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1.
J Infect Public Health ; 13(9): 1243-1246, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32798183

RESUMO

The outbreak of the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is thought to have occurred first in Wuhan, China in December 2019, before spreading to over 120 countries in the months that followed. It was declared a "public health emergency of international concern" by the World Health Organization on January 31, 2020 and recognized as a pandemic on March 11, 2020. The primary route of SARS-CoV-2 transmission from human to human is through inhalation of respiratory droplets. Devising protective technologies for stopping the spread of the droplets of aerosol containing the viral particles is a vital requirement to curb the ongoing outbreak. However, the current generations of protective respirator masks in use are noted for their imperfect design and there is a need to develop their more advanced analogues, with higher blockage efficiency and the ability to deactivate the trapped bacteria and viruses. It is likely that one such design will be inspired by nanotechnologies. Here we describe a new design from Egypt, utilizing a reusable, recyclable, customizable, antimicrobial and antiviral respirator facial mask feasible for mass production. The novel design is based on the filtration system composed of a nanofibrous matrix of polylactic acid and cellulose acetate containing copper oxide nanoparticles and graphene oxide nanosheets and produced using the electrospinning technique. Simultaneously, the flat pattern fabricated from a thermoplastic composite material is used to provide a solid fit with the facial anatomy. This design illustrates an effort made in a developing setting to provide innovative solutions for combating the SARS-CoV-2 pandemic of potentially global significance.


Assuntos
Cobre , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/transmissão , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Máscaras , Doenças Profissionais/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/transmissão , Betacoronavirus , Celulose/análogos & derivados , Egito , Desenho de Equipamento , Grafite , Humanos , Nanopartículas Metálicas , Nanotecnologia , Poliésteres
2.
J Environ Manage ; 274: 111153, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32784081

RESUMO

In this study, cellulose sulfate was synthesized through sulfonation of cotton, and polypyrrole was coated on the surface of fibers. Then, the optimum ratio of pyrrole to cellulose sulfate was evaluated, and the physical, chemical, and morphological properties of the composite were assessed by using FESEM, EDS, FTIR, BET, and TGA analysis. Furthermore, adsorption of hexavalent chromium using the composite adsorbent was studied by the results of designed experiments with the Box-Behnken technique to assess the effect of pH, contact time, adsorbent dose and the initial concentration of hexavalent chromium and optimize the adsorption process. The removal percentage was 99.9% under the optimum conditions (adsorbent dose, 4 g L-1; initial concentration of Cr(VI), 200 mg L-1; pH value, 2; contact time, 200 min). The results of adsorption isotherms illustrated that the adsorption process followed Redlich-Peterson, Freundlich, Radke-Prausnitz, and UT models, and the calculated maximum adsorption capacity by the Langmuir model was 198 mg g-1. Based on the kinetic and thermodynamic studies, the adsorption process followed the intraparticle diffusion model and showed the endothermic and spontaneous adsorption with an increase in entropy on the adsorbent surface. The presence of copper, nickel and zinc cations had no adverse effect on the removal percentage of hexavalent chromium significantly. The adsorbent was reused successfully in four sequential treatments. Consequently, the synthesized adsorbent is efficient due to the high efficiency of hexavalent chromium removal percentage from electroplating effluent (99.87%).


Assuntos
Águas Residuárias , Poluentes Químicos da Água/análise , Adsorção , Celulose/análogos & derivados , Cromo/análise , Galvanoplastia , Concentração de Íons de Hidrogênio , Cinética , Polímeros , Pirróis , Termodinâmica
3.
PLoS One ; 15(6): e0233952, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32498075

RESUMO

This study aimed to produce cellulose-based conductive fabrics with electrical conductivity and flexibility. Bacterial cellulose (BC) and three chemical cellulose (CC), namely methyl cellulose (MC), hydroxypropyl cellulose (HPMC) and carboxymethyl cellulose (CMC) were in situ polymerized with aniline and the four conductive cellulose fabrics were compared and evaluated. Matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy analysis confirmed that three CC-PANI composites displayed longer and more stable polymerization pattern than BC-PANI because of the different polymerization method: bulk polymerization for BC-PANI and emulsion polymerization for CC-PANI, respectively. The electrical conductivity of BC-PANI and CC-PANI were ranging from 0.962 × 10-2 S/cm to 2.840 × 10-2 S/cm. MC-PANI showed the highest electrical conductivity among the four conductive cellulose fabrics. The flexibility and crease recovery results showed that MC-PANI had the highest flexibility compared to BC-PANI, HPMC-PANI, and CMC-PANI. These results have confirmed that the electrical conductivity and flexibility were influenced by the type of cellulose, and MC-PANI was found to have the best performance in the electrical conductivity and flexibility.


Assuntos
Carboximetilcelulose Sódica/química , Celulose/análogos & derivados , Metilcelulose/química , Polissacarídeos Bacterianos/química , Têxteis , Compostos de Anilina/química , Celulose/química , Elasticidade , Condutividade Elétrica , Nanocompostos/química , Polimerização , Têxteis/análise , Dispositivos Eletrônicos Vestíveis
4.
Int J Nanomedicine ; 15: 3669-3680, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547021

RESUMO

Introduction: The exhaustion and poor homing of activated lymphocytes are critical obstacles in adoptive cell immunotherapy for solid tumors. In order to effectively deliver immune cells into tumors, we encapsulated interferon-α2b (IFN-α2b) into macroporous hydrogels as an enhancement factor and utilized low-dose irradiation (LDI) as a tumoral attractor of T cells. Methods: Hydroxypropyl cellulose hydrogels were prepared by irradiation techniques, and the cross-sectional microstructure was characterized by scanning electron microscopy. The synergistic antitumor mechanism of combination of IFN-α2b and CIK cells was evaluated by detecting the expression of activation marker CD69 on CIK cell surface and IFN-γ production by CIK cells. The in vivo antitumor activity of IFN-α2b-incorporated hydroxypropyl cellulose hydrogels combined with CIK and radiation was evaluated in an MKN-45 xenografted nude mice model. Results: The bioactivity of IFN-α2b was well maintained in ultraviolet-reactive, rapidly cross-linkable hydroxypropyl cellulose hydrogels. In vitro studies demonstrated IFN-α2b-activated T cells, as evidenced by upregulating early activation marker CD69 and secretion inflammatory cytokine IFN-γ. In vivo real-time image showed our hydrogels kept a higher amount of drug delivery at the tumor site for a long time compared with free drug injection. Low-dose irradiation promoted T cell accumulation and infiltration in subcutaneous tumors. Combination of IFN-α2b-loaded hydrogels (Gel-IFN) with T cells and LDI exhibited higher efficacy to eradicate human gastric cancer xenograted tumors with less proliferating cells and more necrotic regions compared with IFN-α2b or T cells alone. Discussion: HPC hydrogels kept the activity of IFN-α2b and stably release of IFN-α2b to stimulate T cells for a long time. At the same time, low-dose radiation recruits T cells into tumors. This innovative integration mode of IFN-α2b-loaded hydrogels and radiotherapy offers a potent strategy to improve the therapeutic outcome of T cell therapy.


Assuntos
Antineoplásicos/uso terapêutico , Reagentes para Ligações Cruzadas/química , Hidrogéis/química , Interferon-alfa/uso terapêutico , Luz , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/radioterapia , Linfócitos T/imunologia , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Celulose/análogos & derivados , Celulose/química , Relação Dose-Resposta à Radiação , Elétrons , Humanos , Interferon-alfa/farmacologia , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Linfócitos T/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
5.
J Chromatogr A ; 1623: 461174, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505278

RESUMO

A new class of chitosan derivatives with an isopropylthiourea at the 2-position and various carbamates at the 3,6-positions of the glucosamine skeleton was synthesized by the selective thiocarbamoylation of the 2-amino group. The chiral stationary phases (CSPs) were then prepared by coating the obtained chitosan 2-isopropylthiourea-3,6-dicarbamate derivatives onto silica gel. The enantioseparation property of the chitosan-based CSPs was assessed with twelve racemates by high-performance liquid chromatography (HPLC). The CSPs displayed a characteristic enantioseparation power, which seemed to be significantly affected by the 3,6-substituents of the glucosamine unit. The chitosan derivatives with the 3,6-diphenylcarbamate, except for 2-methylphenylcarbamate, possessed higher enantioseparation abilities than those with the 3,6-dicyclohexylcarbamate. Compared to other chitosan derivatives with 2-various substituents and commercialized Chiralcel OD, the chitosan 2-isopropylthiourea derivatives revealed a relatively higher enantioselectivity for some racemic compounds.


Assuntos
Quitosana/análogos & derivados , Cromatografia Líquida de Alta Pressão/métodos , Carbamatos/química , Celulose/análogos & derivados , Celulose/química , Glucosamina/química , Fenilcarbamatos/química , Sílica Gel/química , Estereoisomerismo , Tioureia/análogos & derivados
6.
J Chromatogr A ; 1623: 461154, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505273

RESUMO

Chiral stationary phases (CSPs) have always been research hotspot in enantiomer separation. Currently, most of the CSPs are based on silica platform. In this research, monodisperse, porous glycidyl methacrylate-divinylbenzene copolymer particles (poly(GMA-DVB)) were designed and prepared. Then the GMA was further reacted with ethylenediamine to introduce amino groups onto the polymer, which provide anchoring sites for cellulose derivatives. Herein, Cellulose-tris (3,5-dimethylphenylcarbamate) (CDMPC) was successfully coated onto the polymer microspheres, achieving a stable and successful CSP. The porous structure and the surface moieties of the CSPs were studied in detail. The chromatographic separation was optimized. Hexaconazole,methyl DL-mandelate,benzoin and tebuconazole have been successfully separated on the CSP column, with column efficiency as high as 10,200 plates/m, which is comparable with some silica-based CSPs. The research has indicated that the poly(GMA-DVB) is a promising candidate for constructing CSPs for chiral separation.


Assuntos
Celulose/análogos & derivados , Microesferas , Fenilcarbamatos/química , Polímeros/química , Celulose/química , Cromatografia Líquida de Alta Pressão/métodos , Compostos de Epóxi/química , Metacrilatos/química , Porosidade , Dióxido de Silício/química , Estereoisomerismo , Triazóis/química , Compostos de Vinila/química
7.
AAPS PharmSciTech ; 21(5): 149, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32435903

RESUMO

Albendazole (ABZ), an anthelmintic compound widely used in the treatment of systemic nematode infections, is included in the list of class II drugs based on the Biopharmaceutical Classification System. ABZ has limited effectiveness due to its poor water solubility and consequent low bioavailability. Bioavailability of novel ABZ microcrystals based on hydroxyethylcellulose (S4A) or chitosan (S10A) was studied in male and female mice of two inbred lines, from the murine CBi-IGE model of trichinellosis, differing in susceptibility to this parasitosis (line CBi/L, resistant; line CBi+, susceptible). ABZ microcrystals were administered orally, and albendazole sulfoxide (ABZSO) was quantified in plasma by high-performance liquid chromatography. Mice given the microcrystals showed a significant increase in maximum plasmatic concentration (Cmax) compared with those receiving pure ABZ (P < 0.01). In both genotypes, males and females given S4A had higher Cmax than those receiving S10A (P < 0.05). CBi/L showed a greater Cmax than CBi+ (significantly different only in females treated with S4A (P = 0.001)). CBi/L females attained a higher Cmax than males (P < 0.05). No sex effect was observed for this variable in CBi+ (P > 0.05). The results of the pharmacokinetic analysis indicate that the microcrystalline formulations optimize ABZ bioavailability, both in males and females, S4A being the best system in CBi/L mice and S10A in CBi+. In summary, the microcrystals increased ABZ bioavailability, and under the conditions of this investigation, both host genotype and sex influenced the pharmacokinetic parameters measured.


Assuntos
Albendazol/farmacocinética , Celulose/análogos & derivados , Quitosana/química , Albendazol/química , Animais , Área Sob a Curva , Disponibilidade Biológica , Celulose/química , Feminino , Genótipo , Masculino , Camundongos , Caracteres Sexuais
8.
J Chromatogr A ; 1622: 461125, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32381300

RESUMO

The aim of this study was to determine the impact of the origin and the manufacturing processes of the chiral stationary phases (CSPs) on their chromatographic behaviors. Hence, four chiral stationary phases based on immobilized tris (3,5-dichlorophenylcarbamate) derivative of cellulose supplied by four different manufacturers were evaluated. A set of twenty-nine compounds, including commercially available and in-house synthesized compounds, with a broad range of lipophilicity and polarity was chosen. Three main parameters were evaluated on all stationary phases: retention factor, selectivity and loading capacity. This work highlighted that the retention factor strongly varied according to the manufacturer. Regardless of the characteristic of the tested compounds i.e. neutral, acidic or basic, there was a trend in retention ability of the four chiral stationary phases: retention was increasing from CHIRAL ART Cellulose-SC, REFLECT I-Cellulose C, Chiralpak IC to Lux i-Cellulose-5. On the contrary, selectivity did not follow the same trend as retention. The difference in selectivity between each column towards one compound was quite low while the difference in resolution depended on the nature of the compounds investigated and was significant in certain cases. Finally, the four different columns presented similar and high loading capacity.


Assuntos
Celulose/análogos & derivados , Cromatografia com Fluido Supercrítico/métodos , Fenilcarbamatos/química , Celulose/química , Omeprazol/isolamento & purificação , Estereoisomerismo
9.
Chemosphere ; 251: 126309, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443244

RESUMO

Conventional techniques used for reduction of Cr(VI) in wastewater product great amounts of metal sludge due to the use of reducing chemicals. Since in electrochemical process, the reducing agent is the electron, so the main advantage of this method is its adaptability to the environment. The aim of the current study is to reduce Cr(VI) from electroplating wastewater by the electrochemical method and to adsorb Cr(III) by cellulose sulfate adsorbent. Furthermore, to enhance the reduction efficiency of Cr(VI), the cathode was modified with Pd nanoparticles. In the present study, recovery in the electrochemical column was conducted continuously and semi-continuously. In addition, the effect of pH, amperage, flow rate, and initial concentration of Cr(VI) was investigated. To remove Cr(III) from the wastewater, the cellulose sulfate adsorbent was provided from modification of cotton health wastes. The highest recovery rate (99.63%) was witnessed at pH = 1.5, 1 A amperage, flow rate of 4.24 mL min-1, and initial concentration of 50 mg L-1. The sewage was removed from the system after several consecutive cycles and during 20-55 min reached recovery efficiency of 99.99%. Based on the results, pH had the highest effect on the process. The optimum removal percentage was 85.74% occurred at a pH of 5.6, chromium concentration of 150 mg L-1, and adsorbent concentration of 400 mg L-1. The removal rate of the pollutant was 97.32%, done by cellulose sulfate adsorbent.


Assuntos
Cromo/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Adsorção , Celulose/análogos & derivados , Cromo/química , Cobre , Eletrodos , Galvanoplastia , Concentração de Íons de Hidrogênio , Nanopartículas Metálicas , Paládio , Esgotos , Poluentes Químicos da Água/química
10.
Ceska Slov Farm ; 69(1): 24-32, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32460507

RESUMO

Currently, nerve agents are often used in terrorist attacks or assassinations. In such cases, it is necessary to detect them quickly, accurately and easily right in the field. Detection tubes, which are small devices containing pellets with immobilized cholinesterase and detection reagents, meet these conditions. Their detection mechanism is based on a highly sensitive enzymatic Ellman reaction, when in the absence of cholinesterase inhibitors the pellets develop a visible yellow color, whereas in their presence the carriers retain the original color. The rate of reaction, its sensitivity and the distinct color transition are the key points of the research. In this experiment, double-coated pellets were prepared. The first coating contained the butyrylcholinesterase immobilized in hypromellose, while the second coating consisted of ethylcellulose and triethyl citrate. Based on the properties of such carriers, samples containing lactose dispersed in the ethylcellulose coating were also prepared, which was expected to have an effect on increasing the permeability of the coating and hence the detection rate and color intensity. In addition to selected physicochemical properties, carriers were evaluated for enzyme activity, sensitivity and color transition intensity. Samples showing the best properties were subjected to a 24-months stability test at three different temperatures and humidity.


Assuntos
Butirilcolinesterase/química , Celulose/análogos & derivados , Inibidores da Colinesterase/isolamento & purificação , Enzimas Imobilizadas/química
11.
Environ Sci Pollut Res Int ; 27(19): 24413-24429, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32306250

RESUMO

Zeolitic imidazolate framework-8 (ZIF-8) has a sodalite topology. ZIF-8 is composed of zinc ion coordinated by four imidazolate rings. The pore aperture of ZIF-8 is 3.4 Å, which readily retains large gas molecules like N2. In this work, mixed-matrix membranes (MMMs) have been fabricated by utilizing ZIF-8 and pristine cellulose acetate (CA) for O2/N2 separation. Membranes of pristine CA and MMMs of ZIF-8/CA at various ZIF-8 concentrations were prepared in tetrahydrofuran (THF). Permeation results of the fabricated membranes revealed increasing selectivity for O2/N2 with increasing pressure as well as ZIF-8/CA concentration up to 5% (w/w). The selectivity of O2/N2 increased 4 times for MMMs containing 5% (w/w) of ZIF-8/CA as compared with the pristine CA membrane. A thermodynamic model has also been developed to predict the permeability of gases through polymeric membranes. The results were compared with literature data as well as the pristine CA membrane produced in this work for model validation.


Assuntos
Zeolitas , Celulose/análogos & derivados , Gases , Imidazóis , Permeabilidade , Termodinâmica
12.
J Chromatogr A ; 1621: 461054, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32204880

RESUMO

The enantioselective separation of newly prepared, pharmacologically significant isopulegol-based ß-amino lactones and ß-amino amides has been studied by carrying out high-performance liquid chromatography on diverse amylose and cellulose tris-(phenylcarbamate)-based chiral stationary phases (CSPs) in n-hexane/alcohol/diethylamine or n-heptane/alcohol/ diethylamine mobile phase systems. For the elucidation of mechanistic details of the chiral recognition, seven polysaccharide-based CSPs were employed under normal-phase conditions. The effect of the nature of selector backbone (amylose or cellulose) and the position of substituents of the tris-(phenylcarbamate) moiety was evaluated. Due to the complex structure and solvation state of polysaccharide-based selectors and the resulting enantioselective interaction sites, the chromatographic conditions (e.g., the nature and content of alcohol modifier) were found to exert a strong influence on the chiral recognition process, resulting in a particular elution order of the resolved enantiomers. Since no prediction can be made for the observed enantiomeric resolution, special attention has been paid to the identification of the elution sequences. The comparison between the effectiveness of covalently immobilized and coated polysaccharide phases allows the conclusion that, in several cases, the application of coated phases can be more advantageous. However, in general, the immobilized phases may be preferred due to their increased robustness. Thermodynamic parameters derived from the temperature-dependence of the selectivity revealed enthalpically-driven separations in most cases, but unusual temperature behavior was also observed.


Assuntos
Amilose/análogos & derivados , Celulose/análogos & derivados , Cromatografia Líquida de Alta Pressão/métodos , Monoterpenos Cicloexânicos/química , Amidas/química , Amidas/isolamento & purificação , Amilose/química , Celulose/química , Lactonas/química , Lactonas/isolamento & purificação , Fenilcarbamatos , Estereoisomerismo , Temperatura , Termodinâmica
13.
Carbohydr Polym ; 234: 115886, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32070507

RESUMO

We study the dilute solution properties and entangled dynamics of hydroxypropyl cellulose (HPC), a semiflexible polymer, in aqueous solution. Intrinsic viscosity data are consistent with a polymer in θ solvent with a Kuhn length ≃22 nm. The overlap concentration, estimated as the reciprocal of the intrinsic viscosity scales with the degree of polymerisation as c* ∝ N-0.9. We evaluate different methods for estimating the entanglement cross-over, following the de Gennes scaling and hydrodynamic scaling models, and show that these lead to similar results. Above the entanglement concentration, the specific viscosity, longest relaxation time and plateau modulus scale as ηsp ≃ N3.9c4.2, τ ≃ N3.9c2.4 and GP ≃ N0c1.9. A comparison with other polymers suggests that the rheological properties displayed by HPC are common to many polysaccharide systems of varying backbone composition, stiffness and solvent quality, as long as the effect of hyper-entanglements can be neglected. On the other hand, the observed scaling laws differ appreciably from those of synthetic flexible polymers in good or θ-solvent.


Assuntos
Celulose/análogos & derivados , Hidrodinâmica , Polissacarídeos/química , Celulose/síntese química , Celulose/química , Modelos Moleculares , Estrutura Molecular , Polimerização , Polissacarídeos/síntese química , Solventes/química , Viscosidade
14.
J Colloid Interface Sci ; 565: 416-425, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31982708

RESUMO

The poor intrinsic mechanical properties of chitosan hydrogels have greatly hindered their practical applications. Inspired by nature, we proposed a strategy to enhance the mechanical properties of chitosan hydrogels by construction of a nanofibrous and cellular architecture in the hydrogel without toxic chemical crosslinking. To this end, electrospun nanofibers including cellulose acetate, polyacrylonitrile, and SiO2 nanofibers were introduced into chitosan hydrogels by homogenous dispersion and lyophilization. With the addition of 30% cellulose acetate nanofibers, the cellular structure could be maintained even in water without crosslinking, and integration of 60% of the nanofibers could guarantee the free-standing structure of the chitosan hydrogel with a low solid content of 1%. Moreover, the SiO2 nanofiber-reinforced chitosan (SiO2 NF/CS) three-dimensional (3D) matrices exhibit complete shape recovery from 80% compressive strain and excellent injectability. The cellular architecture and nanofibrous structure in the SiO2 NF/CS matrices are beneficial for human mesenchymal stem cell adhesion and stretching. Furthermore, the SiO2 NF/CS matrices can also act as powerful vehicles for drug delivery. As an example, bone morphogenetic protein 2 could be immobilized on SiO2 NF/CS matrices to induce osteogenic differentiation. Together, the electrospun nanofiber-reinforced 3D chitosan matrices exhibited improved mechanical properties and enhanced biofunctionality, showing great potential in tissue engineering.


Assuntos
Resinas Acrílicas/química , Celulose/análogos & derivados , Quitosana/química , Nanofibras/química , Dióxido de Silício/química , Engenharia Tecidual , Adesão Celular , Diferenciação Celular , Sobrevivência Celular , Células Cultivadas , Celulose/química , Humanos , Hidrogéis/química , Teste de Materiais , Células-Tronco Mesenquimais/citologia , Tamanho da Partícula , Propriedades de Superfície
15.
Mater Sci Eng C Mater Biol Appl ; 108: 110416, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31923960

RESUMO

Developing fibrous scaffolds with hierarchical structures that closely mimic natural extracellular matrix (ECM) is highly desirable. However, fabricating scaffolds with true nanofibers (<100 nm) and submicrofibers (<1 µm) remains a big challenge. In this work, to mimic the fibrillar structure of natural ECM, bacterial cellulose (BC) nanofibers were hybridized with cellulose acetate (CA) submicrofibers for the first time. The interpenetrated nano-submicron fibrous BC/CA scaffold was fabricated using the combined electrospinning and modified in situ biosynthesis method. The BC/CA scaffold has an integrated symmetrical nanostructure in which BC nanofibers (42 nm in diameter) penetrate into the submicrofibrous CA (820 nm in diameter) scaffold. The BC/CA scaffold shows an interconnected porous structure with a high porosity of >90%. Additionally, the combination of CA submicrofibers with BC nanofibers leads to significantly improved mechanical properties over nanofibrous BC and submicrofibrous CA scaffolds and enlarged pores over nanofibrous BC scaffold. In addition, the biological behaviors of prepared BC/CA on MC3T3-E1 cells were investigated. Results suggested that BC/CA scaffold is beneficial for cell migration and proliferation. Moreover, the BC/CA scaffold shows higher alkaline phosphatase (ALP) activity, and calcium depositions. In addition, the hierarchical structures can effectively improve the expression of osteogenic gene (ALP mRNA and Runx2 mRNA) and protein (ALP). We believe that the methodology might provide biomimetic morphological microenvironments for enhanced tissue regeneration.


Assuntos
Nanofibras/química , Tecidos Suporte/química , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Animais , Materiais Biomiméticos/química , Biomimética/métodos , Diferenciação Celular/fisiologia , Linhagem Celular , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Celulose/análogos & derivados , Camundongos , Osteogênese , Porosidade , Engenharia Tecidual/métodos
16.
IET Nanobiotechnol ; 14(1): 47-52, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31935677

RESUMO

In this research, the hydrothermal method was used for synthesising cellulose acetate (CA) templated nanorods like CuS fibres using vegetable extract (Brassica oleracea var. italica). These extracts act as a reducing agent in the presence of CA. Surprisingly, when the same reaction was carried out in the absence of CA and broccoli extract, structural morphology disappeared and was found as agglomerated. In the presence of cellulose templated extract mediated CuS has revealed as nanorods like fibres and was confirmed by field emission scanning electron microscope analysis. Their crystallinity property of CuS nanoparticles (NPs) and cellulose templated biosynthesised CuS NPs was analysed and compared using X-ray diffraction technique. The biological activities of the obtained product were examined for antibacterial assessment against two bacterial strains that include two-gram negative strains (E.Coli and S. aureus). The nanostructured product found to exhibit excellent antibacterial agent against all the strains. Biosynthesised nanostructure showed its efficacy against A549 lung cancer cells which might attribute to a larger surface to volume ratio of nanorods like fibres. The authors observation suggest that CuS nanorods like fibres can significantly reduce the cell growth with IC50 value of 31.2 µg/ml.


Assuntos
Antibacterianos , Sobrevivência Celular/efeitos dos fármacos , Cobre , Clivagem do DNA/efeitos dos fármacos , Nanotubos/química , Células A549 , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Proliferação de Células , Celulose/análogos & derivados , Celulose/química , Celulose/metabolismo , Cobre/química , Cobre/metabolismo , Cobre/farmacologia , Química Verde , Humanos
17.
IET Nanobiotechnol ; 14(1): 98-104, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31935685

RESUMO

A highly sensitive, non-invasive, and rapid HBV (Hepatitis B virus) screening method combining membrane protein purification with silver nanoparticle-based surface-enhanced Raman scattering (SERS) spectroscopy was developed in this study. Reproducible serum protein SERS spectra were obtained from cellulose acetate membrane-purified human serum from 94 HBV patients and 89 normal groups. Tentative assignments of serum protein SERS spectra showed that the HBV patients primarily led to specific biomedical changes of serum protein. Principal components analysis and linear discriminate analysis were introduced to analyse the obtained spectra, with the diagnostic sensitivity of 92.6% and specificity of 77.5% were achieved for differentiating HBV patients from normal groups.


Assuntos
Celulose/análogos & derivados , Hepatite B/sangue , Hepatite B/diagnóstico , Análise Espectral Raman/métodos , Biomarcadores/sangue , Proteínas Sanguíneas/análise , Celulose/química , Vírus da Hepatite B , Humanos , Nanopartículas Metálicas/química , Análise de Componente Principal , Prata/química , Proteínas Virais/sangue
18.
Bull Exp Biol Med ; 168(3): 349-351, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31938903

RESUMO

The results of the development of combined eye gel with interferon alpha-2-beta are presented. Experimental samples of the gel based on different gelling agents were prepared and their biotechnological and technological characteristics (the absence of the cytotoxic effect, aggregation stability, osmotic activity, bioadhesion, and rheological parameters) were evaluated. The composition with hydroxyethyl cellulose, Natrosol 250HHX, in a concentration of 1.5% as a gelling agent showed the best results and the best one-year stability.


Assuntos
Géis/química , Interferon alfa-2/química , Celulose/análogos & derivados , Celulose/química , Sistemas de Liberação de Medicamentos , Leucina Encefalina-2-Alanina/análogos & derivados , Leucina Encefalina-2-Alanina/química , Viscosidade
19.
Carbohydr Polym ; 230: 115628, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887871

RESUMO

The cellulose acetate (CA) nanoparticles (NPs) were prepared via the nanoprecipitation technique. The effects of solvent mixture quality and order of addition on the size evolution of CA NPs were investigated. The size of CA NPs was reduced by decreasing the nonsolvent-solvent mixture interaction parameter (χNS-mS) and by increasing the polymer-solvent mixture interaction parameter (χP-mS). The NPs prepared by the method of addition of the polymer solution to the nonsolvent were smaller than those prepared by addition of the nonsolvent to the polymer solution. The very small CA NPs with the diameter of 37 nm and very narrow PdI of 0.045 were fabricated without using any surfactant and charged groups. The role of surface tension and osmotic pressure forces on the formation of NPs were discussed. The formation mechanism of NPs could be assigned to the rapid polymer precipitation and solidification (vitrification) of the nuclei.


Assuntos
Celulose/análogos & derivados , Nanopartículas/química , Celulose/química , Pressão Osmótica , Polimerização , Solventes/química , Tensão Superficial , Vitrificação
20.
Carbohydr Polym ; 230: 115617, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887888

RESUMO

Oral controlled release formulations have been at the center of pharmaceutical research over several decades due to their distinct advantages compared to conventional dosage forms where the entire drug payload is released and absorbed rapidly following administration. Natural polysaccharides are extensively being studied as release modifiers in oral controlled release dosage forms because of their biocompatibility, biodegradability, good safety profile, low-cost availability, and production from renewable resources. Furthermore, polysaccharides can be easily modified by physical or chemical processes to suit specific needs. This article critically reviews some of the important natural polysaccharides with emphasis on their structure, major sources, properties, and applications in various oral modified release systems. The underlying drug release mechanisms from different dosage forms are also discussed. Finally, we outline the critical limitations and challenges that need to be addressed for promoting extensive applications of natural polysaccharides in commercial controlled-release formulations.


Assuntos
Alginatos/química , Celulose/análogos & derivados , Quitosana/análogos & derivados , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Polímeros Responsivos a Estímulos/química , Administração Oral , Animais , Humanos
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