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1.
Materials (Basel) ; 14(22)2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34832303

RESUMO

Here, we report that mesoporous hollow carbon spheres (HCS) can be simultaneously functionalized: (i) endohedrally by iron oxide nanoparticle and (ii) egzohedrally by manganese oxide nanorods (FexOy/MnO2/HCS). Detailed analysis reveals a high degree of graphitization of HCS structures. The mesoporous nature of carbon is further confirmed by N2 sorption/desorption and transmission electron microscopy (TEM) studies. The fabricated molecular heterostructure was tested as the anode material of a lithium-ion battery (LIB). For both metal oxides under study, their mixture stored in HCS yielded a significant increase in electrochemical performance. Its electrochemical response was compared to the HCS decorated with a single component of the respective metal oxide applied as a LIB electrode. The discharge capacity of FexOy/MnO2/HCS is 1091 mAhg-1 at 5 Ag-1, and the corresponding coulombic efficiency (CE) is as high as 98%. Therefore, the addition of MnO2 in the form of nanorods allows for boosting the nanocomposite electrochemical performance with respect to the spherical nanoparticles due to better reversible capacity and cycling performance. Thus, the structure has great potential application in the LIB field.

2.
Int J Mol Sci ; 22(12)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200719

RESUMO

The potential of bacterial cellulose as a carrier for the transport of ibuprofen (a typical example of non-steroidal anti-inflammatory drugs) through the skin was investigated. Ibuprofen and its amino acid ester salts-loaded BC membranes were prepared through a simple methodology and characterized in terms of structure and morphology. Two salts of amino acid isopropyl esters were used in the research, namely L-valine isopropyl ester ibuprofenate ([ValOiPr][IBU]) and L-leucine isopropyl ester ibuprofenate ([LeuOiPr][IBU]). [LeuOiPr][IBU] is a new compound; therefore, it has been fully characterized and its identity confirmed. For all membranes obtained the surface morphology, tensile mechanical properties, active compound dissolution assays, and permeation and skin accumulation studies of API (active pharmaceutical ingredient) were determined. The obtained membranes were very homogeneous. In vitro diffusion studies with Franz cells were conducted using pig epidermal membranes, and showed that the incorporation of ibuprofen in BC membranes provided lower permeation rates to those obtained with amino acids ester salts of ibuprofen. This release profile together with the ease of application and the simple preparation and assembly of the drug-loaded membranes indicates the enormous potentialities of using BC membranes for transdermal application of ibuprofen in the form of amino acid ester salts.


Assuntos
Aminoácidos/química , Anti-Inflamatórios não Esteroides/farmacologia , Celulose/química , Ésteres/química , Ibuprofeno/farmacologia , Absorção Cutânea/efeitos dos fármacos , Pele/efeitos dos fármacos , Administração Cutânea , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/química , Bactérias/metabolismo , Sistemas de Liberação de Medicamentos , Ibuprofeno/administração & dosagem , Ibuprofeno/química , Suínos
3.
Int J Mol Sci ; 22(12)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200927

RESUMO

Bacterial cellulose membranes (BCs) are becoming useful as a drug delivery system to the skin. However, there are very few reports on their application of plant substances to the skin. Komagataeibacter xylinus was used for the production of bacterial cellulose (BC). The BC containing 5% and 10% ethanolic extract of Epilobium angustifolium (FEE) (BC-5%FEE and BC-10%FEE, respectively) were prepared. Their mechanical, structural, and antioxidant properties, as well as phenolic acid content, were evaluated. The bioavailability of BC-FESs using mouse L929 fibroblasts as model cells was tested. Moreover, In Vitro penetration through the pigskin of the selected phenolic acids contained in FEE and their accumulation in the skin after topical application of BC-FEEs was examined. The BC-FEEs were characterized by antioxidant activity. The BC-5% FEE showed relatively low toxicity to healthy mouse fibroblasts. Gallic acid (GA), chlorogenic acid (ChA), 3,4-dihydroxybenzoic acid (3,4-DHB), 4-hydroxybenzoic acid (4-HB), 3-hydroxybenzoic acid (3-HB), and caffeic acid (CA) found in FEE were also identified in the membranes. After topical application of the membranes to the pigskin penetration of some phenolic acid and other antioxidants through the skin as well as their accumulation in the skin was observed. The bacterial cellulose membrane loaded by plant extract may be an interesting solution for topical antioxidant delivery to the skin.


Assuntos
Antioxidantes/administração & dosagem , Celulose/química , Epilobium/química , Fibroblastos/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Pele/efeitos dos fármacos , Administração Tópica , Animais , Bactérias/química , Fibroblastos/metabolismo , Camundongos , Pele/metabolismo , Suínos
4.
Nanotechnology ; 32(35)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34034236

RESUMO

Photocatalytic activity of molybdenum disulfide structures with different dimensions (0D, 1D and 2D) functionalized with polymeric carbon nitride (PCN) is presented. MoS2nanotubes (1D), nanoflakes (2D) and quantum dots (0D, QDs) were used, respectively, as co-catalysts of PCN in photocatalytic water splitting reaction to evolve hydrogen. Although, 2D-PCN showed the highest light absorption in visible range and the most enhanced photocurrent response after irradiation with light from 460 to 727 nm, QDs-PCN showed the highest photocatalytic efficiency. The detailed analysis revealed that the superior photocatalytic activity of QDs-PCN in comparison with other structures of MoS2arose from (i) the most effective separation of photoexcited electron-hole pairs, (ii) the most enhanced up-converted photoluminescence (UCPL), (iii) the highest reactivity of electrons in conduction band. Moreover, a narrowed size of QDs affected shorter diffusion path of charge carriers to active reaction sites, higher number of the sites and higher interfacial area between molybdenum disulfide and PCN.

5.
Int J Mol Sci ; 22(3)2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33535598

RESUMO

Here, we aimed to boost antibacterial performance of cellulose fibers for paper sheet application. Therefore, TiO2 nanoparticles have been used with controlled loading onto the surface of the fibers. A simple and facile composite preparation route based on ultrasound and mechanical assisted stirring has been developed. We tested cellulose paper enriched by TiO2 from 1.0 wt% to 8.0 wt%, respectively. Antibacterial performance has been studied against Staphylococcus aureus and Escherichia coli bacteria. Studies showed that all composites exhibit significant capability to reduce living cells of S. aureus and E. coli bacteria at least 60%. The simplicity, low cost, and reproducibility of the prepared method indicates the potential to be scaled up for industrial applications.


Assuntos
Antibacterianos/farmacologia , Celulose/química , Teste de Materiais , Nanopartículas Metálicas/química , Titânio/química , Anti-Infecciosos , Escherichia coli , Testes de Sensibilidade Microbiana , Papel , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus , Células-Tronco , Termogravimetria
6.
ACS Omega ; 5(44): 28730-28737, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33195926

RESUMO

Herein, we report fabrication of MoSe2 functionalized with bimetal Co/Ni particles, which shows promising electrochemical performance in oxygen and hydrogen evolution reactions (OER and HER) due to its physicochemical properties such as electronic configuration and great electrochemical stability. We propose functionalization with two transition metals, cobalt and nickel, expecting a synergic effect in electrocatalytic activity in a water splitting reaction. These electrocatalytic reactions are essential for efficient electrochemical energy storage. The thin flakes were obtained by exfoliation of bulk molybdenum diselenide. Next, after deposition of metals, precursors were carbonized. Electrochemical data reveal that the presence of Ni and Co particles boosts electrocatalyst performance, providing a great number of active sites due to their conductivity. Interestingly, the material exhibited great evolution potential and good stability in long-term tests.

7.
Sci Rep ; 10(1): 14631, 2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32884107

RESUMO

Carbon-based supercapacitors have aroused ever-increasing attention in the energy storage field due to high conductivity, chemical stability, and large surface area of the investigated carbon active materials. Herein, eucalyptus-derived nitrogen/oxygen doped hierarchical porous carbons (NHPCs) are prepared by the synergistic action of the ZnCl2 activation and the NH4Cl blowing. They feature superiorities such as high specific surface area, rational porosity, and sufficient N/O doping. These excellent physicochemical characteristics endow them excellent electrochemical performances in supercapacitors: 359 F g-1 at 0.5 A g-1 in a three-electrode system and 234 F g-1 at 0.5 A g-1 in a two-electrode system, and a high energy density of 48 Wh kg-1 at a power density of 750 W kg-1 accompanied by high durability of 92% capacitance retention through 10,000 cycles test at a high current density of 10 A g-1 in an organic electrolyte. This low-cost and facile strategy provides a novel route to transform biomass into high value-added electrode materials in energy storage fields.

8.
Molecules ; 25(5)2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32120977

RESUMO

Downsizing well-established materials to the nanoscale is a key route to novel functionalities, in particular if different functionalities are merged in hybrid nanomaterials. Hybrid carbon-based hierarchical nanostructures are particularly promising for electrochemical energy storage since they combine benefits of nanosize effects, enhanced electrical conductivity and integrity of bulk materials. We show that endohedral multiwalled carbon nanotubes (CNT) encapsulating high-capacity (here: conversion and alloying) electrode materials have a high potential for use in anode materials for lithium-ion batteries (LIB). There are two essential characteristics of filled CNT relevant for application in electrochemical energy storage: (1) rigid hollow cavities of the CNT provide upper limits for nanoparticles in their inner cavities which are both separated from the fillings of other CNT and protected against degradation. In particular, the CNT shells resist strong volume changes of encapsulates in response to electrochemical cycling, which in conventional conversion and alloying materials hinders application in energy storage devices. (2) Carbon mantles ensure electrical contact to the active material as they are unaffected by potential cracks of the encapsulate and form a stable conductive network in the electrode compound. Our studies confirm that encapsulates are electrochemically active and can achieve full theoretical reversible capacity. The results imply that encapsulating nanostructures inside CNT can provide a route to new high-performance nanocomposite anode materials for LIB.


Assuntos
Técnicas Eletroquímicas/métodos , Íons/química , Lítio/química , Nanotubos de Carbono/química , Cobalto/química , Condutividade Elétrica , Fontes de Energia Elétrica , Eletrodos , Compostos Férricos/química , Compostos de Manganês/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanocompostos/química , Nanocompostos/ultraestrutura , Nanotubos de Carbono/ultraestrutura , Óxidos/química , Estanho/química
9.
Sci Rep ; 10(1): 740, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31959835

RESUMO

In this work, few-layered molybdenum disulfide (MoS2) was functionalized with metal oxide (MxOy) nanoparticles which served as a catalyst for carbon nanotubes (CNT) growth in the chemical vapour deposition (CVD) process. The resulting MoS2/MxOy/CNT functionalized nanomaterials were used for flame retarding application in poly(lactic acid) (PLA). The composites were extruded with a twin-screw extruder with different wt% loading of the nanomaterial. Full morphology characterization was performed, as well as detailed analysis of fire performance of the obtained composites in relation to pristine PLA and PLA containing an addition of the composites. The samples containing the addition of MoS2/MxOy/CNT displayed up to over 90% decrease in carbon oxide (CO) emission during pyrolysis in respect to pristine PLA. Microscale combustion calorimetry testing revealed reduction of key parameters in comparison to pristine PLA. Laser flash analysis revealed an increase in thermal conductivity of composite samples reaching up to 65% over pristine PLA. These results prove that few-layered 2D nanomaterials such as MoS2 functionalized with CNT can be effectively used as flame retardance of PLA.

10.
Nanomaterials (Basel) ; 9(11)2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31752223

RESUMO

The fabrication of conventional or biodegradable polymers with improved thermal and fire-resistant properties is an important task for their successful application in various branches of the industry. In this work, few-layered molybdenum disulfide was functionalized with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and introduced into polyethylene and poly(lactic acid) matrixes. The obtained polyethylene composite samples displayed improved thermal stability, significant reduction in CO emissions, improved fire-resistant properties, and over 100% increases in thermal conductivity. Poly(lactic acid) composites displayed less impressive results, but have managed to improve some values, such as CO emissions, peak heat release rate, and total heat release in comparison to pristine polymer.

11.
Electron. j. biotechnol ; 41: 30-36, sept. 2019. graf, tab, ilus
Artigo em Inglês | LILACS | ID: biblio-1053564

RESUMO

Background: Yarrowia lipolytica is a nonconventional, dimorphic yeast with multiple biotechnological applications. Considering the size of Y. lipolytica cells and a plethora of its morphological forms (spherical cells or hyphae and pseudohyphae), it is highly difficult to select a suitable carrier for this useful microorganism. Bacterial cellulose (BC) is currently considered one of the most promising immobilization carriers. In the current study, the usefulness of oil- and emulsion-modified BCs as a carrier for Y. lipolytica immobilization was investigated. Static and agitated cultures were conducted in media supplemented with oil or emulsion to improve carrier porosity. Results: It was found that the application of oil- and emulsion-modified BCs correlated with significantly higher efficiency of Y. lipolytica immobilization and hence higher yield than the yield achieved with an unmodified carrier. Increased efficiency of immobilization correlated with BC porosity-related parameters, which, in turn, depended on the size of oil droplets introduced into the culture medium. Moreover, changes in porosity-related parameters caused by the addition of oil or emulsion to the medium were observed when the cultures were conducted only under static conditions and not under agitated conditions. Conclusion: The application of oil- and emulsion-modified BCs as carriers significantly increased the efficiency of Y. lipolytica immobilization as compared to unmodified BC. The addition of oil or emulsion to the culture medium can be a simple but effective method to modify the porosity of BC-based carriers.


Assuntos
Celulose/metabolismo , Yarrowia/metabolismo , Imobilização , Polímeros , Leveduras , Biotecnologia , Óleos Vegetais , Porosidade , Yarrowia/química , Nanoestruturas , Emulsões
12.
ACS Omega ; 4(6): 10225-10230, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31460114

RESUMO

Carbon nanotubes (CNTs) have been of great interest because of their unique electrical, structural, and mechanical properties. Many methods for obtaining CNTs are known. Chemical vapor deposition (CVD) has been recognized as the most popular and practical synthetic method for obtaining CNTs, with high purity, high yield, and low cost. Catalyst components are usually transient metals such as Fe, Co, and Ni, and hydrocarbons are used as a feedstock for the CNT synthesis. The metal particles are supported on the inorganic porous materials, such as alumina (Al2O3), silica (SiO2), magnesia (MgO), zeolite, and mesoporous silica. In this work, we propose a new platform for the deposition of metal nanoparticles and the growth of CTs. Molybdenum disulfide (MoS2) has gained much attention in the material fields. The principal aim of the present work is to compare the synergetic effect of MoS2 and CTs and to investigate the possibility of using the material in various fields. The obtained material was tested for its use in fire retardation. We compared the effect of adding bulk MoS2 and MoS2/CTs into the polymer matrix.

13.
World J Microbiol Biotechnol ; 35(1): 11, 2019 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-30604023

RESUMO

The aim of this study was to assess the immobilization pattern of microorganisms characterized by varying cell shapes and sizes (rod-shaped bacteria Lactobacillus delbruecki, spherical-shaped yeast Saccharomyces cerevisiae and hyphae forms of Yarrowia lipolytica) on bacterial cellulose of various material properties. The 'adsorption-incubation' method was used for the purposes of immobilization. The immobilization pattern included adsorption efficiency, ability of the immobilized cells to multiply within the carrier expressed as incubation efficiency and the degree of release of the immobilized cells from the carrier. The efficiency of adsorption and incubation was affected by the morphology of the immobilized cells and increased together with cellulose surface area. For smaller bacterial cells a higher level of loading was obtained on the same surface as compared to larger yeast cells. During incubation, the number of immobilized bacterial and yeast cells increased significantly in comparison to the number of cells adsorbed on the carrier during the adsorption step. Despite the morphological differences between the S. cerevisiae and Y. lipolytica cells, there were no statistically significant differences in the efficiency of adsorption and incubation. It was also revealed that the release ratio values obtained for L. delbruecki and S. cerevisiae increased along with cellulose surface area. Interestingly, Y. lipolytica cells in the pseudohyphae and hyphae forms penetrated deeply into the three-dimensional network of BC nanofibrils which prevented subsequent cell release. It was confirmed that carrier selection must be individually matched to the type of immobilized cells based especially on its porosity-related parameters.


Assuntos
Bactérias/química , Células Imobilizadas/citologia , Celulose/química , Adsorção , Saccharomyces cerevisiae/citologia , Yarrowia/citologia
14.
Nanomaterials (Basel) ; 8(10)2018 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-30347830

RESUMO

Here, we report a facile route for obtaining carbon spheres with fully tunable shell thickness. Using a hard template in chemical vapor deposition (CVD), hollow carbon spheres, solid carbon spheres, and intermediate structures can be obtained with optimized process time. The resulting carbon spheres with particle diameters of ~400 nm, as well as a controllable shell thickness from 0 to 70 nm, had high Brunauer⁻Emmett⁻Teller (BET) specific surface area (up to 344.8 m²·g-1) and pore volume (up to 0.248 cm³·g-1). The sphere formation mechanism is also proposed. This simple and reproducible technique can deliver carbon materials for various applications, e.g., energy storage and conversion, adsorption, catalytic, biomedical, and environmental applications.

15.
Chem Asian J ; 8(11): 2627-33, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23929713

RESUMO

Core-shell-structured mesoporous silica spheres were prepared by using n-octadecyltrimethoxysilane (C18TMS) as the surfactant. Hollow mesoporous carbon spheres with controllable diameters were fabricated from core-shell-structured mesoporous silica sphere templates by chemical vapor deposition (CVD). By controlling the thickness of the silica shell, hollow carbon spheres (HCSs) with different diameters can be obtained. The use of ethylene as the carbon precursor in the CVD process produces the materials in a single step without the need to remove the surfactant. The mechanism of formation and the role played by the surfactant, C18TMS, are investigated. The materials have large potential in double-layer supercapacitors, and their electrochemical properties were determined. HCSs with thicker mesoporous shells possess a larger surface area, which in turn increases their electrochemical capacitance. The samples prepared at a lower temperature also exhibit increased capacitance as a result of the Brunauer-Emmett-Teller (BET) area and larger pore size.

16.
ACS Appl Mater Interfaces ; 5(8): 3042-7, 2013 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-23560552

RESUMO

A novel method for the fabrication of core/shell structured mesoporous carbon spheres with solid shell using a template method has been presented. The unique molecular nanostructures are characterized by XRD, TEM, TGA, and nitrogen adsorption/desorption measurement. The formation mechanism of the mesostructured carbon spheres with a carbon shell is proposed according to the experimental results. Nanoconfinement effect, occurring in the core/shell structured template, is believed to play a key role in mediating the formation of these hierarchical carbon mesostructures, with SnO2 as a template and C2H4 as a carbon source of a mesoporous carbon core. This synthesis method is simple, straightforward, and suitable for the preparation of various nanostructures that are unique scaffolds in catalytic and electrochemical applications.

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