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Aim: Benznidazole (BNZ), a class-II drug, is the primary treatment for Chagas disease, but its low aqueous solubility presents challenges in formulation and efficacy. Nanosuspensions (NS) could potentially address these issues.Methods: BNZ-NS were prepared using a simple, organic solvents-free nano-milling approach. Physicochemical characterizations were conducted on both NS and lyophilized solid-state BNZ-nanocrystals (NC).Results: BNZ-NS exhibited particle size <500 nm, an acceptable polydispersity index (0.23), high Z-potential, and physical stability for at least 90 days. BNZ-NC showed tenfold higher solubility than pure BNZ. Dissolution assays revealed rapid BNZ-NS dissolution. BNZ-NC demonstrated biocompatibility on an eukaryotic cell and enhanced BNZ efficacy against trypomastigotes of Trypanosoma cruzi.Conclusion: BNZ-NS offers a promising alternative, overcoming limitations associated with BNZ for optimized pharmacotherapy.
[Box: see text].
Assuntos
Doença de Chagas , Nanopartículas , Nitroimidazóis , Tamanho da Partícula , Solubilidade , Tripanossomicidas , Trypanosoma cruzi , Nitroimidazóis/química , Nitroimidazóis/administração & dosagem , Doença de Chagas/tratamento farmacológico , Trypanosoma cruzi/efeitos dos fármacos , Nanopartículas/química , Tripanossomicidas/administração & dosagem , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Animais , Humanos , Suspensões , Estabilidade de Medicamentos , Química Farmacêutica/métodos , Solventes/química , LiofilizaçãoRESUMO
Lung cancer is the leading cause of cancer-related death. In addition to new innovative approaches, practical strategies that improve the efficacy of already available drugs are urgently needed. In this study, an inhalable dry powder formulation is used to repurpose flubendazole, a poorly soluble anthelmintic drug with potential against a variety of cancer lineages. Flubendazole nanocrystals were obtained through nanoprecipitation, and dry powder was produced by spray drying. Through fractional factorial design, the spray drying parameters were optimized and the impact of formulation on aerolization properties was clarified. The loading limitations were clarified through response surface methodology, and a 15% flubendazole loading was feasible through the addition of 20% L-leucine, leading to a flubendazole particle size of 388.6 nm, median mass aerodynamic diameter of 2.9 µm, 50.3% FPF, emitted dose of 83.2% and triple the initial solubility. Although the cytotoxicity of this formulation in A549 cells was limited, the formulation showed a synergistic effect when associated with paclitaxel, leading to a surprising 1000-fold reduction in the IC50. Compared to 3 cycles of paclitaxel alone, a 3-cycle model combined treatment increased the threshold of cytotoxicity by 25% for the same dose. Our study suggests, for the first time, that orally inhaled flubendazole nanocrystals show high potential as adjuvants to increase cytotoxic agents' potency and reduce adverse effects.
Assuntos
Adjuvantes Imunológicos , Nanopartículas , Pós , Adjuvantes Farmacêuticos , Paclitaxel/farmacologiaRESUMO
BACKGROUND: A drug with poor water-solubility, like Dexamethasone acetate, can present lower bioavailability conventional for pharmaceutical formulations, and the presence of polymorphs in the raw material can lead to drug quality problems. OBJECTIVE: In this study, nanocrystals of dexamethasone acetate were synthesized by high pressure homogenizer (HPH) method in surfactant poloxamer 188 (P188) solid dispersion and the bioavailable in raw material with polymorphism presence was evaluated. METHODS: The powder pre-suspension was prepared by the HPH process, and the nanoparticles formed were incorporated in P188 solutions. The nanocrystals formed were characterized by techniques of XRD, SEM, FTIR, thermal analysis by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), dynamic light scattering (DLS) to analyze the particle size and zeta potential, and in vitro evaluation by dissolution studies. RESULTS: The characterization techniques were adequate to show the presence of raw material with physical moisture between two dexamethasone acetate polymorphs. The nanocrystals formed in the presence of the P188 in the formulation showed a considerable increase in the rate of dissolution of the drug in the medium and in the size of the stable nanocrystals, even in the presence of dexamethasone acetate polymorphs. CONCLUSION: The results showed that it was possible to produce dexamethasone nanocrystals by HPH process with regular size by the presence of the small amount of P188 surfactant. This article presents a novelty in the development of dexamethasone nanoparticles that have different polymorphic forms in their physical composition.
Assuntos
Nanopartículas , Poloxâmero , Solubilidade , Poloxâmero/química , Dexametasona , Tensoativos , Nanopartículas/químicaRESUMO
Quinoa starch nanocrystals (QSNCs), obtained by acid hydrolysis, were used as a reinforcing filler in cassava starch films. The influence of QSNC concentrations (0, 2.5, 5.0, 7.5 and 10%, w/w) on the film's physical and surface properties was investigated. QSNCs exhibited conical and parallelepiped shapes. An increase of the QSNC concentration, from 0 to 5%, improved the film's tensile strength from 6.5 to 16.5 MPa, but at 7.5%, it decreased to 11.85 MPa. Adequate exfoliation of QSNCs in the starch matrix also decreased the water vapor permeability (~17%) up to a 5% concentration. At 5.0% and 7.5% concentrations, the films increased in roughness, water contact angle, and opacity, whereas the brightness decreased. Furthermore, at these concentrations, the film's hydrophilic nature changed (water contact angle values of >65°). The SNC addition increased the film opacity without causing major changes in color. Other film properties, such as thickness, moisture content and solubility, were not affected by the QSNC concentration. The DSC (differential scanning calorimetry) results indicated that greater QSNC concentrations increased the second glass transition temperature (related to the biopolymer-rich phase) and the melting enthalpy. However, the film's thermal stability was not altered by the QSNC addition. These findings contribute to overcoming the starch-based films' limitations through the development of nanocomposite materials for future food packaging applications.
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Enhancing the current signal response for semiconductors is the key factor for designing and fabrication of efficient electrode in electrochemical sensors. By the aid of doping with binary metal oxides, the conductivity of the resultant titanium oxide (TiO2) based nanocomposite will deliver fast electron transfer rate at the heterojunction interface. Herein, by taking advantage of mesoporous structure in TiO2, cubic shaped multivalent cerium oxide (CeO2) was incorporated into the porous cavity by simple ground assisted solvothermal process, which resulted in enormous enhancement in the current response towards detection of 2-aminophenol. The advantage of CeO2 on TiO2 not only involves the loading of binary metal oxide on its mesoporous sites, but also facilitates the formation of CeO2 nanocrystals which induce larger surface area and high electroactive sites with rapid diffusion of target species through pores. As a result, CeO2-TiO2 on modified GC electrode exhibits drastic enhancement in the current response for oxidation of 2-aminophenol with large decrease in the onset potential than TiO2/GC electrode. Furthermore, the CeO2-TiO2 modified electrode shows significant behavior for sensing of 2-aminophenol with wide linear range of 0.01-500 µM. The sensitivity and detection limit were calculated to be 0.603 µA µM cm-2 and 3.5 nM respectively. This work establishes the facile strategy for decoration of binary metal oxide-based nanocomposites as effective electrode and also possible to create new opportunities in the designing and fabrication of variety of efficient electrode in various electrochemical applications.
Assuntos
Nanopartículas Metálicas , Titânio , Aminofenóis , Técnicas Eletroquímicas/métodos , Nanopartículas Metálicas/química , Óxidos/química , Titânio/químicaRESUMO
Cellulose nanostructures obtained from lignocellulosic biomass by the enzymatic route can offer advantages in terms of material properties and processing sustainability. However, most of the enzymatic cocktails commonly used in the saccharification of biomass are designed to promote the complete depolymerization of the cellulose structure into soluble sugars. Here, investigation was made of the way that the action of different commercially available cellulase enzyme cocktails can affect the production of nanocellulose. For this, enzymatic cocktails designed for complete or partial saccharification were compared, using eucalyptus cellulose pulp as a model feedstock. The results showed that all the enzymatic cocktails were effective in the formation of nanocellulose structures, with the complete saccharification enzymes being more efficient in promoting the coproduction of glucose (36.5 g/L, 87% cellulose conversion). The presence of auxiliary enzymes, especially xylanases, acted cooperatively to favor the production of nanostructures with higher crystallinity (up to 79%), higher surface charge (zeta potential up to -30.9 mV), and more uniform dimensions within the size range of cellulose nanocrystals (80 to 350 nm). Interestingly, for the enzymatic cocktails designed for partial saccharification, the xylanase activity was more important than the endoglucanase activity in the production of nanocellulose with improved properties. The findings showed that the composition of the enzymatic cocktails already used for complete biomass saccharification can be suitable for obtaining nanocellulose, together with the release of a glucose stream, in a format compatible with the biorefinery concept.
Assuntos
Celulase , Nanoestruturas , Biomassa , Celulase/química , Celulose/química , Glucose , HidróliseRESUMO
In a recent paper, novel polyester nanocomposites reinforced with up to 3 wt% of cellulose nanocrystals (CNCs) extracted from conifer fiber were characterized for their crystallinity index, water absorption, and flexural and thermal resistance. The use of this novel class of nanocomposites as a possible substitute for conventional glass fiber composites (fiberglass) was then suggested, especially for the 1 and 2 wt% CNC composites due to promising bending, density, and water absorption results. However, for effective engineering applications requiring impact and tensile performance, the corresponding properties need to be evaluated. Therefore, this extension of the previous work presents additional results on Izod and tensile tests of 1 and 2 wt% CNC-reinforced polyester composites, together with a comparative cost analysis with fiberglass. The chemical effect caused by incorporation of CNCs into polyester was also investigated by FTIR. In comparison to the neat polyester, the Izod impact energy increased 50% and 16% for the 1 and 2 wt% composites, respectively. On the other hand, the tensile strength and Young's modulus remained constant within the ANOVA statistical analysis. FTIR analysis failed to reveal any chemical modification caused by up to 2 wt% CNC incorporation. The present impact and tensile results corroborate the promising substitution of a polyester composite reinforced with very low amount of CNCs for common fiberglass in engineering application.
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UsingoperandoBragg coherent x-ray diffraction imaging, we visualised three-dimensionally a single twinned-gold nanocrystal during the CO oxidation reaction. We describe the defect dynamics process occurring under operating conditions and indicate the correlation between the nucleation of highly strained regions at the surface of the nanocrystal and its catalytic activity. Understanding the twinning deformation mechanism sheds light on the creation of active sites, and could well contribute to the understanding of the catalytic behaviour of other catalysts. With the start-up of 4th generation synchrotron sources, we anticipate that coherent hard x-ray diffraction imaging techniques will play a major role in imagingin situchemical processes.
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The application of cellulose nanocrystal has lately been investigated as polymer composites reinforcement owing to favorable characteristics of biodegradability and cost effectiveness as well as superior mechanical properties. In the present work novel nanocomposites of unsaturated polyester matrix reinforced with low amount of 1, 2, and 3 wt% of cellulose nanocrystals obtained from conifer fiber (CNC) were characterized. The polyester matrix and nanocomposites were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), bending test, and thermogravimetric analysis (TGA). The result showed that the addition of only 2 wt% CNC increased the nanocomposite flexural strength by 159%, the ductility by 500% and the toughness by 1420%. Fracture analyses by SEM revealed a uniform participation of the CNC in the polyester microstructure. The resistance to thermal degradation of the CNC reinforced nanocomposites was improved in more than 20 °C as compared to neat polyester. No significant changes were detected in the water absorptions and XRD pattern of the neat polyester with incorporations up to 3 wt% CNC. These results reveal that the 2 wt% CNC nanocomposite might be a promising more ductile, lightweight and cost-effective substitute for conventional glass fiber composites in engineering applications.
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Titanium dioxide (TiO2) is manufactured worldwide as crystalline and amorphous forms for multiple applications, including tissue engineering, but our study proposes analyzing the impact of crystalline phases of TiO2 on Mesenchymal Stem Cells (MSCs). Several studies have already described the regenerative potential of MSCs and TiO2 has been used for bone regeneration. In this study, polydispersity index and sizes of TiO2 nanocrystals (NCs) were determined. Adipose tissue-derived Mesenchymal Stem Cells (AT-MSCs) were isolated and characterized in order to evaluate cellular viability and the internalization of nanocrystals (NCs). All of the assays were performed using the TiO2 NCs with 100% anatase (A), 91.6% anatase/9.4% rutile (AR), 64.6% rutile/35.4% anatase (RA), and 84.0% rutile/16% brookite (RB), submitted to several concentrations in 24-h treatments. Cellular localization of TiO2 NCs in the AT-MSCs was resolved by europium-doped NCs. Viability was significantly improved under the predominance of the rutile phase in NCs with localization restricted at the cytoplasm, suggesting that AR and RA NCs are not genotoxic and can be associated with most cellular activities and metabolic pathways, including glycolysis and cell division.
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Salmonella spp. is an important foodborne agent of salmonellosis, whose sources in humans often include products of avian origin. The control of this bacterium is difficult especially when Salmonella spp. is organized into biofilms. We hypothesized that the novel nanocomposites of ZnO nanocrystals doped with silver (Ag) and silver oxide (AgO) nanocrystals (ZnO:Ag-AgO) synthesized by the coprecipitation method could control or prevent the formation of Salmonella Enteritidis (SE) and Salmonella Heidelberg (SH) biofilm and its entry into turkey eggs. The diffraction characteristics of ZnO and AgO showed sizes of 28 and 30 nm, respectively. The Zn to Ag substitution into the ZnO crystalline structure was evidenced by the ionic radius of Ag+2 (1.26 Å), which is greater than Zn+2 (0.74 Å). For the SE analyses post-biofilm formation, the ZnO:Ag-AgO was not able to eliminate the biofilm, but the bacterial load was lower than that of the control group. Additionally, SE was able to infiltrate into the eggs and was found in both albumen and yolk. For the SH analyses applied onto the eggshells before biofilm formation, the ZnO:Ag-AgO treatment prevented biofilm formation, and although the bacterium infiltration into the eggs was observed in all treated groups, it was significantly smaller in ZnO:Ag-AgO pre-treated eggs, and SH could not reach the yolk. There was no difference in pore size between groups; therefore, the inhibition of biofilm formation and the prevention of bacterium entry into the egg were attributable to the use of ZnO:Ag-AgO, which was not influenced by the egg structure. Although the amount of Ag and Zn in the shell of the ZnO:Ag-AgO group was greater in relation to the control, this difference was not detected in the other egg components. In the search for new measures that are effective, safe and viable for controlling microorganisms in poultry farming, the application of a nanocomposite of Ag-doped ZnO and AgO nanocrystals appears as an alternative of great potential to prevent Salmonella sp biofilms in eggshells and other surfaces.
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Orotic acid (OA), a heterocyclic compound also known as vitamin B13, has shown potent antimalarial and cardiac protection activities; however, its limited water solubility has posed a barrier to its use in therapeutic approaches. Aiming to overcome this drawback, OA freeze-dried nanocrystal formulations (FA, FB, and FC) were developed by using the high-energy milling method. Polysorbate 80 (FA) and povacoat® (FC) were used alone and combined (FB) as stabilizers. Nanocrystals were fully characterized by dynamic light scattering, laser diffraction, transmission electron microscopy, thermal analysis (thermogravimetry and derivative thermogravimetry, and differential scanning calorimetry), and X-ray powder diffraction revealing an acceptable polydispersity index, changes in the crystalline state with hydrate formation and z-average of 100-200 nm, a remarkable 200-time reduction compared to the OA raw material (44.3 µm). Furthermore, saturation solubility study showed an improvement of 13 times higher than the micronized powder. In addition, cytotoxicity assay revealed mild toxicity for the FB and FC formulations prepared with povacoat®. OA nanocrystal platform can deliver innovative products allowing untapped the versatile potential of this drug substance candidate.
Assuntos
Nanopartículas/química , Ácido Orótico/química , Solubilidade/efeitos dos fármacos , Água/química , Animais , Varredura Diferencial de Calorimetria/métodos , Linhagem Celular , Química Farmacêutica/métodos , Composição de Medicamentos/métodos , Liofilização/métodos , Camundongos , Tamanho da PartículaRESUMO
Os nanocristais são partículas de fármacos cristalinos, com tamanho médio na faixa de submicrons, geralmente entre 200 e 500 nm, estabilizados por agentes estéricos ou eletrostáticos adsorvidos na superfície das partículas do fármaco. Sua dimensão reduzida proporciona propriedades especiais, como a adesividade às mucosas e o aumento de área superficial e da solubilidade de saturação, o que melhora significativamente a biodisponibilidade de fármacos pouco solúveis em água. Outra aplicação emergente dos nanocristais é na melhoria da entrega e da retenção de fármacos em tecidos e células tumorais. Estudos demonstraram que o flubendazol é um fármaco capaz de induzir a morte celular em tumores malignos e retardar o seu crescimento, por meio da alteração que provoca na estrutura dos microtúbulos e pela inibição da polimerização da tubulina. Foi demonstrada sua atividade antiproliferativa em linhagens de leucemia, mieloma, câncer intestinal, câncer de mama e neuroblastoma. O flubendazol é também um fármaco eficaz contra os helmintos, demonstrando atividade superior na eliminação dos vermes adultos, quando comparado com a dietilcarbamazina. Embora o flubendazol pareça ser uma molécula promissora, é um fármaco praticamente insolúvel em água (0,005 mg/mL). Para atingir o efeito terapêutico desejado, é necessário o desenvolvimento de uma formulação com melhores solubilidade e biodisponibilidade. Nesse sentido, o presente trabalho apresenta o preparo e a caracterização físico-química de nanocristais de flubendazol por meio da microfluidização. Foram realizados ensaios exploratórios para avaliar a performance de diferentes agentes estabilizantes nas suspensões: o polissorbato 80, o polaxamer 188 e o D-α tocoferol polietilenoglicol 1.000 succinato (TPGS). A avaliação da distribuição do tamanho de partícula foi realizada por espalhamento de luz laser (LLS), espalhamento de luz dinâmica (DLS), análise de rastreamento de nanopartículas (NTA) e microscopia eletrônica de varredura (MEV). A utilização do TPGS favoreceu a obtenção de uma nanossuspensão com o menor diâmetro hidrodinâmico médio das partículas, de 253,9 ± 3,0 nm. Nos estudos exploratórios, também foram determinados os parâmetros ótimos de moagem do microfluidizador, sendo estabelecidos: 35.000 psi de pressão, temperatura do produto de 30°C (± 5°C) e tempo de recirculação de 2 horas/100 gramas. Objetivando alcançar o menor diâmetro hidrodinâmico médio dos nanocristais, executou-se um planejamento estatístico no qual foi avaliada a influência da concentração de flubendazol (% p/p) e de TPGS (% p/p) na formulação. A análise revelou a significativa influência da concentração do TPGS na redução do tamanho de partícula e na estabilidade físico-química da nanossuspensão. Ensaios complementares de solubilidade demonstraram que o nanocristal proporcionou incremento na solubilidade de 2,3 e 3,2 e 5,2 vezes em HCl 0,1 N, tampão fosfato pH 6,8 e tampão fosfato salino pH 7,4, respectivamente. No ensaio de dissolução conduzido em HCl 0,1 N e 0,1% TPGS, observou-se significativo incremento, de 41% de fármaco dissolvido após 60 minutos, quando comparado com o flubendazol micronizado. As características do estado sólido do nanocristal foram avaliadas por meio de análise térmica (calorimetria exploratória diferencial e termogravimetria) e difratometria de raios X, não sendo observadas significativas alterações da estrutura cristalina. O presente trabalho também avaliou a efetividade dos nanocristais de flubendazol em tumores de pulmão, demonstrando sua expressiva capacidade de retardar o crescimento e diminuir o tamanho desses tumores em camundongos xenotransplantados
Os nanocristais são partículas de fármacos cristalinos, com tamanho médio na faixa de submicrons, geralmente entre 200 e 500 nm, estabilizados por agentes estéricos ou eletrostáticos adsorvidos na superfície das partículas do fármaco. Sua dimensão reduzida proporciona propriedades especiais, como a adesividade às mucosas e o aumento de área superficial e da solubilidade de saturação, o que melhora significativamente a biodisponibilidade de fármacos pouco solúveis em água. Outra aplicação emergente dos nanocristais é na melhoria da entrega e da retenção de fármacos em tecidos e células tumorais. Estudos demonstraram que o flubendazol é um fármaco capaz de induzir a morte celular em tumores malignos e retardar o seu crescimento, por meio da alteração que provoca na estrutura dos microtúbulos e pela inibição da polimerização da tubulina. Foi demonstrada sua atividade antiproliferativa em linhagens de leucemia, mieloma, câncer intestinal, câncer de mama e neuroblastoma. O flubendazol é também um fármaco eficaz contra os helmintos, demonstrando atividade superior na eliminação dos vermes adultos, quando comparado com a dietilcarbamazina. Embora o flubendazol pareça ser uma molécula promissora, é um fármaco praticamente insolúvel em água (0,005 mg/mL). Para atingir o efeito terapêutico desejado, é necessário o desenvolvimento de uma formulação com melhores solubilidade e biodisponibilidade. Nesse sentido, o presente trabalho apresenta o preparo e a caracterização físico-química de nanocristais de flubendazol por meio da microfluidização. Foram realizados ensaios exploratórios para avaliar a performance de diferentes agentes estabilizantes nas suspensões: o polissorbato 80, o polaxamer 188 e o D-α tocoferol polietilenoglicol 1.000 succinato (TPGS). A avaliação da distribuição do tamanho de partícula foi realizada por espalhamento de luz laser (LLS), espalhamento de luz dinâmica (DLS), análise de rastreamento de nanopartículas (NTA) e microscopia eletrônica de varredura (MEV). A utilização do TPGS favoreceu a obtenção de uma nanossuspensão com o menor diâmetro hidrodinâmico médio das partículas, de 253,9 ± 3,0 nm. Nos estudos exploratórios, também foram determinados os parâmetros ótimos de moagem do microfluidizador, sendo estabelecidos: 35.000 psi de pressão, temperatura do produto de 30°C (± 5°C) e tempo de recirculação de 2 horas/100 gramas. Objetivando alcançar o menor diâmetro hidrodinâmico médio dos nanocristais, executou-se um planejamento estatístico no qual foi avaliada a influência da concentração de flubendazol (% p/p) e de TPGS (% p/p) na formulação. A análise revelou a significativa influência da concentração do TPGS na redução do tamanho de partícula e na estabilidade físico-química da nanossuspensão. Ensaios complementares de solubilidade demonstraram que o nanocristal proporcionou incremento na solubilidade de 2,3 e 3,2 e 5,2 vezes em HCl 0,1 N, tampão fosfato pH 6,8 e tampão fosfato salino pH 7,4, respectivamente. No ensaio de dissolução conduzido em HCl 0,1 N e 0,1% TPGS, observou-se significativo incremento, de 41% de fármaco dissolvido após 60 minutos, quando comparado com o flubendazol micronizado. As características do estado sólido do nanocristal foram avaliadas por meio de análise térmica (calorimetria exploratória diferencial e termogravimetria) e difratometria de raios X, não sendo observadas significativas alterações da estrutura cristalina. O presente trabalho também avaliou a efetividade dos nanocristais de flubendazol em tumores de pulmão, demonstrando sua expressiva capacidade de retardar o crescimento e diminuir o tamanho desses tumores em camundongos xenotransplantados
Assuntos
Animais , Masculino , Camundongos , Ensaios de Seleção de Medicamentos Antitumorais , Nanopartículas/metabolismo , Antimetabólitos Antineoplásicos/classificação , Nanotecnologia/classificação , Neoplasias Pulmonares/fisiopatologiaRESUMO
Iron-doped bismuth sulphide (Bi2-xFexS3) nanocrystals have been successfully synthesized in a glass matrix using the fusion method. Transmission electron microscopy images and energy dispersive spectroscopy data clearly show that nanocrystals are formed with an average diameter of 7-9 nm, depending on the thermic treatment time, and contain Fe in their chemical composition. Magnetic force microscopy measurements show magnetic phase contrast patterns, providing further evidence of Fe incorporation in the nanocrystal structure. The electron paramagnetic resonance spectra displayed Fe3+ typical characteristics, with spin of 5/2 in the 3d5 electronic state, thereby confirming the expected trivalent state of Fe ions in the Bi2S3 host structure. Results from the spin polarized density functional theory simulations, for the bulk Fe-doped Bi2S3 counterpart, corroborate the experimental fact that the volume of the unit cell decreases with Fe substitutionally doping at Bi1 and Bi2 sites. The Bader charge analysis indicated a pseudo valency charge of 1.322|e| on FeBi1 and 1.306|e| on FeBi2 ions, and a spin contribution for the magnetic moment of 5.0 µB per unit cell containing one Fe atom. Electronic band structures showed that the (indirect) band gap changes from 1.17 eV for Bi2S3 bulk to 0.71 eV (0.74 eV) for Bi2S3:FeBi1 (Bi2S3:FeBi2). These results are compatible with the 3d5 high-spin state of Fe3+, and are in agreement with the experimental results, within the density functional theory accuracy.
Assuntos
Bismuto/química , Ferro/química , Nanopartículas/química , Sulfetos/química , Espectroscopia de Ressonância de Spin Eletrônica , Vidro , Modelos Teóricos , Tamanho da Partícula , TermodinâmicaRESUMO
The feasibility of integration of cellulosic ethanol production with the manufacture of cellulose nanofibers (CNF) and cellulose nanocrystals (CNC) was evaluated using eucalyptus cellulose pulp as feedstock and employing the biochemical route alone. For the enzymatic hydrolysis step, experimental central composite design (CCD) methodology was used as a tool to evaluate the effects of solids loading (SL) and enzymatic loading (EL) on glucose release and cellulose conversion. Glucose concentrations from 45 to 125 g/L were obtained after 24 h, with cellulose conversions from 35 to 96%. Validation of the statistical model was performed at SL of 20% and EL of 10 mg protein/g, which was defined by the desirability function as the optimum condition. The sugars released were used for the production of ethanol by Saccharomyces cerevisiae, resulting in 62.1 g/L ethanol after 8 h (yield of 95.5%). For all the CCD experimental conditions, the residual solids presented CNF characteristics. Moreover, the use of a new strategy with temperature reduction from 50 to 35°C after 24 h of enzymatic hydrolysis enabled CNC to be obtained after 144 h. The CNC showed a crystallinity index of 83%, length of 260 nm, diameter of 15 nm, and aspect ratio (L/D) of 15. These characteristics are suitable for many applications, such as reinforcement in polymeric materials and other lower volume higher value bio-based products. The findings indicate the viability of obtaining ethanol and CNC using the biochemical route exclusively, potentially contributing to the future implementation of forest biorefineries. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1085-1095, 2017.
Assuntos
Celulases/metabolismo , Celulose/metabolismo , Etanol/metabolismo , Eucalyptus/química , Nanopartículas/química , Celulose/química , Etanol/química , Eucalyptus/metabolismo , Hidrólise , Saccharomyces cerevisiae/metabolismoRESUMO
A terapia celular vem sendo utilizada com resultados promissores no tratamento da tendinite equina, entretanto ainda existem dúvidas quanto à persistência e ao comportamento dessas células quando implantadas no local da lesão, e quanto à sua migração para outros focos inflamatórios. O objetivo deste estudo foi avaliar a marcação das células-tronco mesenquimais (CTMs) com nanocristal antes e após o implante em lesões tendíneas experimentais do tendão flexor digital superficial (TFDS) de equinos, bem como observar a possibilidade de migração das CTMs marcadas para outro foco de lesão, o membro contralateral do mesmo animal. Para isso, foi realizada a indução de lesão experimental no TFDS em ambos os membros torácicos de cinco equinos e, após sete dias, foram implantadas as CTMs autólogas marcadas com o nanocristal Qtracker 655 em um dos membros dos animais. Após sete dias do implante, foi realizada a biópsia tendínea para posterior avaliação histopatológica, utilizando-se microscopia com fluorescência. Também foi realizado o teste de viabilidade celular antes e após a incubação com o nanocristal. As CTMs marcadas e injetadas no tecido tendíneo mantiveram sua fluorescência sete dias após seu implante, e não ocorreu migração para o membro contralateral. O uso do nanocristal para a marcação das CTMs derivadas da medula óssea equina mostrou-se efetivo pelo fato de essa nanopartícula não ter alterado a viabilidade celular e por ela ter permanecido ativa durante o período implantado.(AU)
Cell therapy has been used with promising results in the treatment of equine tendinitis. However, there are still doubts about the persistence and behavior of these cells implanted in the injured tissue and their migration to other inflamed sites. The aim of this study was to evaluate the labeling of mesenchymal stem cells (MSCs) with nanocrystals before and after implantation in experimental tendinitis of the superficial digital flexor tendon (SDFT) of horses, observing the migration possibility of MSCs marked to another lesion, performed on the contralateral limb of the same animal. An experimental lesion was induced in SDFT in both forelimbs of five horses, and after seven days autologous MSCs labeled with Qtracker(r) 655 were implanted in one member of the animals. Tendon biopsy was performed for subsequent histopathological evaluation using fluorescence microscopy seven days after the implant. Cell viability test was also performed before and after incubation with the cell labeling kit. MSCs labeled and injected into the tendon tissue maintained their fluorescence seven days after their implantation and there was no migration to the contralateral limb. The use of nanocrystals for labeling MSCs was effective because it does not alter cell viability and remains active during the experimental period.(AU)
Assuntos
Animais , Cavalos/lesões , Tendinopatia/induzido quimicamente , Tendinopatia/terapia , Células-Tronco , Medula Óssea , Nanopartículas , Movimento Celular , Biópsia , Microscopia de FluorescênciaRESUMO
A terapia celular vem sendo utilizada com resultados promissores no tratamento da tendinite equina, entretanto ainda existem dúvidas quanto à persistência e ao comportamento dessas células quando implantadas no local da lesão, e quanto à sua migração para outros focos inflamatórios. O objetivo deste estudo foi avaliar a marcação das células-tronco mesenquimais (CTMs) com nanocristal antes e após o implante em lesões tendíneas experimentais do tendão flexor digital superficial (TFDS) de equinos, bem como observar a possibilidade de migração das CTMs marcadas para outro foco de lesão, o membro contralateral do mesmo animal. Para isso, foi realizada a indução de lesão experimental no TFDS em ambos os membros torácicos de cinco equinos e, após sete dias, foram implantadas as CTMs autólogas marcadas com o nanocristal Qtracker 655 em um dos membros dos animais. Após sete dias do implante, foi realizada a biópsia tendínea para posterior avaliação histopatológica, utilizando-se microscopia com fluorescência. Também foi realizado o teste de viabilidade celular antes e após a incubação com o nanocristal. As CTMs marcadas e injetadas no tecido tendíneo mantiveram sua fluorescência sete dias após seu implante, e não ocorreu migração para o membro contralateral. O uso do nanocristal para a marcação das CTMs derivadas da medula óssea equina mostrou-se efetivo pelo fato de essa nanopartícula não ter alterado a viabilidade celular e por ela ter permanecido ativa durante o período implantado...
Cell therapy has been used with promising results in the treatment of equine tendinitis. However, there are still doubts about the persistence and behavior of these cells implanted in the injured tissue and their migration to other inflamed sites. The aim of this study was to evaluate the labeling of mesenchymal stem cells (MSCs) with nanocrystals before and after implantation in experimental tendinitis of the superficial digital flexor tendon (SDFT) of horses, observing the migration possibility of MSCs marked to another lesion, performed on the contralateral limb of the same animal. An experimental lesion was induced in SDFT in both forelimbs of five horses, and after seven days autologous MSCs labeled with Qtracker(r) 655 were implanted in one member of the animals. Tendon biopsy was performed for subsequent histopathological evaluation using fluorescence microscopy seven days after the implant. Cell viability test was also performed before and after incubation with the cell labeling kit. MSCs labeled and injected into the tendon tissue maintained their fluorescence seven days after their implantation and there was no migration to the contralateral limb. The use of nanocrystals for labeling MSCs was effective because it does not alter cell viability and remains active during the experimental period...
Assuntos
Animais , Medula Óssea , Movimento Celular , Cavalos/lesões , Nanopartículas , Células-Tronco , Tendinopatia/induzido quimicamente , Tendinopatia/terapia , Biópsia , Microscopia de FluorescênciaRESUMO
REASONS FOR PERFORMING STUDY: Mesenchymal stem cells (MSCs) have been used to treat equine tendonitis with promising results; however, little is known about the potential migration of these cells. OBJECTIVES: To assess the possible migration of MSCs from an implantation site in the superficial digital flexor tendon (SDFT) to a lesion in the SDFT of the contralateral limb. STUDY DESIGN: In vivo experimental study. METHODS: Adipose-derived MSCs were isolated from 4 healthy horses. Lesions were induced in the SDFTs of both forelimbs, followed by intralesional implantation of autologous adipose-derived MSCs labelled with nanocrystals into one of the limbs. Flow cytometry of the peripheral blood mononuclear cells and fluorescence microscopy of biopsies of the SDFT lesions were used to search for the labelled cells. RESULTS: Labelled cells were detected among the peripheral blood mononuclear cells in all animals, but labelled cells were present only in the SDFTs that were treated with the intralesional implants. CONCLUSION: Nanocrystals were a valuable in vivo marker of MSCs to be used for tendonitis treatment. Although migration of MSCs to the bloodstream was observed, it was not possible to identify the labelled cells in the untreated tendons.
Assuntos
Movimento Celular/fisiologia , Doenças dos Cavalos/terapia , Transplante de Células-Tronco Mesenquimais/veterinária , Células-Tronco Mesenquimais/fisiologia , Tendinopatia/veterinária , Tecido Adiposo/citologia , Animais , Células Cultivadas , Feminino , Cavalos , Masculino , Células-Tronco Mesenquimais/citologia , Tendinopatia/terapiaRESUMO
The possibility of combining nanotechnology with nanomedicine opens a broad field of research which may truly revolutionize our society. The neural system plays a crucial role in the human body, and most related diseases can dramatically change the quality of life. Thus, the present study reports a novel approach for using neurotransmitters as ligands in the synthesis of surface-modified fluorescent nanocrystals for potential use in cell labeling applications. Briefly, CdS quantum dots (QDs) were prepared using L-glutamic and L-aspartic as surface capping agents via a one-step chemical processing method, which resulted in stable aqueous colloidal systems at room temperature and ambient pressure. UV-visible spectroscopy, photoluminescence spectroscopy (PL), Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM) were used to characterize the synthesis and relative stability of peptide-capped CdS nanocrystals. The results demonstrate that both ligands were effective in nucleating and stabilizing CdS quantum dots in colloidal aqueous suspensions, with an estimated dimension below 3.3 nm and with fluorescence activity. Thus, novel nanohybrids were developed based on QDs bioconjugated to surface-active neurotransmitter moieties suitable for investigation as potential biomarkers in cell targeting and signaling applications.