Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36.699
Filtrar
1.
J Environ Manage ; 267: 110644, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32421675

RESUMO

Artisanal mining may have modified the mobility, bioavailability and bioaccessibility of potentially toxic elements (PTEs) in the Serra Pelada gold mine, eastern Amazon, Brazil, which has not yet been studied. The objectives were to perform chemical fractionation of barium (Ba), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn), and to determine the bioaccessibility of these elements in soils and mining wastes collected in agriculture, forest, mining, and urban areas from the influence zone of the Serra Pelada gold mine. Pseudo total concentrations were obtained by acid digestion, chemical fractionation was performed using the Bureau Community of Reference (BCR) sequential extraction, oral bioaccessibility was obtained by the Simple Bioaccessibility Extraction Test (SBET) and lung bioaccessibility was obtained through Gamble's solution. The pseudo total concentrations indicated contamination by Ba, Cu and Ni. The sequential extraction revealed the predominance of all elements in the residual fraction. However, Ba is in high concentrations in the greater mobility forms, ranging from 166.36 to 1379.58 mg kg-1. Regardless of the area, Cr and Cu are more oral bioaccessible in the intestinal phase, and Zn in the gastric phase. Ba, Cr and Zn are not lung bioaccessible, while Cu, Ni and Pb are bioaccessible via inhalation. The PTEs studied deserve attention not only due to the high pseudo total concentrations found (which indicate potential risk), but also the concentrations in high mobility forms and bioaccessible fractions, especially in the areas of greatest anthropogenic occupation.


Assuntos
Metais Pesados , Poluentes do Solo , Brasil , Fracionamento Químico , Monitoramento Ambiental , Ouro , Mineração , Solo
2.
Life Sci ; 251: 117635, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32272179

RESUMO

Molecular structures containing gold, such as auranofin, have been extensively studied in the diagnosis and treatment of many diseases, including cancer treatment. The pharmacological properties of the newly synthesized unique gold-ligand structures have been reported for different cancer cell lines. However, findings on bishydeten-metal salt complexes with gold are rare. In this work, the synthesis of five novel cyanide-bridged coordination compounds having the closed formulae [Ni(bishydeten)][Au(CN)2]2 (1), [Cu(bishydeten)][Au(CN)2]2 (2), [Zn(bishydeten)2Au3(CN)4][Au2(CN)3] (3), [Cd(bishydeten)0,5]2[Au(CN)2]4.2H2O (4), and [Cd(bishydeten)2][Au(CN)2]2 (5) (where bisyhdeten = N,N-bis(2-hydroxyethyl)ethylene diamine), and their characterization by elemental, infrared, ESI-MS, X-ray (for 2) and thermic measurement methods were performed. Complexes 1 and 3 are thermally more stable than the other three complexes. For these, pharmacological adequacies were also tested. The nucleic acid and protein binding affinities of the Au (I) compounds were also estimated by spectroscopic and electrophoretic techniques. Au (I) complexes were identified as strong chemotherapeutic with mild cytotoxicity, and they demonstrated a dose-dependent inhibition on the growth of cancer cells with IC50 at 0.11 to 0.47 µM. Investigation of mechanisms of action on cells revealed that Au (I) compounds managed to inhibit cell migration and led to a decrease in cytoskeletal proteins such as CK7 and CK20. However, Au (I) compounds failed to inhibit DNA topoisomerase I. Overall, and we suggest that potent antiproliferative activity, mild cytotoxicity, good solubility, and micromolar dosage of Au (I) compounds containing bisyhdeten-metal derivatives render them the potential focus of further studies as chemotherapeutic agents.


Assuntos
Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Cianatos/farmacologia , Ouro/farmacologia , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Chlorocebus aethiops , Cianatos/administração & dosagem , Cianatos/síntese química , Relação Dose-Resposta a Droga , Ouro/administração & dosagem , Humanos , Concentração Inibidora 50 , Neoplasias/patologia , Solubilidade , Células Vero
3.
Cancer Radiother ; 24(2): 99-105, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32201058

RESUMO

PURPOSE: During radiotherapy (RT) for prostate cancer (PCa), interfraction and intrafraction movements can lead to decreased target dose coverage and unnecessary over-exposure of organs at risk. New image-guided RT techniques accuracy allows planning target volume (PTV) margins reduction. We aim to assess the feasibility of a kilovoltage intrafraction monitoring (KIM) to track the prostate during RT. METHODS AND MATERIALS: Between November 2017 and April 2018, 44 consecutive patients with PCa were included in an intrafraction prostate motion study using the Truebeam Auto Beam Hold® tracking system (Varian Medical Systems, United State) triggered by gold fiducials localization on kilovoltage (kV) imaging. A 5-mm PTV was considered. A significant gating event (SGE) was defined as the occurrence of an automatic beam interruption requiring patient repositioning following the detection of one fiducial outside a 5-mm target area around the marker during more than 45seconds. RESULTS: Six patients could not benefit from the KIM because of technical issues (loss of one fiducial marker=1, hip prosthesis=4, morbid obesity causing table movements=1). The mean rate of SGE per patient was 14±19%, and the fraction average delivery time was increased by 146±86seconds. For a plan of 39 fractions of 2Gy, the additional radiation dose increased by 0.13±0.09Gy. The mean rates of SGE were 2% and 18% (P=0.002) in patients with planned fraction<90 and>90seconds respectively, showing that duration of the session strongly interfered with prostate intrafraction movements. No other significant clinical and technical parameter was correlated with the occurrence of SGE. CONCLUSION: Automated intrafraction kV imaging can effectively perform autobeam holds due to intrafraction movement of the prostate in the large majority of patients. The additional radiation dose and delivery time are acceptable. This technique may be a cost-effective alternative to electromagnetic transponder guidance.


Assuntos
Movimentos dos Órgãos , Próstata/diagnóstico por imagem , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Radioterapia Guiada por Imagem/métodos , Idoso , Idoso de 80 Anos ou mais , Fracionamento da Dose de Radiação , Estudos de Viabilidade , Marcadores Fiduciais , Ouro , Humanos , Masculino , Pessoa de Meia-Idade , Posicionamento do Paciente , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Glândulas Seminais , Fatores de Tempo , Incerteza
4.
Exp Parasitol ; 212: 107867, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32199081

RESUMO

Trichinellosis is a serious foodborne zoonotic disease. It is an important threat to public health all over the world. Although anti-Trichinella IgG detection is the most widely used method for diagnosis of trichinellosis, but there is an obvious window between clinical symptoms and positive serology. Gold nanoparticles (AuNPs) can be conjugated with antibodies affording them promising applications for bio-chemical detection. Herein, AuNPs-based ELISA was evaluated for the first time in the detection of Trichinella spiralis circulating antigen (CAg) for its potential as a diagnostic tool of experimental infection. Swiss Albino mice were orally inoculated with 100 muscle larvae/mouse. Animals were sacrificed 6, 8, 10, 12, 14, 16, 22 and 28 day-post infection (dpi). Blood samples were tested for CAg by both standard ELISA and nano-based ELISA using anti-rabbit polyclonal IgG conjugated with AuNPs. CAg was only detected by nano-based ELISA 6, 8, 10 dpi and by both formats 12-28 dpi. Nano-based assay recorded a statistically significant high sensitivity (58.33%, 91.67%) and accuracy (72.22%, 94.44%) 8 and 10 dpi, respectively in comparison to standard ELISA. Both assays showed high sensitivity and accuracy 12-28 dpi. Thus, nano-based ELISA could be considered as an early sensitive diagnostic method for experimental trichinellosis.


Assuntos
Antígenos de Helmintos/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Doenças Transmitidas por Alimentos/diagnóstico , Nanopartículas Metálicas/química , Trichinella spiralis/imunologia , Triquinelose/diagnóstico , Animais , Anticorpos Anti-Helmínticos/sangue , Modelos Animais de Doenças , Doenças Transmitidas por Alimentos/parasitologia , Ouro/química , Imunoglobulina G/sangue , Masculino , Camundongos , Músculo Esquelético/parasitologia , Coelhos , Sensibilidade e Especificidade , Suínos , Fatores de Tempo , Trichinella spiralis/isolamento & purificação , Triquinelose/transmissão , Zoonoses/parasitologia
5.
Int J Nanomedicine ; 15: 1363-1372, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32184591

RESUMO

Purpose: In this study, we constructed novel brain-targeting complexes (U2-AuNP) by conjugating aptamer U2 to the gold nanoparticle (AuNPs) surface as a promising option for GBM therapy. Materials and Methods: The properties of the U2-AuNP complexes were thoroughly characterized. Then, we detected the in vitro effects of U2-AuNP in U87-EGFRvIII cell lines and the in vivo antitumor effects of U2-AuNP in GBM-bearing mice. Furthermore, we explored the inhibition mechanism of U2-AuNP in U87-EGFRvIII cell lines. Results: We found that U2-AuNP inhibits the proliferation and invasion of U87-EGFRvIII cell lines and prolongs the survival time of GBM-bearing mice. We found that U2-AuNP can inhibit the EGFR-related pathway and prevent DNA damage repair in GBM cells. Conclusion: These results reveal the promising potential of U2-AuNP as a drug candidate for targeted therapy in GBM.


Assuntos
Antineoplásicos/farmacologia , Aptâmeros de Nucleotídeos/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Receptores ErbB/antagonistas & inibidores , Glioblastoma/tratamento farmacológico , Ouro/química , Nanopartículas Metálicas/administração & dosagem , Animais , Antineoplásicos/química , Apoptose , Aptâmeros de Nucleotídeos/química , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Proliferação de Células , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Masculino , Nanopartículas Metálicas/química , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Food Chem ; 317: 126459, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32113141

RESUMO

The widespread exposure of bisphenol A (BPA) presents a significant risk to human health. A rapid, ultra-sensitive and label-free colorimetric aptasensor using high affinity truncated aptamers was developed for BPA detection. Truncated 38-mer and 12-mer aptamers specific for BPA were obtained through rationally truncation from 63-mer BPA aptamer. The dissociation constants (Kd) of 38-mer and 12-mer aptamers were determined to be 13.17 nM and 27.05 nM. Then, truncated aptamers were used in label-free colorimetric detection assays based on gold nanoparticles (AuNPs). The limit of detections of aptasensors using 38-mer and 12-mer aptamers were 7.60 pM and 14.41 pM, which were 265-fold and 140-fold lower than that of the aptasensor using 63-mer aptamer, respectively. The recovery rates in milk, orange juice and mineralized water samples were 93.88% to 107.30%. Therefore, the developed BPA colorimetric aptasensor using truncated aptamers has great application prospects in food safety control and environmental monitoring.


Assuntos
Aptâmeros de Nucleotídeos/química , Compostos Benzidrílicos/análise , Colorimetria/métodos , Análise de Alimentos/métodos , Fenóis/análise , Animais , Aptâmeros de Nucleotídeos/metabolismo , Compostos Benzidrílicos/química , Compostos Benzidrílicos/metabolismo , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Sucos de Frutas e Vegetais/análise , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Leite/química , Simulação de Acoplamento Molecular , Fenóis/química , Fenóis/metabolismo , Sensibilidade e Especificidade
8.
Chemosphere ; 248: 126011, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32028161

RESUMO

The Giant Mine is an abandoned gold mine in Yellowknife, Northwest Territories, Canada. Throughout its operation from 1948 to 2004, the Giant Mine released heavy amounts of arsenic trioxide into the environment, thus contaminating the soil and surface water within and around the vicinity of the mine site. Chronic arsenic (As) poisoning negatively impacts wildlife health and can induce multi-organ damages including neurodegeneration and visual dysfunction depending on concentration and duration of exposure. The aim of the current study was to comparatively assess retina layer changes and prevalence of ocular lesions in wild rodent populations (i.e. muskrats and red squirrels) breeding in arsenic endemic areas of Yellowknife, near the vicinity of the abandoned Giant mine site (∼2 km radius), at an intermediate location (approximately 20 km from the mine area) as well as a reference location (spanning 52-105 km from the city of Yellowknife, Canada). Eye globes were removed from euthanized muskrats and squirrels from the three sampling locations with increasing distance from the Giant mine area. Optical Coherence Tomography (OCT) was used to attempt a pan-retinal layer assessment, and histologic examination was utilized for assessment and confirmation of ocular lesions. The retinal layers were measured and statistically compared between the groups based on sampling locations to enhance the scope of histologic evaluations. The preliminary results revealed that thicknesses of ganglion cell layer (GCL), retina nerve fibre layer (NFL), and inner retina layer (IR) were statistically reduced in the muskrats from arsenic endemic area, particularly near the vicinity of the Giant mine compared to the control group. Generalized ocular pathology was histologically confirmed in all the muskrats from the arsenic endemic areas with the manifestation of moderate to severe lymphocytic plasmacytic uveitis (LPU), keratitis and subcapsular cataracts. Inner retinal degeneration was also observed in all the muskrats from the arsenic endemic areas, while muskrats from the control group were predominantly normal. Three muskrats from the control group were noted to have a mild LPU and keratitis. Significant histopathologic changes were not detected in the squirrel eyes from the three groups except for incidental mild cornea scars from all the locations. In general, these preliminary findings confirm the presence of ocular lesions and retina abnormalities in wild muskrats in the Yellowknife area and provide the first evidence of visual dysfunction and impairment in wildlife inhabiting arsenic endemic areas of Canada.


Assuntos
Intoxicação por Arsênico/veterinária , Arsênico/toxicidade , Arvicolinae/metabolismo , Poluentes Ambientais/toxicidade , Sciuridae/metabolismo , Animais , Arsênico/análise , Arsênico/metabolismo , Trióxido de Arsênio , Cruzamento , Canadá , Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais/metabolismo , Ouro , Territórios do Noroeste , Solo
9.
Sci Total Environ ; 716: 137026, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32036137

RESUMO

The question of whether gold (Au) is more toxic as nanoparticles or in its ionic form remains unclear and controversial. The present work aimed to clarify the effects of 96 h exposure to 4, 80 and 1600 µg·L-1 of 7 nm gold nanoparticles (AuNPs) - (citrate coated (cAuNPs) or polyvinylpyrrolidone coated (PVP-AuNPs)) - and ionic Au (iAu) on gilthead seabream (Sparus aurata). Effects at different levels of biological organization (behaviour, neurotransmission, biotransformation, oxidative stress/damage and genotoxicity) were assessed. cAuNPs induced oxidative stress and damage (lipid peroxidation increase), even at 4 µg·L-1, and reduced the ability of S. aurata to swim against a water flow at 1600 µg·L-1. Exposure to cAuNPs induced more adverse effects than exposure to PVP-AuNPs. All tested concentrations of Au (nano or ionic form) induced DNA breaks and cytogenetic damage in erythrocytes of S. aurata. Generally, iAu induced significantly more effects in fish than the nano form, probably associated with the significantly higher accumulation in the fish tissues. No fish mortality was observed following exposure to AuNPs, but mortality was observed in the group exposed to 1600 µg·L-1 of iAu.


Assuntos
Dourada , Animais , Bioacumulação , Ouro , Nanopartículas Metálicas , Estresse Oxidativo
10.
Int J Nanomedicine ; 15: 729-734, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32099361

RESUMO

Background: Recently, use of nanotechnology in biomedical applications such as drug delivery and diagnostic and therapeutic tools has increased greatly. This study evaluated gold nanoparticle (GNPs)-induced nephrotoxic effects in rats in vivo, and examined protective effects of alpha-lipoic acid (α-Lip) and Vitamin E (Vit E) against nephrotoxicity, lipid peroxidation, and inflammatory kidney damage induced by GNPs. Materials and Methods: Twenty-four male Wistar-Kyoto rats (220-240 g, 12 weeks old) were dosed with 50 µL of 10 nm GNPs administered intraperitoneally with or without 200 mg/kg/day Vit E or 200 mg/kg/day α-Lip. Serum was prepared for biochemical analyses. Kidney function was evaluated through measurement of creatinine (CR), uric acid (URIC), and blood urea nitrogen (BUN). Oxidative stress and lipid peroxidation were evaluated by measurement of reduced glutathione (GSH) and malondialdehyde (MDA) in kidney tissue homogenates. Results and Conclusions: The results showed a significant rise in serum kidney function biomarkers including urea, URIC, CR, and BUN in GNP-treated rats compared to normal control rats. Furthermore, GNPs led to decreased GSH and elevated MDA levels. Vit E or α-Lip supplementation showed a beneficial effect against nephrotoxicity, lipid peroxidation, and inflammatory kidney damage induced by GNPs. This study suggests that use of natural antioxidants in combination with GNPs may be a useful tool in preventing GNPs toxicity.


Assuntos
Ouro/toxicidade , Inflamação/induzido quimicamente , Peroxidação de Lipídeos/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Ácido Tióctico/farmacologia , Vitamina E/farmacologia , Animais , Biomarcadores/metabolismo , Creatinina/sangue , Glutationa/metabolismo , Inflamação/patologia , Rim/efeitos dos fármacos , Rim/metabolismo , Masculino , Malondialdeído/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos Endogâmicos WKY , Ácido Úrico/sangue
11.
J Endod ; 46(2): 244-251.e1, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32040423

RESUMO

INTRODUCTION: This study evaluated and compared the shaping ability of the WaveOne Gold (Dentsply/Tulsa Dental Specialties, Tulsa, OK), TRUShape 3D Conforming File (Dentsply/Tulsa Dental Specialties), EdgeCoil (EdgeEndo, Albuquerque, NM), and XP-3D Shaper (Brasseler USA, Savannah, GA) endodontic file systems on oval-shaped canals using micro-computed tomographic (micro-CT) technology. METHODS: Thirty-two oval-shaped, single-canal extracted human teeth were decoronated 1 mm coronal to the cementoenamel junction and scanned via a micro-CT scanner (µCT100; Scanco Medical, Bassersdorf, Switzerland). Teeth were divided into 4 groups (n = 8) and instrumented according to the manufacturer's instructions. Coregistered images, before and after root canal preparation, were evaluated for morphometric measurements of the surface area, volume, structure model index (SMI), conicity, and percent of walls untouched using the manufacturer's evaluation software (IPL Register, Scanco Medical). Data were statistically compared between groups using 1-way analysis of variance and within groups using a paired sample t test. RESULTS: Instrumentation with all file types increased the surface area, volume, and conicity between and within groups. There was no statistically significant difference between the groups for any of the rotary instruments used (P < .05). CONCLUSIONS: Instrumentation of oval-shaped canals with WaveOne Gold, TRUShape, EdgeCoil, and XP-3D Shaper rotary endodontic instruments similarly increase the volume, surface area, and conicity. None of the file systems were capable of contacting all of the surface area in any canal.


Assuntos
Cavidade Pulpar , Ouro , Preparo de Canal Radicular , Desenho de Equipamento , Humanos , Microtomografia por Raio-X
12.
J Photochem Photobiol B ; 204: 111800, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32028188

RESUMO

Herein, we have reported the synthesis, characterization and catalytic activity of highly stable gold nanoparticles (Au NPs) using red cabbage extract (RCE) under UV irradiation. The anthocyanin groups predominantly existing in RCE play an essential role for biosynthesis of stable Au NPs. The reasons for using anthocyanins: 1) they act as chelating agents for preferentially reacting with gold ions (Au3+) to form Au3+- anthocyanin complexes, 2) as light-active reductants for reduction of Au3+ to zero valent Au0 under UV irradiation and 3) as stabilizing agent for preventing Au NPs from aggregation in high salt concentration owing to their unique salt tolerance property. We also demonstrate that how reaction time, concentration of RCE, pH value of reaction solutions and using one more reducing agent affected formation of the Au NPs. The stability of RCE Au NPs was comparatively studied with commercial (citrate stabilized) Au NPs against 100 mM salt (NaCl) solution. The RCE-Au NP showed reduction ability for conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). UV-vis spectrometry, transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential (ZT) methods were utilized to characterize the Au NPs. We demonstrated that how whole RCE (anthocyanins molecules are major component) can be used as photo-active reducing and stabilizing agents to form Au NPs in a short time under UV irradiation and strong reducing agent without additional agents.


Assuntos
Brassica/química , Ouro/química , Nanopartículas Metálicas/química , Raios Ultravioleta , Antocianinas/química , Brassica/metabolismo , Catálise , Química Verde , Nitrofenóis/química , Oxirredução , Extratos Vegetais/química , Sais/química
13.
J Phys Chem Lett ; 11(5): 1697-1701, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32039604

RESUMO

Here we demonstrate sub-10 nm spatial resolution sampling of a volume of ∼360 molecules with a strong field enhancement at the sample-tip junction by implementing noble metal substrates (Au, Ag, Pt) in photoinduced force microscopy (PiFM). This technique shows the versatility and robustness of PiFM and is promising for application in interfacial studies with hypersensitivity and super spatial resolution.


Assuntos
Metais/química , Microscopia de Força Atômica/métodos , Animais , Bovinos , Ouro/química , Platina/química , Soroalbumina Bovina/química , Dióxido de Silício/química , Prata/química
14.
J Photochem Photobiol B ; 204: 111812, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32062391

RESUMO

One of the most important barriers to the detection of the biological autoluminescence (BAL) from biosystems using a non-invasive monitoring approach, in both the in vivo and the in vitro applications, is its very low signal intensity (< 1000 photons/s/cm2). Experimental studies have revealed that the formation of electron excited species, as a result of reactions of biomolecules with reactive oxygen species (ROS), is the principal biochemical source of the BAL which occurs during the cell metabolism. Mitochondria, as the most important organelles involved in oxidative metabolism, are considered to be the main intracellular BAL source. Hence, in order to achieve the BAL enhancement via affecting the mitochondria, we prepared a novel mitochondrial-liposomal nanocarrier with two attractive features including the intra-liposomal gold nanoparticle synthesizing ability and the mitochondria penetration capability. The results indicate that these nanocarriers (with the average size of 131.1 ±â€¯20.1 nm) are not only able to synthesize the gold nanoparticles within them (with the average size of 15 nm) and penetrate into the U2OS cell mitochondria, but they are also able to amplify the BAL signals. Our results open new possibilities for the use of biological autoluminescence as a non-invasive and label-free monitoring method in nanomedicine and biotechnology.


Assuntos
Ouro/química , Lipossomos/química , Nanopartículas Metálicas/química , Mitocôndrias/metabolismo , Linhagem Celular Tumoral , Humanos , Lipossomos/metabolismo , Microscopia de Fluorescência , Espécies Reativas de Oxigênio/metabolismo
15.
Phys Chem Chem Phys ; 22(8): 4490-4500, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32067002

RESUMO

Once introduced into the human body, nanoparticles often interact with blood proteins, which in turn undergo structural changes upon adsorption. Although protein corona formation is a widely studied phenomenon, the structure of proteins adsorbed on nanoparticles is far less understood. We propose a model to describe the interaction between human serum albumin (HSA) and nanoparticles (NPs) with arbitrary coatings. Our model takes into account the competition between protonated and unprotonated polymer ends and the curvature of the NPs. To this end, we explored the effects of surface ligands (citrate, PEG-OMe, PEG-NH2, PEG-COOH, and glycan) on gold nanoparticles (AuNPs) and the pH of the medium on structural changes in the most abundant protein in blood plasma (HSA), as well as the impact of such changes on cytotoxicity and cellular uptake. We observed a counterintuitive effect on the ζ-potential upon binding of negatively charged HSA, while circular dichroism spectroscopy at various pH values showed an unexpected pattern in the reduction of α-helix content, as a function of surface chemistry and curvature. Our model qualitatively reproduces the decrease in α-helix content, thereby offering a rationale based on particle curvature. The simulations quantitatively reproduce the charge inversion measured experimentally through the ζ-potential of the AuNPs in the presence of HSA. Finally, we found that AuNPs with adsorbed HSA display lower toxicity and slower cell uptake rates, compared to functionalized systems in the absence of protein. Our study allows examining and explaining the conformational dynamics of blood proteins triggered by NPs and corona formation, thereby opening new avenues toward designing safer NPs for drug delivery and nanomedical applications.


Assuntos
Ouro/química , Ouro/metabolismo , Nanopartículas Metálicas/química , Albumina Sérica Humana/química , Humanos , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Ligação Proteica , Estrutura Terciária de Proteína , Albumina Sérica Humana/metabolismo , Eletricidade Estática , Propriedades de Superfície
16.
Chemosphere ; 250: 126142, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32105852

RESUMO

In this study, we evaluated the phytoremediation ability of three different genotypes of cowpea (Vigna unguiculata L. Walp) grown on mercury-contaminated soils from gold mining areas. In particular we compared a native genotype with two commercial lines L-019 and L-042. The plants were cultivated in soils amended at different concentrations of Hg (i.e. 0.2, 1, 2, 5 and 8 mg kg-1). After three months exposure, we determined plant growth, seed production, and Hg accumulation in different plant tissues (root, leaf, seed and stem). Indices of soil-plant metal transfer such as translocation, bioconcentration and bioaccumulation factors were calculated. Results showed that the native variety presented the highest seed production (3.8 g), however the highest plant biomass (7.9 g) was observed in line L-019, both on Hg-contaminated soil of 1 mg kg-1. The different plant tissues differed in terms of Hg concentration (root > leaf > stem). In the highest treated soil, the line L-042 accumulates higher Hg in both roots and leaves, while line L-019 accumulates more metal in stems. In line L-019, Hg concentrations in the fruit showed significant differences being higher in the valves than in the seeds. The transfer factors were generally lower than 1 and indicates the low accumulation of Hg by cowpeas. The estimated daily Hg intake through cowpea consumption showed values far below the threshold of 0.57 µg kg-1 dw day-1 recommended by the World Health Organization. Our results show cowpea V. unguiculata as a good protein-rich food substitute of Hg-contaminated fish for populations living near gold mining sites.


Assuntos
Mercúrio/metabolismo , Poluentes do Solo/metabolismo , Vigna/metabolismo , Animais , Bioacumulação , Biodegradação Ambiental , Peixes , Ouro , Mercúrio/análise , Mineração , Folhas de Planta/química , Plantas , Solo , Poluentes do Solo/análise
17.
Int J Nanomedicine ; 15: 181-197, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32021173

RESUMO

Purpose: The overarching objective of this investigation was to investigate the intervention of green nanotechnology to transform the ancient holistic Ayurvedic medicine scientifically credible through reproducible formulations and rigorous pre-clinical/clinical evaluations. Methods: We provide, herein, full details: (i) on the discovery and full characterization of gold nanoparticles-based Nano Swarna Bhasma (henceforth referred to as NSB drug); (ii) In vitro anti-tumor properties of NSB drug in breast tumor cells; (iii) pre-clinical therapeutic efficacy studies of NSB drug in breast tumor bearing SCID mice through oral delivery protocols and (iv) first results of clinical translation, from mice to human breast cancer patients, through pilot human clinical trials, conducted according to the Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homoeopathy (abbreviated as AYUSH) regulatory guidelines of the Government of India in metastatic breast cancer patients. Results: The preclinical in vitro and in vivo investigations, in breast tumor bearing mice, established unequivocally that the NSB Nano-Ayurvedic medicine-gold nanoparticles-based drug is highly effective in controlling the growth of breast tumors in a dose dependent fashion in vivo. These encouraging pre-clinical results prompted us to seek permission from the Indian Government's holistic medicine approval authority, AYUSH, for conducting clinical trials in human patients. Patients treated with the NSB drug capsules along with the "standard of care treatment" (Arm B) exhibited 100% clinical benefits when compared to patients in the treatment Arm A, thus indicating the tremendous clinical benefits of NSB drug in adjuvant therapy. Conclusion: We have succeeded in clinically translating, from mice to humans, in using proprietary combinations of gold nanoparticles and phytochemicals to develop the Nano-Ayurvedic drug: Nano Swarna Bhasma (NSB), through innovative green nanotechnology, for treating human metastatic breast cancer patients.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Ouro/farmacologia , Medicina Ayurvédica/métodos , Nanopartículas Metálicas/química , Administração Oral , Adulto , Animais , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Ouro/química , Química Verde , Humanos , Índia , Mangifera/química , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/efeitos adversos , Nanopartículas Metálicas/uso terapêutico , Camundongos SCID , Pessoa de Meia-Idade , Nanotecnologia/métodos , Resultado do Tratamento , Xantonas/química , Ensaios Antitumorais Modelo de Xenoenxerto , Adulto Jovem
18.
Int J Nanomedicine ; 15: 227-238, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32021176

RESUMO

Introduction: Multimodal imaging agent has the potential to overcome the shortage and incorporate the advantages of different imaging tools for extremely sensitive diagnosis. To achieve multimodal imaging, combining multiple contrast agents into a special nanostructure has become a main strategy; However, the combination of all of these functions into one nanoplatform usually requires a complicated synthetic procedure that results in heterogeneous nanostructure. Methods: In this study, we develop ultrasmall gold nanoclusters with 15 gold atoms (Au15NCs) functionalized with diethylenetriamine-pentaacetic acid dianhydride (DTPAA-Gd) as an optimized multimodal imaging agent to enhance imaging ability. Results: The Au15NCs-DTPAA-Gd nanohybrids possess the ultra-small size and are capable of enhancing the contrast in near-infrared fluorescence (NIRF), magnetic resonance (MR) and X-ray computed tomography (CT) imaging. Meanwhile, the integrated DTPAA-Gd component not only endow the nanohybrids to produce higher T1 relaxivity (r1 = 21.4 mM-1 s-1) than Omnipaque (r1 = 3.973 mM-1s-1) but also further enhance X-ray attenuation property of Au15NCs. Importantly, the fluorescence intensity of Au15NCs-DTPAA-Gd did not decrease compared with Au15NCs. Ultimately, in vivo imaging experiments have demonstrated that Au15NCs-DTPAA-Gd nanohybrids can be quickly eliminated from the body through the urinary system and has great potential for anatomical imaging. Conclusion: These data manifest Au15NCs-DTPAA-Gd present great potential as a multimodal contrast agent for disease diagnosis, especially for early accurate detection of tumors.


Assuntos
Meios de Contraste/química , Meios de Contraste/farmacocinética , Ouro/química , Imagem Multimodal/métodos , Nanocompostos/química , Animais , Fluorescência , Gadolínio/química , Células HEK293 , Células Hep G2 , Humanos , Imagem por Ressonância Magnética/métodos , Camundongos Endogâmicos BALB C , Poliaminas/química , Espectroscopia de Luz Próxima ao Infravermelho , Distribuição Tecidual , Tomografia Computadorizada por Raios X/métodos
19.
Int J Nanomedicine ; 15: 275-300, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32021180

RESUMO

Gold nanoparticles (AuNPs) are extensively studied nanoparticles (NPs) and are known to have profound applications in medicine. There are various methods to synthesize AuNPs which are generally categorized into two main types: chemical and physical synthesis. Continuous efforts have been devoted to search for other more environmental-friendly and economical large-scale methods, such as environmentally friendly biological methods known as green synthesis. Green synthesis is especially important to minimize the harmful chemical and toxic by-products during the conventional synthesis of AuNPs. Green materials such as plants, fungi, microorganisms, enzymes and biopolymers are currently used to synthesize various NPs. Biosynthesized AuNPs are generally safer for use in biomedical applications since they come from natural materials themselves. Multiple surface functionalities of AuNPs allow them to be more robust and flexible when combined with different biological assemblies or modifications for enhanced applications. This review focuses on recent developments of green synthesized AuNPs and discusses their numerous biomedical applications. Sources of green materials with successful examples and other key parameters that determine the functionalities of AuNPs are also discussed in this review.


Assuntos
Ouro/química , Química Verde/métodos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Animais , Bactérias/química , Sistemas de Liberação de Medicamentos , Fungos/química , Humanos , NAD/química , Fenóis/química , Plantas/química , Proteínas/química , Terpenos/química
20.
Aquat Toxicol ; 221: 105445, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32078886

RESUMO

Despite the widespread use of nanoparticles (NPs), there are still major gaps of knowledge regarding the impact of nanomaterials in the environment and aquatic animals. The present work aimed to study the effects of 7 and 40 nm gold nanoparticles (AuNPs) - citrate and polyvinylpyrrolidone (PVP) coated - on the liver proteome of the estuarine/marine fish gilthead seabream (Sparus aurata). After 96 h, exposure to AuNP elicited alterations on the abundance of 26 proteins, when compared to the control group. AuNPs differentially affected several metabolic pathways in S. aurata liver cells. Among the affected proteins were those related to cytoskeleton and cell structure, gluconeogenesis, amino acids metabolism and several processes related to protein activity (protein synthesis, catabolism, folding and transport). The increased abundance of proteins associated with energy metabolism (ATP synthase subunit beta), stress response (94 kDa glucose-regulated protein) and cytoskeleton structure (actins and tubulins) may represent the first signs of cellular oxidative stress induced by AuNPs. Although higher gold accumulation was found in the liver of S. aurata exposed to 7 nm PVP-AuNPs, the 7 nm cAuNPs were more bioactive, inducing more effects in liver proteome. Gold accumulated more in the spleen than in the other assessed tissues of S. aurata exposed to AuNPs, highlighting its potential role on the elimination of these NPs.


Assuntos
Ouro/toxicidade , Fígado/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Proteoma/metabolismo , Dourada/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Ácido Cítrico/química , Fígado/metabolismo , Redes e Vias Metabólicas/efeitos dos fármacos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Povidona/química , Proteômica , Propriedades de Superfície
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA