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1.
Chemosphere ; 254: 126827, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957271

RESUMO

Herein, ultrasonication (US)-assisted novel nanomaterial Ti3C2Tx MXene was utilized as a selective adsorbent for treatment of synthetic dyes in model wastewater. Two types of US frequencies, 28 and 580 kHz, were applied to disperse MXene to evaluate the feasibility of US-assisted MXene for wastewater treatment. The physico-chemical properties of MXene after US were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and zeta potential. According to FTIR and XPS, 28 kHz US-assisted MXene had a greater amount of oxygenated functional groups and dispersion compared to 580 kHz US-assisted and pristine MXene. Subsequently, US-assisted MXene was utilized as an adsorbent for the removal of positively charged methylene blue (MB) and negatively charged methyl orange. Both 28 and 580 kHz US-assisted MXene showed better adsorption performance for only MB compared to stirring-assisted MXene based on kinetics, isotherms, and several water chemistry factors including solution pH, temperature, ionic strength, and humic acid. Advantages of US-assisted MXene for water treatment are its fast kinetics at low dose and high selectivity for positively charged target compounds (i.e., MB). The main adsorption mechanism between MXene and MB was electrostatic interaction (attraction); however, physical properties (i.e., aggregation kinetics and hydrodynamic diameter), measured via dynamic light scattering, were also found to be critical factors in controlling the adsorption performance of the system. Lastly, US-assisted MXene exhibited a high regeneration property, based on 4th adsorption-desorption cycles.


Assuntos
Corantes/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Compostos Azo , Corantes/química , Difusão Dinâmica da Luz , Cinética , Azul de Metileno/química , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio/análise , Águas Residuárias/química
2.
Medicine (Baltimore) ; 99(31): e21494, 2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32756182

RESUMO

To evaluate real dynamic assessment of tear film optical quality for monitoring and prevention of dry eye.Right eyes of 62 normal and 39 dry eye subjects were included. Dynamic measurement of objective scatter index (OSI) was performed by using the Optical Quality Analysis System II (OQAS II), correlation coefficient between OSI and time (CCOT) was calculated. According to whether the CCOT was significantly ascending, normal and dry eye groups were further subdivided for comparison. By using Scheimpflug-Placido topographer, non-invasive tear break-up time (NITBUT) was recorded, and a 2-dimensional precorneal tear film map was reconstructed and divided into central, middle, and peripheral corneal zones, distribution of tear break-up spots in the 3 corneal zones were analyzed.The numbers of tear break-up spots were higher in all the 3 corneal zones of the dry eye subjects (P < .01), when compared with the normal subjects. The Dry Eye subjects with ascending CCOT had the shortest NITBUT (P < .001-.034) and the most tear break-up spots over the whole cornea (P < .001-.044). Between the dry eye subjects with non-ascending CCOT and those with ascending CCOT, difference of tear break-up spots was found significant only in the peripheral corneal zone (P < .01).Non-ascending and ascending CCOT of dry eye patients reflect different stability of tear film. Real dynamic assessment of tear film optical quality is potential for monitoring and early prevention of dry eye.


Assuntos
Síndromes do Olho Seco/diagnóstico por imagem , Difusão Dinâmica da Luz/métodos , Lágrimas/diagnóstico por imagem , Adulto , Estudos de Casos e Controles , Córnea/diagnóstico por imagem , Síndromes do Olho Seco/prevenção & controle , Feminino , Humanos , Masculino , Adulto Jovem
3.
Nat Commun ; 11(1): 4121, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32807782

RESUMO

Vasoactive intestinal polypeptide receptor (VIP1R) is a widely expressed class B G protein-coupled receptor and a drug target for the treatment of neuronal, metabolic, and inflammatory diseases. However, our understanding of its mechanism of action and the potential of drug discovery targeting this receptor is limited by the lack of structural information of VIP1R. Here we report a cryo-electron microscopy structure of human VIP1R bound to PACAP27 and Gs heterotrimer, whose complex assembly is stabilized by a NanoBiT tethering strategy. Comparison with other class B GPCR structures reveals that PACAP27 engages VIP1R with its N-terminus inserting into the ligand binding pocket at the transmembrane bundle of the receptor, which subsequently couples to the G protein in a receptor-specific manner. This structure has provided insights into the molecular basis of PACAP27 binding and VIP receptor activation. The methodology of the NanoBiT tethering may help to provide structural information of unstable complexes.


Assuntos
Microscopia Crioeletrônica/métodos , Proteínas de Ligação ao GTP/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Receptores Tipo I de Polipeptídeo Intestinal Vasoativo/metabolismo , Difusão Dinâmica da Luz , Humanos , Microscopia Eletrônica , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo
4.
Int J Nanomedicine ; 15: 5459-5471, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801700

RESUMO

Purpose: Indocyanine green (ICG), a near infrared (NIR) dye clinically approved in medical diagnostics, possesses great heat conversion efficiency, which renders itself as an effective photosensitizer for photothermal therapy (PTT) of cancer. However, there remain bottleneck challenges for use in PTT, which are the poor photo and plasma stability of ICG. To address these problems, in this research, ICG-loaded silver nanoparticles were prepared and evaluated for the applicability as an effective agent for photothermal cancer therapy. Methods and Results: PEGylated bovine serum albumin (BSA)-coated silver core/shell nanoparticles were synthesized with a high loading of ICG ("PEG-BSA-AgNP/ICG"). Physical characterization was carried out using size analyzer, transmission electron microscopy, and Fourier transform infrared spectrophotometry to identify successful preparation and size stability. ICG-loading content and the photothermal conversion efficiency of the particles were confirmed with inductively coupled plasma mass spectrometry and laser instruments. In vitro studies showed that the PEG-BSA-AgNP/ICG could provide great photostability for ICG, and their applicability for PTT was verified from the cellular study results. Furthermore, when the PEG-BSA-AgNP/ICG were tested in vivo, study results exhibited that ICG could stably remain in the blood circulation for a markedly long period (plasma half-life: 112 min), and about 1.7% ID/g tissue could be accumulated in the tumor tissue at 4 h post-injection. Such nanoparticle accumulation in the tumor enabled tumor surface temperature to be risen to 50°C (required for photo-ablation) by laser irradiation and led to successful inhibition of tumor growth in the B16F10 s.c. syngeneic nude mice model, with minimal systemic toxicity. Conclusion: Our findings demonstrated that PEG-BSA-AgNPs could serve as effective carriers for delivering ICG to the tumor tissue with great stability and safety.


Assuntos
Antineoplásicos/farmacologia , Nanopartículas Metálicas/química , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/química , Animais , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Sistemas de Liberação de Medicamentos/métodos , Estabilidade de Medicamentos , Difusão Dinâmica da Luz , Meia-Vida , Humanos , Verde de Indocianina/química , Verde de Indocianina/farmacocinética , Melanoma Experimental/tratamento farmacológico , Camundongos Endogâmicos ICR , Camundongos Nus , Microscopia Eletrônica de Transmissão , Polietilenoglicóis/química , Soroalbumina Bovina/química , Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier
5.
Int J Nanomedicine ; 15: 5517-5526, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801703

RESUMO

Introduction: Hypertension is a major health problem worldwide and is typically treated using oral drugs. However, the frequency of oral administration may result in poor patient compliance, and reduced bioavailability owing to the first-pass effect can also prove problematic. Methods: In this study, we developed a new transdermal-drug-delivery system (TDDS) for the treatment of hypertension using atenolol (ATE) based on poly(acrylic acid) (PAA)-decorated three-dimensional (3D) flower-like MoS2 nanoparticles (PAA-MoS2 NPs) that respond to NIR laser irradiation. The PAA-modified MoS2 NPs were synthesized and characterized using attenuated total reflection Fourier-transform infrared spectroscopy, X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and the sedimentation equilibrium method. The drug-loading efficiency and photothermal conversion effect were also explored. Results: The results showed that the colloidally stable PAA-MoS2 NPs exhibited a high drug-loading capacity of 54.99% and high photothermal conversion ability. Further, the capacity of the PAA-MoS2 NPs for controlled release was explored using in vitro drug-release and skin-penetration studies. The drug-release percentage was 44.72 ± 1.04%, and skin penetration was enhanced by a factor of 1.85 in the laser-stimulated group. Sustained and controlled release by the developed TDDS were observed with laser stimulation. Moreover, in vivo erythema index analysis verified that the PAA-MoS2 NPs did not cause skin irritation. Discussion: Our findings demonstrate that PAA-MoS2 NPs can be used as a new carrier for transdermal drug delivery for the first time.


Assuntos
Anti-Hipertensivos/administração & dosagem , Atenolol/administração & dosagem , Dissulfetos/química , Sistemas de Liberação de Medicamentos/métodos , Molibdênio/química , Nanopartículas/administração & dosagem , Resinas Acrílicas/química , Administração Cutânea , Animais , Anti-Hipertensivos/farmacocinética , Atenolol/efeitos adversos , Atenolol/farmacocinética , Sistemas de Liberação de Medicamentos/efeitos adversos , Liberação Controlada de Fármacos , Difusão Dinâmica da Luz , Eritema/induzido quimicamente , Humanos , Lasers , Masculino , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Coelhos , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
6.
Int J Nanomedicine ; 15: 4021-4047, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606662

RESUMO

Purpose: Periodontitis is a chronic inflammatory disease associated with microbial accumulation. The purpose of this study was to reuse the agricultural waste to produce cellulose nanofibers (CNF) and further modification of the CNF with κ-carrageenan oligosaccharides (CO) for drug delivery. In addition, this study is focused on the antimicrobial activity of surfactin-loaded CO-CNF towards periodontal pathogens. Materials and Methods: A chemo-mechanical method was used to extract the CNF and the modification was done by using CO. The studies were further proceeded by adding different quantities of surfactin [50 mg (50 SNPs), 100 mg (100 SNPs), 200 mg (200 SNPs)] into the carrier (CO-CNF). The obtained materials were characterized, and the antimicrobial activity of surfactin-loaded CO-CNF was evaluated. Results: The obtained average size of CNF and CO-CNF after ultrasonication was 263 nm and 330 nm, respectively. Microscopic studies suggested that the CNF has a short diameter with long length and CO became cross-linked to form as beads within the CNF network. The addition of CO improved the degradation temperature, crystallinity, and swelling property of CNF. The material has a controlled drug release, and the entrapment efficiency and loading capacity of the drug were 53.15 ± 2.36% and 36.72 ± 1.24%, respectively. It has antioxidant activity and inhibited the growth of periodontal pathogens such as Streptococcus mutans and Porphyromonas gingivalis by preventing the biofilm formation, reducing the metabolic activity, and promoting the oxidative stress. Conclusion: The study showed the successful extraction of CNF and modification with CO improved the physical parameters of the CNF. In addition, surfactin-loaded CO-CNF has potential antimicrobial activity against periodontal pathogens. The obtained biomaterial is economically valuable and has great potential for biomedical applications.


Assuntos
Carragenina/química , Celulose/química , Lipopeptídeos/química , Nanofibras/química , Peptídeos Cíclicos/química , Periodonto/microbiologia , Animais , Bactérias/metabolismo , Compostos de Bifenilo/química , Sobrevivência Celular , Difusão Dinâmica da Luz , Depuradores de Radicais Livres/química , Malondialdeído/metabolismo , Camundongos , Testes de Sensibilidade Microbiana , Nanofibras/ultraestrutura , Oligossacarídeos/química , Picratos/química , Células RAW 264.7 , Soja/química , Espectroscopia de Infravermelho com Transformada de Fourier
7.
J Chromatogr A ; 1625: 461282, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709333

RESUMO

In recent years, core-shell silica particles (CSSPs) have been increasingly used for highly efficient separation at fast flow rates and relatively low back pressures in high-performance liquid chromatography (HPLC). However, material synthesis techniques for producing CSSPs economically in batch processes remain elusive. In this report, a practical and straightforward method for the preparation of CSSPs is presented. By refluxing freshly prepared nonporous silica particles in ammonia-water solution in the presence of poly(diallyldimethylammonium chloride) at 70-100 °C, CSSPs with shell thicknesses of up to 300 nm and pore sizes from 8 to 25 nm were easily prepared. The effects of the synthetic conditions on the shell thickness, surface area, and pore size were investigated in detail, and the method reproducibility was evaluated in scale-up experiments. A mechanism of CSSP formation is also proposed. The CSSPs were characterized via scanning electron microscopy, transmission electron microscopy, laser particle size (dynamic light scattering) analysis, and nitrogen adsorption and desorption experiments. The synthesized 3.4-µm CSSPs were functionalized with dimethyloctadecylchlorosilane and used as an HPLC packing material, exhibiting excellent separation performance for both small molecules and large biomolecules. In summary, we report the simplest method developed thus far for the preparation of monodisperse core-shell silica particles suitable for HPLC column packing.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Sílica Gel/química , Adsorção , Amônia/análise , Difusão Dinâmica da Luz , Microesferas , Peso Molecular , Nanopartículas/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Polietilenos/química , Porosidade , Compostos de Amônio Quaternário/química , Reprodutibilidade dos Testes , Temperatura , Fatores de Tempo
8.
J Chromatogr A ; 1624: 461260, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540085

RESUMO

Complexation between poly(vinyl alcohol) (PVA) and borax in aqueous solution yields a dynamic polyelectrolyte. Study of chain conformation of such a polyelectrolyte is challenging due to the difficulty in separating different macromolecular species. In this study, we investigated conformation of dilute PVA chains complexed with borax in a wide concentration range between 0.02 and 78.6 mM using asymmetrical flow field-flow fractionation (AF4). We find that elution of the complexes is strongly influenced by the borax concentration owing to (1) the charged complex is repelled electrostatically by the charged bottom membrane of the AF4 channel, and (2) the Debye screening length reduces with increasing a charge density. The chain conformation of PVA-borax complexes depends on both polymer molar mass and borax concentration. At low borax concentrations of 0.02~0.5 mM, a transition from random coil to rod-like conformation is observed with increasing the chain size. At borax concentrations of 1 mM and higher, all chains become random coil owing to a reduced screening length of the electrostatic repulsion.


Assuntos
Boratos/química , Fracionamento por Campo e Fluxo/métodos , Conformação Molecular , Álcool de Polivinil/química , Difusão Dinâmica da Luz , Etanol/química , Peso Molecular , Eletricidade Estática , Água
9.
Int J Nanomedicine ; 15: 3791-3801, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547028

RESUMO

Purpose: Paclitaxel is a generic drug produced based on Taxol which is an extract of Taxus tree, well known for its anticancer and antibacterial effects. This study was aimed at building up an agent with the antibacterial and anticancer benefits of both the silver ions and Taxol, together with less cytotoxic effects. Materials and Methods: Colloidal silver nanoparticles (AgNPs) were synthesized by reducing aqueous AgNO3 with aqueous Taxus leaf extract at nonphotomediated conditions, without any catalyst, template or surfactant. The AgNP production was confirmed by ultraviolet-visible (UV-VIS) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared (FTI) spectroscopy. The MTT assay for human breast cancer cells as well as the DAPI fluorescent staining microscopy tested the biocompatibility and anticancer effects of AgNPs, silver nitrate, and Taxol. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques were performed to determine the shape and size of the nanoparticles. MTT assay showed the best inhibitory concentration of AgNPs on cancer cells. The antibacterial activity of the three case study materials was tested for gram-positive (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) using well diffusion test. Results: This work proposes more anticancer effects for AgNP made by Taxus brevifolia extract, comparing Taxol solution. IC50 was observed as 3.1 mM for Taxol while 1.5 mM for new AgNP. Moreover, Taxus showed no antibacterial effects while the new AgNP showed a dose-dependent biocompatibility along with slightly more antibacterial effects (MIC: 1.6 and 6.6mM for gram-positive and -negative bacteria, respectively) comparing with silver nitrate solution (MIC: 1.5 and 6.2 mM for gram-positive and -negative bacteria, respectively). Conclusion: The production of herbal-mediated silver nanoparticles may be an efficient substitution for the silver nitrate-based medicines with less side effects.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Química Verde/métodos , Nanopartículas Metálicas/uso terapêutico , Prata/farmacologia , Taxus/química , Difusão Dinâmica da Luz , Escherichia coli/efeitos dos fármacos , Humanos , Células MCF-7 , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Extratos Vegetais/química , Staphylococcus aureus/efeitos dos fármacos
10.
Life Sci ; 256: 117961, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32534039

RESUMO

The study focuses on whether antigenic proteins encapsulated in biopolymeric nanoparticles can augment protective efficacy. Chitosan nanoparticles (ChN) were prepared by ionic gelation method and Culture Filtrate Proteins (CFP) - CFP-10 and CFP-21 of Mycobacterium tuberculosis (Mtb) were encapsulated in ChN. The binding efficiency of nanoparticles with CFP-10 and CFP-21 proteins was confirmed by UV-Spectrophotometer. The efficacy of nanoparticles-encapsulated antigenic proteins administered intraperitoneal against Mtb aerosol infection was evaluated in Balb/c mice. Protection study was done by bacterial counts [CFU]. CFP-10 and CFP-21 proteins primed cells demonstrated a Th1 bias T cell response in an ex vivo assay. ChN-CFP10 and ChN-CFP21 nanoparticles have both protective and therapeutic potential against Mtb. In the group of mice immunized with CHN-CFP-10 the number of colonies reduced significantly from day 15 to day 60. ChN-CFP-21 showed maximum protection in ChN-CFP-21 immunized mice. ChN-CFP-10 and ChN-CFP-21 clearly showed enhanced protection against Mtb.


Assuntos
Antígenos de Bactérias/farmacologia , Proteínas de Bactérias/farmacologia , Quitosana/química , Mycobacterium tuberculosis/metabolismo , Nanopartículas/química , Substâncias Protetoras/farmacologia , Animais , Difusão Dinâmica da Luz , Feminino , Glutationa Transferase/metabolismo , Camundongos Endogâmicos BALB C , Nanopartículas/ultraestrutura , Óxido Nítrico/metabolismo , Estresse Oxidativo , Tamanho da Partícula , Eletricidade Estática
11.
Proc Natl Acad Sci U S A ; 117(22): 11875-11877, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: covidwho-260636

RESUMO

Speech droplets generated by asymptomatic carriers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are increasingly considered to be a likely mode of disease transmission. Highly sensitive laser light scattering observations have revealed that loud speech can emit thousands of oral fluid droplets per second. In a closed, stagnant air environment, they disappear from the window of view with time constants in the range of 8 to 14 min, which corresponds to droplet nuclei of ca. 4 µm diameter, or 12- to 21-µm droplets prior to dehydration. These observations confirm that there is a substantial probability that normal speaking causes airborne virus transmission in confined environments.


Assuntos
Microbiologia do Ar , Betacoronavirus/fisiologia , Infecções por Coronavirus/transmissão , Pneumonia Viral/transmissão , Saliva/virologia , Difusão Dinâmica da Luz , Fômites/virologia , Humanos , Pandemias , Tamanho da Partícula , Vírus da SARS , Saliva/química , Fala , Carga Viral
12.
Int J Nanomedicine ; 15: 2617-2631, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368044

RESUMO

Introduction: As widely used chemotherapeutic agents, platinum compounds have several therapeutic challenges, such as drug resistance and adverse effects. Theranostic systems, macromolecular or colloidal therapeutics with companion diagnostics, not only address controlled drug delivery but also enable real-time monitoring of tumor sites. Methods: Synthesis of magnetic mesoporous silica nanoparticles (MMSNs) was performed for dual magnetic resonance imaging and drug delivery. MMSN surfaces were modified by imidazoline groups (MMSN-Imi) for cisplatin (Cis-Pt) conjugation via free N-termini to achieve well-controlled drug-release kinetics. Cis-Pt adsorption isotherms and drug-release profile at pH 5 and 7.4 were investigated using inductively coupled plasma atomic emission spectroscopy. Results: MMSN-Imi showed a specific surface area of 517.6 m2 g-1, mean pore diameter of 3.26 nm, and saturated magnetization of 53.63 emu/g. A relatively high r2/r1 relaxivity value was obtained for MMSN-Imi. The nanoparticles provided high Cis-Pt loading with acceptable loading capacity (~30% w:w). Sustained release of Cis-Pt under acidic conditions led to specific inhibitory effects on the growth of human epithelial ovarian carcinoma cells, determined using MTT assays. Dual acridine orange-propidium iodide staining was investigated, confirming induction of apoptosis and necrotic cell death. Conclusion: MMSN-Imi exhibited potential for applications in cancer chemotherapy and combined imaging.


Assuntos
Sistemas de Liberação de Medicamentos , Imidazolinas/química , Nanopartículas de Magnetita/química , Platina/administração & dosagem , Dióxido de Silício/química , Nanomedicina Teranóstica , Adsorção , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacologia , Morte Celular , Linhagem Celular Tumoral , Cisplatino/administração & dosagem , Cisplatino/farmacologia , Liberação Controlada de Fármacos , Difusão Dinâmica da Luz , Hemólise , Humanos , Cinética , Imagem por Ressonância Magnética , Nanopartículas de Magnetita/ultraestrutura , Nitrogênio/química , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Temperatura , Difração de Raios X
13.
Nat Commun ; 11(1): 2331, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393780

RESUMO

Extracellular vesicles have an important function in cellular communication. Here, we show that human and mouse monocytes release TGF-ß1-transporting vesicles in response to the pathogenic fungus Candida albicans. Soluble ß-glucan from C. albicans binds to complement receptor 3 (CR3, also known as CD11b/CD18) on monocytes and induces the release of TGF-ß1-transporting vesicles. CR3-dependence is demonstrated using CR3-deficient (CD11b knockout) monocytes generated by CRISPR-CAS9 genome editing and isolated from CR3-deficient (CD11b knockout) mice. These vesicles reduce the pro-inflammatory response in human M1-macrophages as well as in whole blood. Binding of the vesicle-transported TGF-ß1 to the TGF-ß receptor inhibits IL1B transcription via the SMAD7 pathway in whole blood and induces TGFB1 transcription in endothelial cells, which is resolved upon TGF-ß1 inhibition. Notably, human complement-opsonized apoptotic bodies induce production of similar TGF-ß1-transporting vesicles in monocytes, suggesting that the early immune response might be suppressed through this CR3-dependent anti-inflammatory vesicle pathway.


Assuntos
Imunomodulação , Antígeno de Macrófago 1/metabolismo , Monócitos/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Vesículas Transportadoras/metabolismo , Animais , Apoptose , Candida albicans/metabolismo , Candida albicans/ultraestrutura , Regulação para Baixo , Difusão Dinâmica da Luz , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Inflamação/patologia , Interleucina-6/genética , Interleucina-6/metabolismo , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Modelos Biológicos , Monócitos/microbiologia , Monócitos/ultraestrutura , Transporte Proteico , Solubilidade , Transcrição Genética , Regulação para Cima , beta-Glucanas/metabolismo
14.
Food Chem ; 327: 127000, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454284

RESUMO

Iron oxides used as food colorants are listed in the European Union with the number E172. However, there are no specifications concerning the fraction of nanoparticles in these pigments. Here, seven E172 products were thoroughly characterized. Samples of all colors were analyzed with a broad spectrum of methods to assess their physico-chemical properties. Small-Angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), zeta-potential, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), X-ray diffraction (XRD), Brunauer-Emmett-Teller analysis (BET), Asymmetric Flow Field-Flow Fractionation (AF4) and in vitro cell viability measurements were used. Nanoparticles were detected in all E172 samples by TEM or SAXS measurements. Quantitative results from both methods were comparable. Five pigments were evaluated by TEM, of which four had a size median below 100 nm, while SAXS showed a size median below 100 nm for six evaluated pigments. Therefore, consumers may be exposed to iron oxide nanoparticles through the consumption of food pigments.


Assuntos
Compostos Férricos/química , Corantes de Alimentos/química , Difusão Dinâmica da Luz , Fracionamento por Campo e Fluxo/métodos , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Tamanho da Partícula , Espalhamento a Baixo Ângulo , Difração de Raios X
15.
Proc Natl Acad Sci U S A ; 117(22): 11875-11877, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32404416

RESUMO

Speech droplets generated by asymptomatic carriers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are increasingly considered to be a likely mode of disease transmission. Highly sensitive laser light scattering observations have revealed that loud speech can emit thousands of oral fluid droplets per second. In a closed, stagnant air environment, they disappear from the window of view with time constants in the range of 8 to 14 min, which corresponds to droplet nuclei of ca. 4 µm diameter, or 12- to 21-µm droplets prior to dehydration. These observations confirm that there is a substantial probability that normal speaking causes airborne virus transmission in confined environments.


Assuntos
Microbiologia do Ar , Betacoronavirus/fisiologia , Infecções por Coronavirus/transmissão , Pneumonia Viral/transmissão , Saliva/virologia , Difusão Dinâmica da Luz , Fômites/virologia , Humanos , Pandemias , Tamanho da Partícula , Vírus da SARS , Saliva/química , Fala , Carga Viral
16.
PLoS One ; 15(4): e0221180, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32320392

RESUMO

At the molecular level, the circadian clock is regulated by a time delayed transcriptional-translational feedback loop in which the core proteins interact with each other rhythmically to drive daily biological rhythms. The C-terminal domain of a key clock protein PER2 (PER2c) plays a critically important role in the loop, not only for its interaction with the binding partner CRY proteins but also for the CRY/PER complex's translocation from the cytosol to the nucleus. Previous circular dichroism (CD) spectroscopic studies have shown that mouse PER2c (mPER2c) is less structured in solution by itself but folded into stable secondary structures upon interaction with mouse CRYs. To understand the stability and folding of human PER2c (hPER2c), we expressed and purified hPER2c. Three oligomerization forms of recombinant hPER2c were identified and thoroughly characterized through a combination of biochemical and biophysical techniques. Different to mPER2c, both thermal unfolding DLS and CD analyses suggested that all forms of hPER2c have very stable secondary structures in solution by themselves with melting temperatures higher than the physiological body temperature, indicating that hPER2c does not require CRY to fold. Furthermore, we examined the effects of EDTA, salt concentration, and a reducing agent on hPER2c folding and oligomerization. The ability of hPER2c forming oligomers reflects the potential role of hPER2c in the assembly of circadian rhythm core protein complexes.


Assuntos
Proteínas Circadianas Period/química , Sequência de Aminoácidos , Dicroísmo Circular , Difusão Dinâmica da Luz , Humanos , Modelos Moleculares , Domínios Proteicos , Dobramento de Proteína , Estabilidade Proteica , Estrutura Secundária de Proteína , Temperatura
17.
Int J Nanomedicine ; 15: 1837-1851, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32256063

RESUMO

Introduction: Gold nanorods are highly reactive, have a large surface-to-volume ratio, and can be functionalized with biomolecules. Gold nanorods can absorb infrared electromagnetic radiation, which is subsequently dispersed as local heat. Gold nanoparticles can be used as powerful tools for the diagnosis and therapy of different diseases. To improve the biological barrier permeation of nanoparticles with low cytotoxicity, in this study, we conjugated gold nanorods with cell-penetrating peptides (oligoarginines) and with the amphipathic peptide CLPFFD. Methods: We studied the interaction of the functionalized gold nanorods with biological membrane models (liposomes) by dynamic light scattering, transmission electron microscopy and the Langmuir balance. Furthermore, we evaluated the effects on cell viability and permeability with an MTS assay and TEM. Results and Discussion: The interaction study by DLS, the Langmuir balance and cryo-TEM support that GNR-Arg7CLPFFD enhances the interactions between GNRs and biological membranes. In addition, cells treated with GNR-Arg7CLPFFD internalized 80% more nanoparticles than cells treated with GNR alone and did not induce cell damage. Conclusion: Our results indicate that incorporation of an amphipathic sequence into oligoarginines for the functionalization of gold nanorods enhances biological membrane nanoparticle interactions and nanoparticle cell permeability with respect to nanorods functionalized with oligoarginine. Overall, functionalized gold nanorods with amphipathic arginine rich peptides might be candidates for improving drug delivery by facilitating biological barrier permeation.


Assuntos
Peptídeos Penetradores de Células/química , Lipossomos/farmacocinética , Nanotubos/química , Arginina/química , Linhagem Celular Tumoral , Sobrevivência Celular , Peptídeos Penetradores de Células/farmacocinética , Sistemas de Liberação de Medicamentos , Difusão Dinâmica da Luz , Ouro/química , Humanos , Lipossomos/química , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Peptídeos/química
18.
Environ Sci Pollut Res Int ; 27(17): 22120-22126, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32304044

RESUMO

This study was performed to explore acute toxicity of biologically synthesized gold nanoparticles (AuNPs) to a model organism Daphnia magna. Hence, using aqueous extract of marine macroalga Saccharina japonica, two AuNPs including SJ-AuNPs-72 (72.6 ± 43.8 nm) and SJ-AuNPs-10 (10.8 ± 2.8 nm) were synthesized. These AuNPs were characterized by different techniques such as UV-Vis spectrophotometry, transmission electron microscopy (TEM), dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDX). The 48-h LC50 values of SJ-AuNPs-72 and SJ-AuNPs-10 to D. magna were 1.57 ± 0.07 and 2.69 ± 0.12 mg/L, respectively, showing greater toxicity of SJ-AuNPs-72. After exposure of daphnids to treatments, AuNPs were accumulated in gut tract, and lipid droplets under the Daphnia carapace were also observed. Whereas studies on toxicity of biosynthesized AuNPs are still scarce, the achievements of this work are helpful for understanding the toxicity of biosynthesized AuNPs to crustacean D. magna.


Assuntos
Nanopartículas Metálicas , Alga Marinha , Animais , Daphnia , Difusão Dinâmica da Luz , Ouro , Extratos Vegetais , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Int J Nanomedicine ; 15: 1823-1835, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32214814

RESUMO

Background: Biodegradation of toxic organic dye using nanomaterial-based microbial biocatalyst is an ecofriendly and promising technique. Materials and Methods: Here, we have investigated the novel properties of functionalized Au-Ag bimetallic nanoparticles using extremophilic Deinococcus radiodurans proteins (Drp-Au-AgNPs) and their degradation efficiency on the toxic triphenylmethane dye malachite green (MG). Results and Discussion: The prepared Drp-Au-AgNPs with an average particle size of 149.8 nm were capped by proteins through groups including hydroxyl and amide. Drp-Au-AgNPs demonstrated greater degradation ability (83.68%) of MG than D. radiodurans cells and monometallic AuNPs. The major degradation product was identified as 4-(dimethylamino) benzophenone, which is less toxic than MG. The degradation of MG was mainly attributed to the capping proteins on Drp-Au-AgNPs. The bimetallic NPs could be reused and maintained MG degradation ability (>64%) after 2 cycles. Conclusion: These results suggest that the easily prepared Drp-Au-AgNPs have potential applications as novel nanomedicine for MG detoxification, and nanomaterial for biotreatment of a toxic polyphenyl dye-containing wastewater.


Assuntos
Proteínas de Bactérias/metabolismo , Deinococcus/química , Nanopartículas Metálicas/química , Corantes de Rosanilina/metabolismo , Proteínas de Bactérias/química , Corantes/química , Corantes/metabolismo , Difusão Dinâmica da Luz , Cromatografia Gasosa-Espectrometria de Massas , Ouro/química , Ouro/metabolismo , Tamanho da Partícula , Corantes de Rosanilina/química , Prata/química , Prata/metabolismo , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
20.
Food Chem ; 318: 126479, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32135423

RESUMO

In this study, we prepared waxy maize starch nanocrystals (SNCs) for the first time using dry-heated oxalic acid hydrolysis with or without ultrasonic treatment. The dry-heating treatment was subjected to oxalic acid hydrolysis to produce SNCs with a high yield of 89.6%. Dynamic light scattering showed that the size of the obtained SNCs was 46.58-197.15 nm, and the polydispersion index was 0.28-0.52. Atomic force microscopy investigation found that the SNCs had a major axis of about 211.5 nm and a height of about 9.4 nm. The thermogravimetric analysis revealed that the SNCs' thermal stability slightly improved compared with that of native starch. X-ray diffraction indicated that the produced SNCs preserved the A-type crystal form of native starch, with the relative crystallinities of 29.52%-42.44%. The newly fabricated SNCs have potential applications in agriculture, cosmetics, and advanced materials.


Assuntos
Nanopartículas/química , Amido/química , Zea mays/química , Difusão Dinâmica da Luz , Hidrólise , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Ácido Oxálico/química , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Ultrassom , Difração de Raios X
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