Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Int J Mol Sci ; 24(21)2023 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-37958710

RESUMO

Bone lesions have the capacity for regeneration under normal conditions of the bone metabolism process. However, due to the increasing incidence of major traumas and diseases that cause bone-mineral deficiency, such as osteoporosis, scaffolds are needed that can assist in the bone regeneration process. Currently, natural polymeric scaffolds and bioactive nanoparticles stand out. Therefore, the objective of the study was to evaluate the osteoregenerative potential in tibiae of healthy and ovariectomized rats using mineralized collagen and nanohydroxyapatite (nHA) scaffolds associated with elastin. The in-vivo experimental study was performed with 60 20-week-old Wistar rats, distributed into non-ovariectomized (NO) and ovariectomized (O) groups, as follows: Controls (G1-NO-C and G4-O-C); Collagen with nHA scaffold (G2-NO-MSH and G5-O-MSH); and Collagen with nHA and elastin scaffold (G3-NO-MSHC and G6-O-MSHC). The animals were euthanized 6 weeks after surgery and the samples were analyzed by macroscopy, radiology, and histomorphometry. ANOVA and Tukey tests were performed with a 95% CI and a significance index of p < 0.05. In the histological analyses, it was possible to observe new bone formed with an organized and compact morphology that was rich in osteocytes and with maturity characteristics. This is compatible with osteoconductivity in both matrices (MSH and MSHC) in rats with normal conditions of bone metabolism and with gonadal deficiency. Furthermore, they demonstrated superior osteogenic potential when compared to control groups. There was no significant difference in the rate of new bone formation between the scaffolds. Ovariectomy did not exacerbate the immune response but negatively influenced the bone-defect repair process.


Assuntos
Durapatita , Elastina , Feminino , Ratos , Animais , Humanos , Ratos Wistar , Colágeno , Osteogênese , Regeneração Óssea , Ovariectomia , Alicerces Teciduais , Engenharia Tecidual
2.
Int J Mol Sci ; 21(10)2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32443455

RESUMO

Kidney cancer rapidly acquires resistance to antiangiogenic agents, such as sunitinib, developing an aggressive migratory phenotype (facilitated by c-Metsignal transduction). The Aryl hydrocarbon receptor (AhR) has recently been postulated as a molecular target for cancer treatment. Currently, there are two antitumor agent AhR ligands, with activity against renal cancer, that have been tested clinically: aminoflavone (AFP 464, NSC710464) and the benzothiazole (5F 203) prodrug Phortress. Our studies investigated the action of AFP 464, the aminoflavone pro-drug currently used in clinical trials, and 5F 203 on renal cancer cells, specifically examining their effects on cell cycle progression, apoptosis and cell migration. Both compounds caused cell cycle arrest and apoptosis but only 5F 203 potently inhibited the migration of TK-10, Caki-1 and SN12C cells as well as the migration signal transduction cascade, involving c-Met signaling, in TK-10 cells. Current investigations are focused on the development of nano-delivery vehicles, apoferritin-encapsulated benzothiazoles 5F 203 and GW610, for the treatment of renal cancer. These compounds have shown improved antitumor effects against TK-10 cells in vitro at lower concentrations compared with a naked agent.


Assuntos
Benzotiazóis/uso terapêutico , Flavonoides/uso terapêutico , Neoplasias Renais/tratamento farmacológico , Receptores de Hidrocarboneto Arílico/efeitos dos fármacos , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Fatores de Transcrição Hélice-Alça-Hélice Básicos/efeitos dos fármacos , Benzotiazóis/administração & dosagem , Benzotiazóis/farmacologia , Flavonoides/administração & dosagem , Flavonoides/farmacologia , Humanos , Neoplasias Renais/metabolismo , Ligantes
3.
Parasitol Res ; 118(9): 2455-2466, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31402401

RESUMO

Echinococcus granulosus sensu lato and E. multilocularis are the causative agents of life-threatening cystic and alveolar echinococcoses (CE and AE), respectively, which lead to serious public health concerns across the globe. Benzimidazoles (BMZs) are the drugs of choice for the treatment of human CE and AE. Presently, the chemotherapeutic failures of BMZs against CE and AE are caused by their low aqueous solubility, poor absorption, and consequently their erratic bioavailability. Among the BMZ compounds used for CE/AE treatment, albendazole (ABZ) and mebendazole (MBZ) are the only drugs licensed for human use. Nevertheless, the administration of these BMZs for a long period of time leads to undesirable adverse effects. Therefore, there is an urgent need for designing new formulations of BMZs with increased bioavailability. To bridge these therapeutic gaps, nanoparticle enantiomers of ABZ and drug delivery systems based on nanostructured entities currently provide an interesting new formulation of already existing drugs to improve the pharmacokinetic effects of BMZs. This study provides an overview of the tested nanocompounds against E. granulosus and E. multilocularis, including their effective dose, type of nanoparticles (NPs), assay setting, and therapeutic outcomes. This review suggests that BMZ derivatives loaded in NPs can significantly improve the scolicidal and cysticidal activities compared with single BMZ. Moreover, BMZ-loaded polymeric NPs show a tendency to increase mortality rate against protoscoleces and microcysts compared with metallic formulations, nanoemulsions, lipid nanocapsules, solid lipid NPs, liposomes, and nanocrystals. In the future, the use of the newly structured entities, attained by bridging ligands to the modified surface of NPs, as well as the electromagnetically produced nanodrugs could be helpful for developing fine-tuned formulations as an alternative to the already existing drugs against these neglected parasitic infections.


Assuntos
Albendazol/uso terapêutico , Antiprotozoários/uso terapêutico , Equinococose/tratamento farmacológico , Echinococcus granulosus/efeitos dos fármacos , Echinococcus multilocularis/efeitos dos fármacos , Mebendazol/uso terapêutico , Animais , Disponibilidade Biológica , Sistemas de Liberação de Medicamentos , Desenho de Fármacos , Equinococose/parasitologia , Humanos , Lipídeos , Nanocápsulas , Nanopartículas/química
4.
Wiad Lek ; 72(8): 1504-1511, 2019 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32012500

RESUMO

Introduction: Nanometals are the most common nanoobjects, used nearly in all industrial branches. Considerable advances in the nanotechnological production have led to progressive use of nanomaterials in industry, though occupational safety of the nanoindustry staff is insufficiently studied. The aim: Estimation of labor safety during production of metal nanoparticles for the purpose of defining necessary and efficient preventive measures. Material and methods: The personnel of the hygienic departments of the O.Bogomolets National medical university have conducted numerous physiological, hygienic, biochemical, morphological and toxicological studies. The scientists have studied and revealed hazardous workplace factors of various metal nanoparticle production technologies, particularly those of metal nanoparticles: nanosilver, titanium nitride, chromium disilicide, lead sulphide, etc. Results: Results and conclusions: The authors have developed method of the occupational exposure metal nanoparticles exposure air control, assessed and analyzed health of the personnel engaged in production of the nanometals. The paper contains data of the blood cells functional activity assessment, with the detected possible molecular nanoparticles toxicity mechanisms due to the altered gene expression. The authors have studied effect of nanoaerosols onto the laboratory rats respiratory organs, evaluated their blood biochemical characteristics, liver lipid content of fatty acids as well as defined morpho-functional hepatic transformations of the laboratory animals which underwent lead sulfide nanoparticles treatment.


Assuntos
Exposição Ocupacional , Saúde Ocupacional , Animais , Humanos , Nanopartículas Metálicas , Ratos , Local de Trabalho
5.
Int J Mol Sci ; 19(2)2018 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-29393866

RESUMO

Silver is considered as antibacterial agent with well-known mode of action and bacterial resistance against it is well described. The development of nanotechnology provided different methods for the modification of the chemical and physical structure of silver, which may increase its antibacterial potential. The physico-chemical properties of silver nanoparticles and their interaction with living cells differs substantially from those of silver ions. Moreover, the variety of the forms and characteristics of various silver nanoparticles are also responsible for differences in their antibacterial mode of action and probably bacterial mechanism of resistance. The paper discusses in details the aforementioned aspects of silver activity.


Assuntos
Antibacterianos/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Nanopartículas Metálicas/química , Prata/farmacologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Antibacterianos/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Bactérias Gram-Negativas/genética , Bactérias Gram-Negativas/metabolismo , Bactérias Gram-Negativas/ultraestrutura , Bactérias Gram-Positivas/genética , Bactérias Gram-Positivas/metabolismo , Bactérias Gram-Positivas/ultraestrutura , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Nanotecnologia/métodos , Tamanho da Partícula , Prata/química
6.
J Funct Biomater ; 14(8)2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37623644

RESUMO

Tyrosine kinase inhibitor (TKI) therapy is gaining attraction in advanced cancer therapeutics due to the ubiquity of kinases in cell survival and differentiation. Great progress was made in the past years in identifying tyrosine kinases that can function as valuable molecular targets and for the entrapment of their corresponding inhibitors in delivery compounds for triggered release. Herein we present a class of drug-delivery nanocompounds based on TKI Midostaurin-loaded gold nanoparticles that have the potential to be used as theranostic agents for the targeting of the FMS-like tyrosine kinase 3 (FLT3) in acute myeloid leukemia. We optimized the nanocompounds' formulation with loading efficiency in the 84-94% range and studied the drug release behavior in the presence of stimuli-responsive polymers. The therapeutic activity of MDS-loaded particles, superior to that of the free drug, was confirmed with toxicities depending on specific dosage ranges. No effect was observed on FLT3-negative cells or for the unloaded particles. Beyond druggability, we can track this type of nanocarrier inside biological structures as demonstrated via dark field microscopy. These properties might contribute to the facilitation of personalized drug dosage administration, critical for attaining a maximal therapeutic effect.

7.
Artigo em Inglês | MEDLINE | ID: mdl-36719580

RESUMO

Breast cancer is a diverse female malignancy; its classification is based on clinical evidence and pathological elucidation. Large public drug screening data databases combined with transcriptome measures have helped develop predictive computational models. Breast cancer is frequent among women worldwide. Several genes increase breast cancer risk. The Mammalian Target of Rapamycin (popularly known as mTOR) is a risk factor mutated in numerous breast carcinoma types. This has caught the scientific community's focus, which is attempting to generate creative, potent, and bio-available ligands for future anti-cancer treatments to establish a practical therapeutic approach. mTOR is a protein kinase involved in cell proliferation, survival, metabolism, and immune response. Activating mTOR promotes cancer growth and spread. To generate a bioavailable and effective mTOR inhibitor, we used computer-aided drug design to study chromones and flavonoids, two naturally occurring chemicals with many biological activities. We used Curcuma longaderived tiny nano-molecules, which can be coated using liposomes to target mTOR to prevent breast cancer growth. The significant interactions of Curcumin were anticipated using molecular docking. It had the highest binding affinity at -12.26 kcal/mol. 100 nanoseconds of molecular dynamic modelling confirmed Curcumin and mTOR receptor interaction. Liposomes are a form of medicine carrier. To improve healthcare, more liposome-like nanostructures are being made. Nanostructures' interactions with living creatures are being studied. Half-life, tissue accumulation, and toxicity have been studied. Future medication distribution may use nanocarriers having a liposome-like form, enabling targeted nano-delivery. Curcumin's interaction with the active site increased the complex's structural stability during its expansion. Our results may help future investigations of Curcumin's efficacy as a possible lead treatment targeting mTOR receptors in breast cancer. Using Curcumin as a potential anti-cancer drug with lipid-coated nano-particles allows for tailored administration.

8.
J Tradit Chin Med ; 42(2): 167-175, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35473336

RESUMO

OBJECTIVE: To evaluate the anti-bacterial activities of titanium dioxide (TiO) nanoparticles of Origanum (O.) vulgare and Hypericum (H.) perforatum extracts, carvacrol and hypericin against Staphylococcus (S.) aureus. METHODS: In this study, TiOnanoparticles of O. vulgare and H. perforatum extracts, carvacrol and hypericin, were prepared and their antibacterial effects were evaluated against Staphylococcus (S.) aureus. In this study, scanning electron microscope, fourier transform infrared spectrometer, atomic force microscopy, dynamic light scattering and zeta potential were used to investigate the structure of synthesized drugs. RESULTS: Anti-bacterial activity of synthesized NPs was tested by minimum inhibitory concentration (MIC), minimum bactericidal concentration and disc diffusion method. MICs of TiO-NPs synthesized using O. vulgare, H. perforatum, carvacrol and hypericin and TiO were obtained 250, 62.5, 250, and 250, and 500 µg/mL, respectively. The MBCs for all of these were obtained 1000 µg/mL. CONCLUSION: Green-synthesized of TiO nanoparticles provides a promising approach to the use of O. vulgare and H. perforatum, carvacrol and hypericin as novel agents and safer antibacterial compounds, especially anti-S. aureus compounds.


Assuntos
Antineoplásicos , Hypericum , Nanopartículas , Origanum , Antracenos , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias , Cimenos , Humanos , Hypericum/química , Origanum/química , Perileno/análogos & derivados , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Óleos de Plantas , Staphylococcus aureus , Titânio
9.
J Parasit Dis ; 45(3): 845-850, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34475668

RESUMO

The use of plant extracts and the benefit of their unique properties in treating various pathogens is the return to mother nature, and an attempt to overcome the problems of side effects resulting from the use of chemical drugs and the ability of some pathogens to resist these drugs. Nanotechnology has strengthened the ability of drugs to reach the target and reduced the size and amount of dose needed for treatment. Nano-extracts of Citrullus colocynthis and Capparis spinosa at concentrations of (100, 250 and 500) ppm prepared to the treatment Trichomonas vaginalis in vitro at the time (12, 24, 72) h. Results compared with the use of 0.1% of metronidazole (500 mg). The results showed that the concentrations (100, 250, 500) ppm of C. colocynthis had an inhibitory activity for the growth rate (43.77, 69.15, 89.89) at the time (12, 24 and 72) h, respectively. The inhibitory activity of C. spinosa was (43.18, 67.41, 87.04) at the same time and concentration, compared with metronidazole (43.47, 70.40, 87.04) at the same time. Neither plants showed severe effects in hemolysis. From the results, it can be concluded that either plant can be used as an alternative to metronidazole after completing human and animal tests.

10.
Expert Opin Drug Deliv ; 18(5): 535-552, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33426936

RESUMO

Introduction: Cystic fibrosis (CF), is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and affects thousands of people throughout the world. Lung disease is the leading cause of death in CF patients. Despite the advances in treatments, the management of CF mainly targets symptoms. Recent CFTR modulators however target common mutations in patients, alleviating symptoms of CF. Unfortunately, there is still no approved treatments for patients with rare mutations to date.Areas covered: This paper reviews current treatments of CF that mitigate symptoms and target genetic defects. The use of gene and drug delivery systems such as viral or non-viral vectors and nano-compounds to enhance CFTR expression and the activity of antimicrobials against chronic pulmonary infections respectively, will also be discussed.Expert opinion: Nano-compounds tackle biological barriers to drug delivery and revitalize antimicrobials, anti-inflammatory drugs and even genes delivery to CF patients. Gene therapy and gene editing are of particular interest because they have the potential to directly target genetic defects. Nanoparticles should be formulated to more specifically target epithelial cells, and biofilms. Finally, the development of more potent gene vectors to increase the duration of gene expression and reduce inflammation is a promising strategy to eventually cure CF.


Assuntos
Fibrose Cística , Anti-Inflamatórios/uso terapêutico , Fibrose Cística/tratamento farmacológico , Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Terapia Genética , Humanos , Inflamação/tratamento farmacológico , Mutação
11.
Arch Immunol Ther Exp (Warsz) ; 69(1): 23, 2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34345944

RESUMO

The abundance of nanoparticles introduced to household products created the great expectations towards the application of nanotechnology in biology and medicine. That calls for cost-effective preliminary assessment of its cytotoxicity and biological activity. There are many attempts for creating proper guidance and standards for performing studies regarding nanoparticles. But still some important aspects crucial for in vitro testing of nanomaterials need more attention. Particulate nature is an obvious and widely unappreciated property of nanoparticles. In the context of in vitro studies, this property is critical, and it should be, but rarely is, considered when designing, performing, describing or interpreting the experiments involving the solid nanoparticles. First, we should be aware of relatively small and limited number of nanoparticles in the experimental setup. Even crude estimation of its number will be useful for proper interpretation of results. Second, we should not presume even distribution of particles in the solution, moreover we should expect that sedimentation and aggregation play an important role in interactions of nanoparticles with cells. In that case, expressing the dose in mass/volume units may lead as astray. Finally, the relation of size, weight, and number of nanoparticles makes comparisons of activity of nanoparticles of different sizes very complex. Estimations of number of nanoparticles in the dose should be an integral part of experiment design, its validation and interpretation.


Assuntos
Nanopartículas , Nanoestruturas , Técnicas In Vitro , Nanotecnologia , Tamanho da Partícula
12.
Methods Mol Biol ; 2240: 43-55, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33423225

RESUMO

Intravital microscopy (IVM) is an essential experimental approach for evaluating, in real time, cell interactions in the blood and rheological parameters in the microcirculation of the living animals. Different tissues are surgically exposed to the visualization of the microvascular network in optical microscopies connected to video cameras and image software. By evaluating in situ microcirculatory network, IVM allows the visualization and quantification of physiological and pathological processes in the blood or in the adjacent tissues considering the whole system. Therefore, IVM has been used to evaluate the effects and mechanisms of actions in the microvascular network caused by pharmacological or toxic chemical agents. In this chapter, different experimental approaches are described to study the toxic effects and mechanisms of xenobiotics in the microcirculatory network.


Assuntos
Microscopia Intravital/métodos , Microvasos/efeitos dos fármacos , Nanoconjugados/toxicidade , Testes de Toxicidade/métodos , Xenobióticos/toxicidade , Animais , Microscopia Intravital/instrumentação , Microvasos/diagnóstico por imagem , Reologia/métodos , Xenobióticos/farmacocinética
13.
Foods ; 9(4)2020 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-32290530

RESUMO

The Special Issue entitled: "Development of Food Chemistry, Natural Products, and Nutrition Research" is focused on the recent development of food chemistry research, including natural products' sources and nutrition research, with the objectives of triggering interest towards new perspectives related to foods and opening a novel horizon for research in the food area. The published papers collected in this Special Issue are studies that refer to different aspects of food, ranging from food chemistry and analytical aspects, to composition, natural products, and nutrition, all examined from different perspectives and points of view. Overall, this Special Issue gives a current picture of the main topics of interest in the research and proposes studies and analyses that may prompt and address the efforts of research in the food area to find novel foods and novel applications and stimulate an environmentally-friendly approach for the re-use of the by-products of the agro-food area. This notwithstanding, the main challenge is currently addressed to achieve a full comprehension of the mechanisms of action of food components, the nutrients, outlining their high potential impact as preventive and/or therapeutic tools, not only as a source of macro- and/or micro-nutrients, which are necessary for all the metabolic and body functions.

14.
Nanomaterials (Basel) ; 10(9)2020 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-32906838

RESUMO

Cerenkov luminescence imaging and Cerenkov photodynamic therapy have been developed in recent years to exploit the Cerenkov radiation (CR) generated by radioisotopes, frequently used in Nuclear Medicine, to diagnose and fight cancer lesions. For in vivo detection, the endpoint energy of the radioisotope and, thus, the total number of the emitted Cerenkov photons, represents a very important variable and explains why, for example, 68Ga is better than 18F. However, it was also found that the scintillation process is an important mechanism for light production. Nanotechnology represents the most important field, providing nanosctructures which are able to shift the UV-blue emission into a more suitable wavelength, with reduced absorption, which is useful especially for in vivo imaging and therapy applications. Nanoparticles can be made, loaded or linked to fluorescent dyes to modify the optical properties of CR radiation. They also represent a useful platform for therapeutic agents, such as photosensitizer drugs for the production of reactive oxygen species (ROS). Generally, NPs can be spaced by CR sources; however, for in vivo imaging applications, NPs bound to or incorporating radioisotopes are the most interesting nanocomplexes thanks to their high degree of mutual colocalization and the reduced problem of false uptake detection. Moreover, the distance between the NPs and CR source is crucial for energy conversion. Here, we review the principal NPs proposed in the literature, discussing their properties and the main results obtained by the proponent experimental groups.

15.
Polymers (Basel) ; 11(10)2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31547089

RESUMO

The aim of this study was to investigate the physical and mechanical properties of thermally modified beech wood impregnated with silver nano-suspension and to examine their relationship with the crystallinity of cellulose. Specimens were impregnated with a 400 ppm nanosilver suspension (NS); at least, 90% of silver nano-particles ranged between 20 and 100 nano-meters. Heat treatment took place in a laboratory oven at three temperatures, namely 145, 165, and 185 °C. Physical properties and mechanical properties of treated wood demonstrated statistically insignificant fluctuations at low temperatures compared to control specimens. On the other hand, an increase of temperature to 185 °C had a significant effect on all properties. Physical properties (volumetric swelling and water absorption) and mechanical properties (MOR and MOE) of treated wood demonstrated statistically insignificant fluctuations at low temperatures compared to control specimens. This degradation ultimately resulted in significant decrease in MOR, impact strength, and physical properties. However, thermal modification at 185 °C did not seem to cause significant fluctuations in MOE and compression strength parallel to grain. As a consequence of the thermal modification, part of amorphous cellulose was changed to crystalline cellulose. At low temperatures an increased crystallinity caused some of the properties to be improved. Crystallinity also demonstrated a decrease in NS-HT185 in comparison to HT185 treatment. TCr indices in specimens thermally treated at 145 °C revealed a significant increase as a result of impregnation with nanosilver suspension. This improvement in TCr index resulted in a noticeable increase in MOR and MOE values. Other properties did not show significant fluctuations, suggesting that the effect of the increased crystallinity and cross-linking in lignin was more than the negative effect of the low cell-wall polymer degradation caused by thermal modification. Change of amorphous cellulose to crystalline cellulose, as well as cross-linking in lignin, partially ameliorated the negative effects of thermal degradation at higher temperatures and therefore, compression parallel to grain and modulus of elasticity did not decrease significantly. Overall, it can be concluded that increased crystallinity and cross-linking in lignin can compensate for some decreased properties caused by thermal modification, but it would be significantly dependent on the temperature under which modification is carried out. Impregnating specimens with silver nano-suspension prior to thermal modification enhanced the effects of thermal modification as a result of improved thermal conductivity.

16.
Heliyon ; 5(7): e02053, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31334378

RESUMO

The spread of graphene in low-density polyethylene (LDPE) improves LDPE/graphene nanocompounds' thermal/mechanical/electrical characteristics. The images of scanning electron microscopy (SEM) verify full graphene exfoliation at 1000 °C. Inclusion graphene develops crystallinity; increases the local order of lattice and thermal stability of LDPE/graphene nanocompounds. The consistent distributions and further inclusion of graphene caused the great heat breakdown strength, increasing heat breakdown activation energy and a superior melting point (Tm) for LDPE nanocompounds. Percolation occurs with the graphene incorporation of 0.5 wt%. The complex viscosity test showed Newtonian behavior for LDPE at a very low frequency. But, graphene inclusion to LDPE changed the viscosity performance from liquid-like to solid-like which caused a decrease in the melt flow rate (MFR) values for all LDPE/graphene nanocompounds.

17.
J Trace Elem Med Biol ; 49: 98-104, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29895379

RESUMO

The therapy with nanocompounds is widely used to treat Fe deficiency and an emerging trend to inhibit tumor growth. The present work aims to address the management of different FeONP, comparing sucrose covered FeONP and Fe nanoparticles in the form of the ferritin with non-particulated inorganic Fe (II) by enterocytes-like colon cancer cell lines (Caco-2 and HT-29). Iron uptake results revealed significantly higher Fe incorporation in the case of nanoparticulated Fe, first in the form of FeONP and second in the form of ferritin with respect to inorganic Fe (II). Furthermore, the intracellular Fe fractionation, conducted by size exclusion chromatography coupled on line to inductively coupled plasma mass spectrometry (SEC-ICP-MS) showed a significant increase of the Fe-ferritin peak upon exposure of cells to the following compounds ferritin > FeONP > FeSO4. Such results point out that the sucrose coated FeONP released Fe into the cell cytosol that was used to replenish the existing cytosolic ferritin without inducing changes in the protein concentration. On the other hand, the increase of the Fe-ferritin peak in cells exposed to ferritin as iron source is due to a significant increase on the intracellular protein concentration, as proved by using an ICP-MS linked ferritin sandwich immune assay. Cell viability experiments conducted with concentrations up to 1000 µmol L-1 (as Fe) of each compound under scrutiny did not reveal significant differences among Fe species regarding global cellular toxicity. However, significant cell DNA damage was detected when treating the cells with FeONP (500 µmol L-1).


Assuntos
Enterócitos/metabolismo , Ferritinas/metabolismo , Ferro/química , Ferro/metabolismo , Nanopartículas/química , Sacarose/química , Células CACO-2 , Sobrevivência Celular/fisiologia , Ensaio Cometa , Citosol/metabolismo , Dano ao DNA/genética , Dano ao DNA/fisiologia , Células HT29 , Humanos , Microscopia Eletrônica de Transmissão , Nanopartículas/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo
18.
Toxicol In Vitro ; 50: 318-327, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29499336

RESUMO

Different sunscreens are employed to prevent photo damage (cancer, inflammation, etc.), including ZnO. ZnO is safe when applied as micro-size particle. To overcome some visual problems of ZnO micro-size particles, this sunscreen has been introduced as nano-size particles. Unfortunately, ZnO nanoparticles have raised some health concerns, due to Zn+2 release. On the other hand, it has been shown that ZnO metallic lattice change by metal doping decreases its solubility and toxicity. Therefore, we have decided here to develop new ZnO metallic lattice to reduce its cytotoxicity. In this study, Ag+1-promoted Zn-based nanocompounds [Zn(O):Ag] were synthesized as a novel compound and were characterized. XRD analysis showed that Ag+1 ion percolates into ZnO crystalline lattice and changes its lattice properties (strength bond, vacancies, and etc.). Cell culture studies and MTT assay on human skin (HFF-1) cells exposed to UVA radiation showed that [Zn(O):Ag] was increased cells viability in the presence of UVA radiation compared to ZnO. Actually, Ag+1 ion has catalyzed photoactivity of ZnO compound. UV-blocking tests showed that UVA-absorbance of [Zn(O):Ag] has increased compared to ZnO. Dichlorofluoroscein diacetate-ROS assay and Zn+2 release experiments in the presence of cells showed that [Zn(O):Ag] has reduced Zn+2 ions release into culture medium and its toxicity. Our study shows that doped ZnO nanostructure has the potential to be applied as a safe and effective nanoparticulate sunscreen.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Raios Ultravioleta , Óxido de Zinco/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Humanos , Nanopartículas Metálicas/química , Tamanho da Partícula , Espécies Reativas de Oxigênio/metabolismo , Prata/química , Pele/citologia , Protetores Solares/química , Zinco/química , Óxido de Zinco/química
19.
Biosci. j. (Online) ; 30(6): 1919-1932, nov./dec. 2014. ilus
Artigo em Inglês | LILACS | ID: biblio-948539

RESUMO

Nanotechnologies involve the manipulation of matter at a very small scale, generally between 1 and 100 nanometers. They exploit novel properties and functions that occur in matter at this scale. The application of nanotechnology in the areas of food and food packaging is growing rapidly, and in the area of food security, these applications include the detection of microorganisms, environmental protection, water purification, encapsulation of nutrients and food packing. Nanotechnology is opening up a world of new possibilities for the food industry, but the entry of nanoparticles into the food chain can result in a buildup of toxic contaminants in food and harm human health. This review focuses on the nanoencapsulation of bioactive compounds, nanosensor especially to detect foodborne pathogens, applications of nanotechnology in food packing and highlight some of aspects of toxicology.


A nanotecnologia envolve a manipulação da matéria em uma escala muito pequena, geralmente entre 1 e 100 nanômetros. Ela explora novas propriedades e funções que ocorrem na matéria nesta escala nanometrica. A aplicação da nanotecnologia nas áreas de alimentos, embalagens para alimentos e segurança alimentar têm crescido rapidamente. Estas aplicações incluem a detecção de microrganismos, proteção ambiental, purificação de água, encapsulamento de nutrientes e embalagem para alimentos. A nanotecnologia está abrindo novas possibilidades para a indústria de alimentos, mas, a entrada de nanopartículas na cadeia alimentar pode resultar em um acúmulo de contaminantes que podem ser tóxicos e prejudicar a saúde humana. Esta revisão enfoca a nanoencapsulação de compostos bioativos, nanosensores, especialmente para detecção de patógenos em alimentos, aplicação da nanotecnologia na área de embalagens para alimentos e destaca alguns aspectos sobre toxicologia.


Assuntos
Indústria Alimentícia , Embalagem de Alimentos , Nanotecnologia , Nanocompostos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA