculations of cellulose, DAC and GO by DFT/B3LYP/6-31G (d) basis sets were investigated. DAC/GO composite demonstrated specific antimicrobial activity against Gram-positive and Gram-negative bacteria. The molecular docking of DAC shows binding energy interaction (- 4.1, - 4.0, and - 4.0) Kcal/mol against microbial protein of Pseudomonas aeruginosa as Gram-negative bacteria PDB (2W7Q), and Staphylococcus aureus as Gram-positive bacteria PDB (1BQB) as well as Covid-19 PDB (7BZ5) respectively. DAC shows drug-like behavior when it is compared with binding energy interaction of Hydroxychloroquine against Covid-19, as a standard drug.
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Micheal addition reaction of the microcrystalline cellulose (MCC) (1) with acrylonitrile (2) afford the corresponding microcrystalline cyanoethyl cellulose (MCEC) which cyclized via [2+3] cycloaddition reaction to afford the corresponding microcrystalline tetrazole cellulose (MCTC) with a different homogenous catalyst. The desired products were confirmed through the spectral data, FT-IR, 1HNMR, 13CNMR and also scanning electron microscope with different pore sizes. All MCTC exhibited excellent in vitro antitumor activity against hepatic and breast tumor cell such as HCT-116, HeG2, and MDA-MB-231; respectively. Additionally, the molecular docking of most effective compounds MCTC to evaluate its potential interaction against doxorubicin drug-binding protein (PDBID: 5OM5) and Crystal structure of Cu (I) CusA (PDBID: 3K0I). The computational calculation of optimized monomer (mCTC) to elucidate HOMO-LUMO gap, ESP and the vibrational frequencies was studied through DFT/ B3LYP/6-31G(d) and HF/6-31G(d) basis sets.
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Celulose/química , Tetrazóis/química , Sítios de Ligação , Catálise , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Celulose/metabolismo , Celulose/farmacologia , Reação de Cicloadição , Doxorrubicina/química , Doxorrubicina/metabolismo , Humanos , Simulação de Acoplamento Molecular , Teoria Quântica , Eletricidade Estática , Relação Estrutura-AtividadeRESUMO
Cyanoethyl cellulose (CEC)/ magnetite (Fe3O4) flexible composite film with enhanced dielectric and magnetic properties was successfully prepared. CEC has been synthesized from micro crystalline cellulose (MCC). The effects of magnetite mass fraction on the morphology, microstructure, thermal stability, and antimicrobial activity of the as-prepared composite films were investigated. The Vibrating sample magnetometer (VSM) and broadband dielectric spectrometer was also employed to study the magnetic and dielectric properties, respectively. In addition to study the computational calculation of MCC, and CEC by DFT/ B3LYP/6-31G (d) basis sets. The results showed that, the sample that is magnetite free has a diamagnetic response to the applied magnetic field, however the other samples that is loaded with magnetite show super-paramagnetic behavior indicating that the particles' sizes of the magnetite mostly below 20 nm. Also, antimicrobial activities of composite films against (G + ve), (G-ve), were investigated.
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Antibacterianos/farmacologia , Antifúngicos/farmacologia , Celulose/análogos & derivados , Celulose/farmacologia , Óxido Ferroso-Férrico/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Aspergillus niger/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Celulose/síntese química , Teoria da Densidade Funcional , Condutividade Elétrica , Escherichia coli/efeitos dos fármacos , Óxido Ferroso-Férrico/química , Fenômenos Magnéticos , Modelos Químicos , Porosidade , Staphylococcus aureus/efeitos dos fármacosRESUMO
Microporous cellulose xerogel can be defined as low density biomaterial that can be employed for a variety of promising applications of different fields. The characteristics of xerogel are a consequence of their microstructure. An easy-to-use and reversible solid-state colorimetric sensor for ammonia gas was developed by embedding a bromocresol purple (BCP) pH-sensory chromophore into the environmental friendly carboxymethyl cellulose as bio-based polymer (CMC) matrix. The bromocresol purple was immobilized into cross-linked carboxymethyl cellulose (CMC-BCP) xerogel followed by freeze-drying to introduce a microporous network of regenerated cellulose host in which bromocresol purple chromophore was immobilized to function as a spectroscopic probe guest. Identification of ammonia gas occurred via proton shift from the hydroxyl group of the BCP dye to ammonia nitrogen. Both qualitative and quantitative activities were determined. The architectures of the prepared cellulose xerogel at different degree of substitutions (DS) was investigated using Fourier-transform infrared spectroscopy (FTIR) and scan electron microscopy (SEM), which displayed a high porosity and pores diameter in the range of 10-50 µm. The resultant CMC-BCP displayed high sensitivity for gaseous ammonia. Moreover, excellent reversibility and short detection time were also monitored. The vapochromic xerogel provided an instant color alteration signal from yellow to purple when exposed to ammonia gas or an ammonium hydroxide aqueous environment as monitored by the absorption maxima, color coordinates and color strength. The visual color change of CMC-BCP xerogel was observed to alter in the order from yellow, orange, red to purple in proportional with raising the ammonia concentration in an aqueous environment. Moreover, the CMC-BCP xerogel displayed rapid response time, concentration detection limit as low as 9.0 × 10-2 ppb for ammonia in aqueous media, and very good reversibility.
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In this work regenerated cellulose was prepared by phosphoric acid as a primarily step in preparation of biodegradable foam. Copper nanoparticles (Cu-NPs) were embedded onto the cellulosic suspensions followed by freeze drying process. The scanning electron microscopy (SEM) revealed the presence of individual chunky regenerated cellulose fibers in the dimensions of micro that enhanced tendency to aggregate during drying. X-ray diffraction (XRD) demonstrated that, the treatment of cellulose with concentrated phosphoric acid led to defibrated cellulose with lower crystallinity index than original cellulose fibers. The study provided insights about the influence of the Cu-NPs on the structure, thermal stability and the electrical contributions of the considered cellulose-based foam. The electrical and dielectric properties were studied by means of the broadband dielectric spectroscopy. The dielectric spectra were dominated by an anomalous behavior of the permittivity as illustrated versus frequency of the investigated samples. The real part of conductivity follows the universal power law at higher frequencies. The foam loaded Cu-NPs exhibit biodegradability and highly efficient antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans.
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Anti-Infecciosos/química , Celulose/química , Cobre/química , Nanopartículas Metálicas/química , Semicondutores , Anti-Infecciosos/farmacologia , Celulose/metabolismo , Cobre/farmacologia , Impedância Elétrica , LiofilizaçãoRESUMO
Collecting sweat sample for onsite testing is a sophisticated process as the analysis process must be completed in a real-time with a highly absorptive and sensitive device in order to gain a useful assessment of its content. Thus, we developed a chemical probe incorporated into microfibrillated cellulose to introduce a novel, simple, robust and flexible aerogel. This chromogenic sponge-like aerogel assay demonstrated a color change from yellow to orange, red and blue depending on the sweat biochemical changes. Novel pH sensitive tricyanofuran hydrazone probe was prepared, characterized and encapsulated in-situ within microfibrillated cellulose to follow up sweat pH changes. The solvatochromic performance in several solvents of different polarities and the reversible pH correlated color change of this tricyanofuran hydrazone probe in an acetonitrile solution was explored by UV-Vis absorption spectra. The microporous and microfibrillated sponge-like cellulose substrate was fabricated by activation of wood pulp using phosphoric acid followed by freeze-drying process. Morphological characterization, thermal stability and fiber crystallinity of the prepared aerogel were explored using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The visual color change was explored by studying the CIE LAB color space coordinates and color strength values. The cytotoxicity of the sponge-like aerogel sensor was also evaluated.