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1.
Nat Commun ; 11(1): 4535, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913217

RESUMO

The current understanding of the biological identity that nanoparticles may acquire in a given biological milieu is mostly inferred from the hard component of the protein corona (HC). The composition of soft corona (SC) proteins and their biological relevance have remained elusive due to the lack of analytical separation methods. Here, we identify a set of specific corona proteins with weak interactions at silica and polystyrene nanoparticles by using an in situ click-chemistry reaction. We show that these SC proteins are present also in the HC, but are specifically enriched after the capture, suggesting that the main distinction between HC and SC is the differential binding strength of the same proteins. Interestingly, the weakly interacting proteins are revealed as modulators of nanoparticle-cell association mainly through their dynamic nature. We therefore highlight that weak interactions of proteins at nanoparticles should be considered when evaluating nano-bio interfaces.


Assuntos
Nanopartículas/química , Coroa de Proteína/química , Química Click , Reagentes para Ligações Cruzadas/química , Células Endoteliais , Humanos , Poliestirenos/química , Ligação Proteica , Coroa de Proteína/análise , Dióxido de Silício/química , Células THP-1
2.
Int J Nanomedicine ; 15: 4779-4791, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32753866

RESUMO

Background: Considering the timeline required for the development of novel antimicrobial drugs, increased attention should be given to repurposing old drugs and improving antimicrobial efficacy, particularly for chronic infections associated with biofilms. Methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are common causes of biofilm-associated infections but produce different biofilm matrices. MSSA biofilm cells are typically embedded in an extracellular polysaccharide matrix, whereas MRSA biofilms comprise predominantly of surface proteins and extracellular DNA (eDNA). Nanoparticles (NPs) have the potential to enhance the delivery of antimicrobial agents into biofilms. However, the mechanisms which influence the interactions between NPs and the biofilm matrix are not yet fully understood. Methods: To investigate the influence of NPs surface chemistry on vancomycin (VAN) encapsulation and NP entrapment in MRSA and MSSA biofilms, mesoporous silica nanoparticles (MSNs) with different surface functionalization (bare-B, amine-D, carboxyl-C, aromatic-A) were synthesised using an adapted Stöber method. The antibacterial efficacy of VAN-loaded MSNs was assessed against MRSA and MSSA biofilms. Results: The two negatively charged MSNs (MSN-B and MSN-C) showed a higher VAN loading in comparison to the positively charged MSNs (MSN-D and MSN-A). Cellular binding with MSN suspensions (0.25 mg mL-1) correlated with the reduced viability of both MSSA and MRSA biofilm cells. This allowed the administration of low MSNs concentrations while maintaining a high local concentration of the antibiotic surrounding the bacterial cells. Conclusion: Our data suggest that by tailoring the surface functionalization of MSNs, enhanced bacterial cell targeting can be achieved, leading to a novel treatment strategy for biofilm infections.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes , Staphylococcus aureus Resistente à Meticilina/fisiologia , Nanopartículas/química , Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/ultraestrutura , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Espectroscopia de Prótons por Ressonância Magnética , Dióxido de Silício/química , Vancomicina/farmacologia
3.
Nat Commun ; 11(1): 4249, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843618

RESUMO

Aberrant cell cycle machinery and loss of the CDKN2A tumor suppressor locus make CDK4/6 a potential target in pancreatic ductal adenocarcinoma (PDAC). However, a vast majority of PDAC cases do not harbor a durable response to monotherapy of CDK4/6 inhibitor. Utilizing remote loading to co-encapsulate CDK4/6 inhibitor palbociclib (PAL) and an autophagy inhibitor hydroxychloroquine (HCQ), we demonstrate a ratiometrically designed mesoporous silica nanoformulation with synergistic efficacy in subcutaneous and orthotopic PDAC mouse models. The synergism is attributed to the effective intratumoral buildup of PAL/HCQ, which otherwise exhibit distinctly different circulatory and biodistribution profile. PAL/HCQ co-delivery nanoparticles lead to the most effective shrinkage of PDAC compared to various controls, including free drug mixture. Immunohistochemistry reveals that PAL/HCQ co-delivery nanoparticles trigger anti-apoptotic pathway after repetitive intravenous administrations in mice. When combined with a Bcl inhibitor, the performance of co-delivery nanoparticles is further improved, leading to a long-lasting anti-PDAC effect in vivo.


Assuntos
Autofagia/efeitos dos fármacos , Carcinoma Ductal Pancreático/tratamento farmacológico , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Sistemas de Liberação de Medicamentos , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Modelos Animais de Doenças , Sinergismo Farmacológico , Humanos , Hidroxicloroquina/administração & dosagem , Hidroxicloroquina/química , Hidroxicloroquina/farmacologia , Camundongos , Nanopartículas/administração & dosagem , Nanopartículas/química , Piperazinas/administração & dosagem , Piperazinas/química , Piperazinas/farmacologia , Piridinas/administração & dosagem , Piridinas/química , Piridinas/farmacologia , Dióxido de Silício/administração & dosagem , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Resultado do Tratamento
4.
J Chromatogr A ; 1627: 461372, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823089

RESUMO

This paper demonstrated the non-validity of Schultz et al. method by proving that the surface areas of n-alkanes and polar molecules strongly depend of the temperature. Consequently, the results of surface properties obtained by this method are inaccurate. Inverse gas chromatography (IGC) at infinite dilution and the dynamic contact angle (DCA) technique were used on the polytetrafluoroethylene (PTFE) fibers. DCA measurements led to the determination of the surface energy γs(T) of PTFE fibers as a function of the temperature T (Relation 6). The variations of the surface areas of n-alkanes and polar molecules versus the temperature were determined by studying the same PTFE fibers by IGC at infinite dilution. We proved that the product of the surface area a(T, Cn) (in Å2) of an alkane by the dispersive component of the surface energyγsd(T)of the solid is constant at any temperature: [Formula: see text] , where b(Cn) is a constant only depending on the carbon atom number n of n-alkane Cn. An analytical relation of the surface area of n-alkanes as a function of the temperature was obtained (equation 18). Our results highlighted the failure of Dorris-Gray method that was largely used to determine γsd of solids. This method considered the surface area a-CH2- of methylene group equal to 6 Å2 and constant for any used temperature. The obtained results proved the non-validity of Dorris-Gray method and gave the expression of a-CH2- as a function of the temperature T (Equation 20) proved the non-validity of Dorris-Gray method. The calculations of the thermal expansion coefficients of the surface area a and radius R represented by the respective derivatives da/dT and dR/dT, showed their important variations as a function of the temperature. The general expression of the surface area aX(T) of polar molecules was given as a function of the temperature (Expression 48). The large effect of the temperature on surface areas and radii of molecules was highlighted, except for toluene. The surface area of toluene was proved to remain constant whatever the temperature. Our results showed, in general, non-linear variations of the radius rX(T) of polar molecules adsorbed on PTFE fibers. However, except for chloroform, dichloromethane and diethyl ether where their thermal expansion coefficient depends on the temperature, the linearity of rX(T) was verified in the temperature interval [293 K, 353 K].


Assuntos
Cromatografia Gasosa/métodos , Modelos Moleculares , Compostos Orgânicos/análise , Temperatura , Adsorção , Alcanos/análise , Politetrafluoretileno/análise , Dióxido de Silício/química , Propriedades de Superfície
5.
J Chromatogr A ; 1627: 461382, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823094

RESUMO

A method is described for the functionalization of magnetic carbon nanotubes to recognize aristolochic acid Ⅰ and Ⅱ. 3-Glycidyloxypropyltrimethoxysilane was used as a coupling agent to immobilize adenine on a solid support. The morphology and structure of adenine-coated magnetic carbon nanotubes was investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). The adsorption performance of the adenine-coated magnetic carbon nanotubes was evaluated via adsorption isotherms, the kinetics and selectivity tests. The adsorption capacity of the adenine-functionalized sorbent for aristolochic acid Ⅰ was determined to be 24.5 µg mg-1. By combining magnetic solid phase extraction with HPLC detection, a method was developed to enrich and detect aristolochic acids used in traditional Chinese medicine. A satisfactory recovery (92.7 - 97.5% for aristolochic acid Ⅰ and 92.6 - 99.4% for aristolochic acid Ⅱ) and an acceptable relative standard deviation (<4.0%) were obtained.


Assuntos
Adenina/química , Ácidos Aristolóquicos/isolamento & purificação , Fenômenos Magnéticos , Nanotubos de Carbono/química , Adsorção , Medicamentos de Ervas Chinesas/química , Compostos Férricos/síntese química , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Cinética , Nanocompostos/química , Nanotubos de Carbono/ultraestrutura , Concentração Osmolar , Reprodutibilidade dos Testes , Dióxido de Silício/síntese química , Dióxido de Silício/química , Extração em Fase Sólida , Temperatura , Difração de Raios X
6.
J Chromatogr A ; 1626: 461379, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797854

RESUMO

Ordered porous materials are attracting enormous attention due to their uniform pore structures, particularly the magnetic photonic crystal microspheres (PCMs) which not only possess unique photonic crystal structure but also can achieve separation easily based on magnet. Here, a two-phase microfluidic self-assembly synthetic system was established simply and employed for the preparation of three dimensional PCMs (3DPCMs) by using the emulsion droplet approach. One phase (dispersed phase) was an aqueous emulsion containing Fe3O4, silica (SiO2) and polystyrene (PS) nanoparticles; another phase (continuous phase) was pure silicone oil. The droplets were formed by introducing the dispersed phase into the continuous phase through a tee valve. By heating the droplets, the water would evaporate and the nanoparticles would finally assemble into solid microspheres, which could be changed into macroporous 3DPCMs after removal of the PS nanoparticles by calcination. The contents and particle sizes of Fe3O4, SiO2 and PS nanoparticles in the dispersed phase were investigated in detail and optimized to prepare macroporous magnetic 3DPCMs with high quality. The morphologies, surface crystal structure, magnetic property, particle size distribution, specific surface area and pore size of the macroporous magnetic 3DPCMs were characterized. The expected 3DPCM displayed regular and uniform photonic crystal structure, narrow particle size distribution and strong magnetic property. The macroporous magnetic 3DPCMs grafted with vomitoxin (DON)-antibodies could be applied for selective enrichment of DON in real samples.


Assuntos
Magnetismo , Microfluídica/métodos , Microesferas , Tricotecenos/análise , Anticorpos/imunologia , Cromatografia Líquida de Alta Pressão , Óxido Ferroso-Férrico/química , Contaminação de Alimentos/análise , Nanopartículas/química , Tamanho da Partícula , Poliestirenos/química , Porosidade , Dióxido de Silício/química , Espectrofotometria , Tricotecenos/imunologia
7.
J Chromatogr A ; 1627: 461423, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823118

RESUMO

A novel stationary phase co-modified with N-isopropyl acrylamide (NIPAM) and 3-aminophenylboronic acid copolymer on the silica was synthesized through atom transfer radical polymerization (ATRP) reaction for performing mixed-mode and boronate affinity chromatography. The prepared functionalized silica was characterized using Fourier transform infrared spectrometry (FT-IR), elemental analysis (EA) and thermogravimetric analysis (TGA), scanning electron micrographs (SEM) and Brunauer-Emmett-Teller (BET) measurements. The prepared column named Sil-PBA-NIPAM showed great separation performance for hydrophobic, hydrophilic, positional isomer, acidic and alkaline compounds. Besides, the mixture of cis-diol and non-cis-diol compounds was used to prove that the developed column also has potential to capture and enrich cis-diol compounds. The prepared column possesses merits of time-saving, high selectivity to cis-diol compounds and molecular-planarity selectivity compared with two commercial single-mode columns. The theoretical plates of material can reach to 57472 and the column has good hydrolysis stability and batch-to-batch reproducibility. In summary, the prepared column possesses good hydrophilicity, hydrophobicity, molecular-planarity selectivity and boronate affinity abilities for the analysis of various compounds.


Assuntos
Acrilamidas/química , Ácidos Borônicos/química , Cromatografia/métodos , Polímeros/química , Ácido Benzoico/análise , Cromatografia de Fase Reversa , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Fenóis/análise , Polimerização , Reprodutibilidade dos Testes , Dióxido de Silício/química , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
8.
Int J Nanomedicine ; 15: 5181-5202, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801685

RESUMO

Background: Combating infectious diseases caused by influenza virus is a major challenge due to its resistance to available drugs and vaccines, side effects, and cost of treatment. Nanomedicines are being developed to allow targeted delivery of drugs to attack specific cells or viruses. Materials and Methods: In this study, mesoporous silica nanoparticles (MSNs) functionalized with amino groups and loaded with natural prodrugs of shikimic acid (SH), quercetin (QR) or both were explored as a novel antiviral nanoformulations targeting the highly pathogenic avian influenza H5N1 virus. Also, the immunomodulatory effects were investigated in vitro tests and anti-inflammatory activity was determined in vivo using the acute carrageenan-induced paw edema rat model. Results: Prodrugs alone or the MSNs displayed weaker antiviral effects as evidenced by virus titers and plaque formation compared to nanoformulations. The MSNs-NH2-SH and MSNs-NH2-SH-QR2 nanoformulations displayed a strong virucidal by inactivating the H5N1 virus. They induced also strong immunomodulatory effects: they inhibited cytokines (TNF-α, IL-1ß) and nitric oxide production by approximately 50% for MSNs-NH2-SH-QR2 (containing both SH and QR). Remarkable anti-inflammatory effects were observed during in vivo tests in an acute carrageenan-induced rat model. Conclusion: Our preliminary findings show the potential of nanotechnology for the application of natural prodrug substances to produce a novel safe, effective, and affordable antiviral drug.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Antivirais/farmacologia , Virus da Influenza A Subtipo H5N1/efeitos dos fármacos , Nanopartículas/química , Pró-Fármacos/farmacologia , Animais , Anti-Inflamatórios não Esteroides/imunologia , Antivirais/imunologia , Citocinas/metabolismo , Cães , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Edema/tratamento farmacológico , Edema/metabolismo , Fatores Imunológicos/imunologia , Fatores Imunológicos/farmacologia , Células Madin Darby de Rim Canino , Masculino , Camundongos , Quercetina/imunologia , Quercetina/farmacologia , Ratos , Ácido Chiquímico/imunologia , Ácido Chiquímico/farmacologia , Dióxido de Silício/química
9.
Int J Nanomedicine ; 15: 5227-5237, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801688

RESUMO

Background: Large-scale production and application of amorphous silica nanoparticles (SiNPs) have enhanced the risk of human exposure to SiNPs. However, the toxic effects and the underlying biological mechanisms of SiNPs on Caenorhabditis elegans remain largely unclear. Purpose: This study was to investigate the genome-wide transcriptional alteration of SiNPs on C. elegans. Methods and Results: In this study, a total number of 3105 differentially expressed genes were identified in C. elegans. Among them, 1398 genes were significantly upregulated and 1707 genes were notably downregulated in C. elegans. Gene ontology analysis revealed that the significant change of gene functional categories triggered by SiNPs was focused on locomotion, determination of adult lifespan, reproduction, body morphogenesis, multicellular organism development, endoplasmic reticulum unfolded protein response, oocyte development, and nematode larval development. Meanwhile, we explored the regulated effects between microRNA and genes or signaling pathways. Pathway enrichment analysis and miRNA-gene-pathway-network displayed that 23 differential expression microRNA including cel-miR-85-3p, cel-miR-793, cel-miR-241-5p, and cel-miR-5549-5p could regulate the longevity-related pathways and inflammation signaling pathways, etc. Additionally, our data confirmed that SiNPs could disrupt the locomotion behavior and reduce the longevity by activating ins-7, daf-16, ftt-2, fat-5, and rho-1 genes in C. elegans. Conclusion: Our study showed that SiNPs induced the change of the whole transcriptome in C. elegans, and triggered negative effects on longevity, development, reproduction, and body morphogenesis. These data provide abundant clues to understand the molecular mechanisms of SiNPs in C. elegans.


Assuntos
Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Nanopartículas/toxicidade , Animais , Proteínas de Caenorhabditis elegans/genética , Redes Reguladoras de Genes/efeitos dos fármacos , Genoma Helmíntico , Humanos , Longevidade/efeitos dos fármacos , MicroRNAs/genética , Testes de Mutagenicidade/métodos , Nanopartículas/química , Reprodução/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Dióxido de Silício/química , Dióxido de Silício/toxicidade , Transcriptoma , Resposta a Proteínas não Dobradas/genética
10.
Int J Nanomedicine ; 15: 5239-5252, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801689

RESUMO

Introduction: The main pathological mechanism of restenosis after percutaneous coronary intervention (PCI) is intimal hyperplasia, which is mainly caused by proliferation and migration of vascular smooth muscle cells (VSMCs). Our previous study found that honokiol (HNK), a small-molecule polyphenol, can inhibit neointimal hyperplasia after balloon injury, but its specific mechanism is still unclear. Moreover, poor water solubility as well as low bioavailability of honokiol has limited its practical use. Methods: We used mesoporous silica nanoparticles (MSNPs) as a standard substance to encapsulate HNK and then assemble into honokiol-mesoporous silica nanoparticles, and we investigated the effect of these nanoparticles on the process of restenosis after common carotid artery injury in rats. Results: We report a promising delivery system that loads HNK into MSNPs and finally assembles it into a nanocomposite particle. These HNK-MSNPs not merely inhibited proliferation and migration of VSMCs by reducing phosphorylation of Smad3, but also showed a higher suppression of intimal thickening than the free-honokiol-treated group in a rat model of balloon injury. Conclusion: To sum up, this drug delivery system supplies a potent nano-platform for improving the biological effects of HNK and provides a promising strategy for preventing vascular restenosis.


Assuntos
Compostos de Bifenilo/farmacologia , Reestenose Coronária/tratamento farmacológico , Sistemas de Liberação de Medicamentos/métodos , Lignanas/farmacologia , Nanopartículas/química , Intervenção Coronária Percutânea/efeitos adversos , Animais , Compostos de Bifenilo/administração & dosagem , Compostos de Bifenilo/farmacocinética , Lesões das Artérias Carótidas/etiologia , Lesões das Artérias Carótidas/metabolismo , Lesões das Artérias Carótidas/patologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Reestenose Coronária/metabolismo , Modelos Animais de Doenças , Humanos , Lignanas/administração & dosagem , Lignanas/farmacocinética , Masculino , Músculo Liso Vascular/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Nanopartículas/administração & dosagem , Poloxâmero/química , Ratos Sprague-Dawley , Dióxido de Silício/química
11.
J Oleo Sci ; 69(8): 893-905, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32759550

RESUMO

In this study, lipase from Thermomyces lanuginosus (TLL) was immobilized onto the parent and organic groups modified SBA-15, and the enzymatic properties of the obtained immobilized TLL samples were investigated. 1) Activity of SBA-15-TLL at 2862.78 ± 293.24 U/g was obtained. 2) Most of the organic groups modification favored a great improvement in activity, and higher activity over 12000 U/g was observed for N-phenylaminomethyl and phenyl group modification. 3) Most of the supported TLL showed better thermostability in air while poor in phosphate buffer, with over 80% vers less than 20% of their initial activity retained after 4 h incubation at 70℃. 4) The n-dodecyl, phenyl and N-phenylaminomethyl group functionalization decreased the sensitivity of immobilized TLL in extreme pH values. 5) The n-octyl and 2-(propoxymethyl)oxirane group modification confered the supported TLL good reusability, and over 60% of their initial activity was retained after five successive cycles of reuse.


Assuntos
Ascomicetos/enzimologia , Enzimas Imobilizadas/química , Lipase/química , Dióxido de Silício/química , Estabilidade Enzimática , Óxido de Etileno/química , Concentração de Íons de Hidrogênio , Fenômenos de Química Orgânica , Espaço Pessoal , Fosfatos
12.
J Chromatogr A ; 1626: 461366, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797845

RESUMO

An alternative method for efficient synthesis of urea-functionalized silanes was proposed on the basis of an N, N'-carbonyldiimidazole-mediated acyl-transfer reaction between various amino-containing building blocks. The employment of different parent aminosilanes and alkylamines afforded an array of urea-containing silanes, which were subsequently immobilized onto silica gel to form corresponding urea-embedded alkyl stationary phases for high-performance liquid chromatography. The different substituents on the silicon core of the derivatized silane were found to significantly influence the final chromatographic behaviors. The comparative chromatographic characterization of thus-prepared silica packings with conventional octadecyl (C18) stationary phases revealed that the urea group was beneficial to suppress silanol activity towards basic probes, as well as to increase the water-compatibility of the alkyl stationary phases. The combination of a polar urea moiety and a non-polar long alkyl chain was favorable for an enhanced steric selectivity towards shape-constrained isomers. The polarizability-sensitive feature of such stationary phases made them good candidates for efficient separation of nitro-containing polar substances.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Silanos/química , Ureia/química , Isomerismo , Silanos/síntese química , Sílica Gel/química , Dióxido de Silício/química
13.
Free Radic Res ; 54(7): 556-565, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32854555

RESUMO

This study aimed to develop a procedure for preparing a modified silica-naringin hybrid system. To accomplish, the properties of the obtained material were characterized by FT-IR analysis, UV-Vis spectrophotometry, thermogravimetry, scanning electron microscopy (SEM), and zeta potential. 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to characterize and evaluate the antioxidant activity. The naringin release profile at pH = 1.2 and 7.2 were determined. FT-IR studies confirmed the interaction between the naringin and present carrier. The release study indicated that a release an approximately 20% and 50% of the release occurred in the first 30 min in pH = 1.2 and 7.2, respectively. The thermogravimetry and UV-Vis spectrophotometry analysis allowed us to determine the amount of naringin in the studied hybrid material at the level of several percent. The proposed hybrid material shows good stability, as evidenced by the zeta potential of about +30 and -30 mV in an acidic and alkaline environment, respectively. Antioxidant properties are comparable to those of pure naringin. The results suggest that the obtained hybrid material is a promising product with antioxidant properties.


Assuntos
Flavanonas/química , Depuradores de Radicais Livres/química , Dióxido de Silício/química , Antioxidantes/química , Flavanonas/síntese química , Depuradores de Radicais Livres/síntese química , Compostos de Silício/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
14.
J Chromatogr A ; 1627: 461402, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823107

RESUMO

Surfactants are used in various applications: cosmetics, pharmaceuticals, petrochemicals, environmental, etc. Many of these compounds are polydisperse, and because of this intrinsic polydispersity, it is essential to have a universal detector with a uniform response to quantify them in a simple way. Indeed, Charged Aerosol Detector (CAD) was presented as a universal detector with a uniform response. Thus, in the present study, the CAD response, in a High-Performance Liquid Chromatography - CAD configuration (HPLCCAD), was evaluated using purified alcohol ethoxylated surfactants. A semi-preparative liquid chromatography step using a Hydrophilic interaction chromatography (HILIC) bare silica column (150 mm, 4.6 mm, 2.6 µm) was implemented to prepare eleven homologues of BrijC10, a nonionic surfactant. These homologues differed only by the number of ethylene oxide units. BrijC10 homologues were analyzed by HPLCCAD, using a HILIC bare silica column (150 mm, 2.1 mm, 2.6 µm) to determine the HPLCCAD response factors of purified homologues. From the calibration curves (from 100 to 500 mg.kg-1), their response factors were estimated: differences in response factors were observed and a maximum difference in response factors of 3.6 was obtained. Thus, it could be concluded that CAD hyphenated to HILIC separation did not present a uniform response for this homologue's distribution.


Assuntos
Aerossóis/química , Cromatografia Líquida de Alta Pressão/métodos , Calibragem , Cromatografia Líquida de Alta Pressão/normas , Etil-Éteres/química , Interações Hidrofóbicas e Hidrofílicas , Dióxido de Silício/química , Tensoativos/química
15.
PLoS One ; 15(8): e0237612, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790731

RESUMO

Seventeen glass vessels and twenty glass beads recovered from the excavations at the ancient city of Malindi and the archaeological site of Mambrui in Kenya, east Africa were analysed using electron probe microanalysis (EPMA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results show that all of the glass samples are soda-lime-silica glass. They belong to the high alumina -plant ash glass type, characterised by high alumina and relatively low calcium contents, widely distributed in eastern (10th- 16th centuries AD) and southern Africa (13th - 15th centuries AD), Central Asia (9th- 14th centuries AD) and southeast Asia (12th- 13th centuries AD), made with plant ashes and sands. This is an understudied glass type for which previous research has indicated there were three types. When compared with published research on such glasses using Zr, Ti, Ba, Cr, La, Li, Cs, Na2O, MgO and CaO we have identified at least four different compositional groups of v-Na-Al glass: Types A, B, C and D. By comparing the results with contemporary v-Na-Al glass vessels and beads from Central Asia, Africa, and southeast Asia we show that most of the Malindi and Mambrui glass share similar characteristics to the compositions of Mapungubwe Oblate and some of the Madagascar glass beads from southern Africa. They belong to Type A v-Na-Al glass which is characterised by an elevated level of Ti and Ba and a relatively high ratios of Cr/La, relatively low Zr concentrations and low ratios of Zr/Ti. Differences in Zr, Li, MgO and Na2O concentrations in Type A glass indicates that there are subgroups which might derive from different glass workshop(s) specialising in Type A v-Na-Al glass production. Comparison with the chemical compositions of glass from Ghazni, Afghanistan and Termez, Uzbekistan, and by using lead isotope analysis, we suggest v-Na-Al glass was manufactured in Central Asia and possibly worked into vessels and beads there.


Assuntos
Compostos de Cálcio/química , Vidro/química , Óxidos/química , Plantas/química , Dióxido de Silício/química , Hidróxido de Sódio/química , Oligoelementos/análise , Oligoelementos/história , África Oriental , Óxido de Alumínio , Arqueologia , História do Século XV , História do Século XVI , Oceano Índico , Marcação por Isótopo/métodos , Quênia , Espectrometria de Massas
16.
J Chromatogr A ; 1626: 461354, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797834

RESUMO

The Al-doped mesoporous crystalline material-41 (Al-MCM-41) composite was prepared and applied as fiber coating material of headspace solid-phase microextraction (HS-SPME) for extraction of polycyclic aromatic hydrocarbons (PAHs) from human urine. Five PAHs including acenaphthene, fluorene, phenanthrene, anthracene, and pyrene are chosen as target analytes to evaluate the performance of the material by GC-FID analysis. The mesoporous Al-MCM-41 composite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption measurement, and thermogravimetric analysis. The parameters affecting the extraction efficiency of HS-SPME were investigated. Under the optimal conditions, the method exhibits ideal linearity for target analytes in the range of 0.3-600 ng⋅mL-1 with the coefficients (R2) equal or higher than 0.9906. The enrichment factors are calculated from 540 to 1760. The limits of detection (LODs) and limits of quantitation (LOQs) are between the ranges of 0.06-0.18 and 0.3-0.9 ng⋅mL-1, respectively. The relative standard deviations (RSDs) (n = 5) of intra-day and inter-day are in the ranges of 1.08-7.49% and 2.84-18.3% respectively. The fiber-to-fiber reproducibility (n = 3) is in the range of 6.47-13.9%. The method was successfully applied for the analysis of PAHs in human urine with reasonable recoveries which is ranging from 73.29 to 116.1%.


Assuntos
Alumínio/química , Hidrocarbonetos Policíclicos Aromáticos/urina , Dióxido de Silício/química , Microextração em Fase Sólida/métodos , Adsorção , Cristalização , Humanos , Limite de Detecção , Masculino , Concentração Osmolar , Porosidade , Padrões de Referência , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Fatores de Tempo , Difração de Raios X
17.
Nat Commun ; 11(1): 3858, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737343

RESUMO

Checkpoint blockade therapy has provided noteworthy benefits in multiple cancers in recent years; however, its clinical benefits remain confined to 10-40% of patients with extremely high costs. Here, we design an ultrafast, low-temperature, and universal self-assembly route to integrate immunology-associated large molecules into metal-organic-framework (MOF)-gated mesoporous silica (MS) as cancer vaccines. Core MS nanoparticles, acting as an intrinsic immunopotentiator, provide the niche, void, and space to accommodate antigens, soluble immunopotentiators, and so on, whereas the MOF gatekeeper protects the interiors from robust and off-target release. A combination of MOF-gated MS cancer vaccines with systemic programmed cell death 1 (PD-1) blockade therapy generates synergistic effects that potentiate antitumour immunity and reduce the effective dose of an anti-PD-1 antibody to as low as 1/10 of that for PD-1 blockade monotherapy in E.G7-OVA tumour-bearing mice, with eliciting the robust adaptive OVA-specific CD8+ T-cell responses, reversing the immunosuppressive pathway and inducing durable tumour suppression.


Assuntos
Anticorpos Neutralizantes/farmacologia , Vacinas Anticâncer/farmacologia , Linfoma/terapia , Estruturas Metalorgânicas/farmacologia , Nanopartículas/administração & dosagem , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Animais , Antígenos de Neoplasias/administração & dosagem , Antígenos de Neoplasias/imunologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Vacinas Anticâncer/química , Citotoxicidade Imunológica , Composição de Medicamentos , Feminino , Humanos , Imunidade Inata/efeitos dos fármacos , Imunoterapia/métodos , Linfonodos/efeitos dos fármacos , Linfonodos/imunologia , Linfoma/imunologia , Linfoma/mortalidade , Linfoma/patologia , Estruturas Metalorgânicas/síntese química , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/química , Ovalbumina/administração & dosagem , Ovalbumina/imunologia , Receptor de Morte Celular Programada 1/imunologia , Dióxido de Silício/química , Análise de Sobrevida , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Biophys Chem ; 265: 106441, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32745829

RESUMO

The possibility of immobilizing a protein with antigenic properties on a solid support offers significant possibilities in the development of immunosensors and vaccine formulations. For both applications, the orientation of the antigen should ensure ready accessibility of the antibodies to the epitope. However, an experimental assessment of the orientational preferences necessarily proceeds through the preparation/isolation of the antigen, the immobilization on different surfaces and one or more biophysical characterization steps. To predict a priori whether favorable orientations can be achieved or not would allow one to select the most promising experimental routes, partly mitigating the time cost towards the final product. In this manuscript, we apply a simple computational model, based on united-residue modelling, to the prediction of the orientation of the receptor binding domain of the SARS-CoV-2 spike protein on surfaces commonly used in lateral-flow devices. These calculations can account for the experimental observation that direct immobilization on gold gives sufficient exposure of the epitope to obtain a response in immunochemical assays.


Assuntos
Betacoronavirus/metabolismo , Epitopos/química , Modelos Moleculares , Glicoproteína da Espícula de Coronavírus/metabolismo , Antígenos/química , Antígenos/imunologia , Antígenos/metabolismo , Epitopos/imunologia , Simulação de Acoplamento Molecular , Domínios Proteicos , Dióxido de Silício/química , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Propriedades de Superfície
19.
J Chromatogr A ; 1625: 461325, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709354

RESUMO

We derive a model of band broadening in multiple-open-tubular columns enabling transverse diffusion (MOTTD). In MOTTD columns, the flow channels are straight, parallel, cylindrical tubes arranged in a hexagonal compact array. A mesoporous material or stationary phase (130 Å bridged-ethyl hybrid (BEH) silica support) is filling the volume between the flow channels. The model is based on Giddings' random-walk theory of non-equilibrium chromatography. It is calibrated for the unknown configuration factor, qs, related to the specific geometry of the stationary phase in MOTTD columns. qs values are found based on the best fit of the model to simulated dispersion data obtained by the lattice-Boltzmann method for modelling fluid flow and a random-walk particle-tracking technique to address advective-diffusive transport of the analytes. For the model calibration, simulations are performed for different ratios, ρ, of the average inner diameter of the flow channels to their closest center-to-center distance under retained and non-retained conditions. The model is successfully validated (average relative errors below 10%) under both retained and non-retained conditions. For the same column format (4.6 mm i.d.  ×  150 mm), external porosity, zone retention factor, and relative standard deviation of the distribution of the inner diameters of the flow channels, the derived model reveals the intrinsic advantage of MOTTD columns (center-to-center distance between flow channels of 5 µm and ρ = 0.62) over a conventional column packed with 5 µm 130 Å BEH silica particles and the same multiple porous-layer open-tubular column (MPLOT) disabling transverse dispersion. MOTTD columns are weakly affected by the polydispersity of the inner diameter of the flow channels. Provided MOTTD columns could be prepared at a small feature size of 5 µm or less, they are expected to deliver a significant improvement in column technology relative to current particulate and silica monolithic columns.


Assuntos
Cromatografia/métodos , Modelos Químicos , Calibragem , Simulação por Computador , Difusão , Porosidade , Reprodutibilidade dos Testes , Dióxido de Silício/química
20.
PLoS One ; 15(7): e0236441, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32701973

RESUMO

Biofilms are microbial communities embedded in an extracellular polymeric matrix and display an enhanced tolerance to the action of antimicrobials. The emergence of novel functionalised nanoparticles is considered a promising avenue for the development of biofilm-specific antimicrobial technologies. However, there is a gap in the understanding of interactions between nanoparticles and the biofilm matrix. Particularly, questions are raised on how nanoparticle charge and surface groups play a role in aggregation when in contact with biofilm components. Herein we present the synthesis of four types of silica nanoparticles and undertake an analysis of their interactions with Pseudomonas fluorescens biofilm matrix. The effect of the biofilm matrix components on the charge and aggregation of the nanoparticles was assessed. Additionally, the study focused on the role of matrix proteins, with the in-depth characterisation of the protein corona of each nanoparticle by Liquid Chromatography with Tandem Mass Spectrometry experiments. The protein corona composition is dependent on the nanoparticle type; non-functionalised nanoparticles show less protein selectivity, whereas carboxylate-functionalised nanoparticles prefer proteins with a higher isoelectric point. These outcomes provide insights into the field of biofilm-nanoparticle interactions that can be valuable for the design of new nano-based targeting systems in future anti-biofilm applications.


Assuntos
Biofilmes/efeitos dos fármacos , Nanopartículas Metálicas/química , Pseudomonas fluorescens/efeitos dos fármacos , Dióxido de Silício/farmacologia , Biofilmes/crescimento & desenvolvimento , Cromatografia Líquida , Humanos , Coroa de Proteína/química , Mapas de Interação de Proteínas/efeitos dos fármacos , Pseudomonas fluorescens/crescimento & desenvolvimento , Dióxido de Silício/química , Espectrometria de Massas em Tandem
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