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1.
Chem Commun (Camb) ; 55(77): 11619-11622, 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31501844

RESUMO

Mesoporous organosilica nanoparticles (PHT-PMO) have been prepared from an octa-triethoxysilylated Zn phthalocyanine precursor. These PHT-PMO nanoparticles had no dark toxicity but high phototoxicity when irradiated at 650 nm, and remarkable near-infrared phototoxicity when excited at 760 and 810 nm. The PHT-PMO were then aminated to promote electrostatic complexation with siRNA. Transfection experiments were performed upon NIR irradiation and photochemical internalization was very efficient, leading to 65% luciferase extinction in MCF-7 cancer cells expressing stable luciferase.


Assuntos
Indóis/química , Nanopartículas/química , Compostos Organometálicos/química , Fotoquimioterapia/métodos , RNA Interferente Pequeno/química , Silanos/química , Sobrevivência Celular , Cetrimônio/química , Humanos , Raios Infravermelhos , Luciferases/genética , Células MCF-7 , Processos Fotoquímicos , Porosidade , RNA Interferente Pequeno/metabolismo , Eletricidade Estática , Propriedades de Superfície
2.
J Nanobiotechnology ; 17(1): 87, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387604

RESUMO

BACKGROUND: Adoptive T cell-transfer (ATC) therapy is a highly promising cancer-treatment approach. However, in vivo-administered T cells tend to disperse, with only a small proportion reaching the tumour. To remedy this, magnetic targeting of T cells has been recently explored. Magnetic nanoparticles (MNPs) functionalised with antibodies were attached to effector T cells and magnetically recruited to tumour sites under MRI guidance. In this study, we investigated whether 3-aminopropyl-triethoxysilane (APS)-coated MNPs directly attached to CD8+ T cell membranes could also magnetically target and accumulate tumour-specific CD8+ T cells in solid tumours using an external magnetic field (EMF). As it has been shown that T cells associated with APS-coated MNPs are retained in lymph nodes (LNs), and tumour-draining LNs are the most common sites of solid-tumour metastases, we further evaluated whether magnetic targeting of APS-MNP-loaded CD8+ T cells could cause them to accumulate in tumour-draining LNs. RESULTS: First, we show that antigen-specific CD8+ T cells preserve their antitumor activity in vitro when associated with APS-MNPs. Next, we demonstrate that the application of a magnetic field enhanced the retention of APS-MNP-loaded OT-I CD8+ T cells under flow conditions in vitro. Using a syngeneic mouse model, we found similar numbers of APS-MNP-loaded OT-I CD8+ T cells and OT-I CD8+ T cells infiltrating the tumour 14 days after cell transfer. However, when a magnet was placed near the tumour during the transfer of tumour-specific APS-MNP-loaded CD8+ T cells to improve tumour infiltration, a reduced percentage of tumour-specific T cells was found infiltrating the tumour 14 days after cell transfer, which was reflected in a smaller reduction in tumour size compared to tumour-specific CD8+ T cells transferred with or without MNPs in the absence of a magnetic field. Nonetheless, magnet placement near the tumour site during cell transfer induced infiltration of activated tumour-specific CD8+ T cells in tumour-draining LNs, which remained 14 days after cell transfer. CONCLUSIONS: The use of an EMF to improve targeting of tumour-specific T cells modified with APS-MNPs reduced the percentage of these cells infiltrating the tumour, but promoted the retention and the persistence of these cells in the tumour-draining LNs.


Assuntos
Transferência Adotiva , Linfócitos T CD8-Positivos/transplante , Linfonodos/patologia , Linfócitos do Interstício Tumoral/imunologia , Nanopartículas de Magnetita/química , Neoplasias Experimentais/terapia , Animais , Linfócitos T CD8-Positivos/imunologia , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular , Proliferação de Células , Sobrevivência Celular , Feminino , Linfonodos/imunologia , Ativação Linfocitária , Linfócitos do Interstício Tumoral/patologia , Camundongos Endogâmicos C57BL , Transplante de Neoplasias , Neoplasias Experimentais/imunologia , Neoplasias Experimentais/patologia , Propilaminas/química , Silanos/química
3.
Pharm Res ; 36(10): 147, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31414240

RESUMO

PURPOSE: The aim was to design and thoroughly characterize monodisperse Fe3O4@SiO2-Ag nanoparticles with strong antibacterial properties, which makes them a candidate for targeting bacterial infections. METHODS: The monodisperse Fe3O4 nanoparticles were prepared by oleic acid-stabilized thermal decomposition of Fe(III) oleate; the particles were coated with silica shell using a water-in-oil reverse microemulsion, involving hydrolysis and condensation of tetramethyl orthosilicate. Resulting Fe3O4@SiO2 particles were modified by (3-mercaptopropyl)trimethoxysilane to introduce 1.1 mmol SH/g. Finally, the Fe3O4@SiO2-SH nanoparticles were decorated with silver nanoclusters formed by reduction of silver nitrate with NaBH4. The particles were analyzed by FTIR, X-ray photoelectron and atomic absorption spectroscopy, dynamic light scattering and vibrating sample magnetometry. The antibacterial activity of the Fe3O4@SiO2 and Fe3O4@SiO2-Ag nanoparticles was tested against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria cultivated on Luria agar plates or in Luria broth. RESULTS: The superparamagnetic Fe3O4@SiO2-Ag nanoparticles (21 nm in diameter; saturation magnetization 26 A∙m2/kg) were successfully obtained and characterized. Inhibitory and toxic effects against bacteria were documented by incubation of the Fe3O4@SiO2-Ag nanoparticles with Staphylococcus aureus and Escherichia coli. CONCLUSIONS: The combination of magnetic properties together with bactericidal effects is suitable for the disinfection of medical instruments, water purification, food packaging, etc.


Assuntos
Antibacterianos/química , Nanopartículas de Magnetita/química , Prata/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Ácido Oleico/química , Tamanho da Partícula , Silanos/química , Dióxido de Silício/química , Prata/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície
4.
Anal Bioanal Chem ; 411(21): 5415-5422, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31317237

RESUMO

Isoelectric focusing (IEF), a powerful technique for protein separation and enrichment, was successfully integrated into microfluidic paper-based analytical devices (µPADs) in this work. The µPADs for isoelectric focusing were fabricated by octadecyltrichlorosilane (OTS) silanization and subsequent region-selective plasma treatment. The system of IEF on µPADs could be easily assembled. And a series of conditions of the system were investigated, including the suitable concentration of ampholyte to create good pH gradient, the effect of polyvinylpyrrolidone (PVP) on electroosmotic flow (EOF) suppression, and focusing voltage applied on the paper channel. After optimization, simultaneous separation and enrichment of protein sample containing myoglobin and cytochrome C was successfully demonstrated. Besides, parallel IEF on multichannels were also achieved for the separation of multiple protein samples on one single chip, and their performance was compared with that of the conventional gel-IEF system. The developed IEF on µPADs exhibits appealing features such as low cost, simplicity, and disposability and are believed to have great application potentials.


Assuntos
Focalização Isoelétrica , Técnicas Analíticas Microfluídicas/métodos , Papel , Citocromos c/isolamento & purificação , Eletro-Osmose , Concentração de Íons de Hidrogênio , Mioglobina/isolamento & purificação , Povidona/química , Silanos/química
5.
Environ Sci Pollut Res Int ; 26(24): 25359-25371, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31256408

RESUMO

In the present article, Fe3O4@TiO2 core/shell (FT) linked to graphene was fabricated by sol-gel technique as a photocatalyst and was employed for the solar degradation of cationic methylene blue (MB) in aqueous solution. The prepared core/shells were linked to graphene oxide (FTGO) and reduced graphene oxide (FTRGO) via embedding into 3-aminopropyltrimethoxysilane (APS). The structure of this magnetic composition was characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and BET surface area measurements. The significance of the composite structure in photocatalytic degradation was spectrophotometrically tested by blending the obtained powders with wastewater containing methylene blue under solar irradiation. The appropriate dosage of APS to link the Fe3O4@TiO2 core/shell onto GO and RGO surfaces was determined to be 1 ml per gram of FT. The kinetic studies were performed to investigate the effects of different parameters, such as composition structure, APS dosage, and repeatability. Kinetic data are well fitted by a first-order model with a high correlation coefficient. Regardless of the prominent advantage of composites in magnetic powder separation, the Fe3O4@TiO2 core/shell linked to graphene oxide is an efficient composite in comparison to FTRGO for the dye degradation without losing the original activity and stability.


Assuntos
Grafite/química , Azul de Metileno/química , Processos Fotoquímicos , Silanos/química , Catálise , Cinética , Magnetismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Compostos Orgânicos , Óxidos/química , Luz Solar , Difração de Raios X
6.
Chemosphere ; 233: 890-895, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340416

RESUMO

The reduction of halocarbons by NADH models and NADH under ambient conditions is reported as a new type of reactivity pointing towards a hitherto unknown disruptive pathway for NADH/NADPH-dependent processes. The reaction was studied with the omnipresent pesticide DDT, the inhalation anesthetic halothane, and several simple halocarbons. The halide-hydride exchange represents a biochemical equivalent for the reduction of halocarbons by traditional synthetic reagents like silanes (R3Si-H) and stannanes (R3Sn-H). High precision thermochemical calculations (CBS-QB3) reveal the carbon-hydrogen bond dissociation energy of NADH (70.8 kcal·mol-1) to be lower than that of stannane (SnH4: 78.1 kcal·mol-1), approaching that of the elusive plumbane (PbH4: 68.9 kcal·mol-1). The ready synthetic accessibility of NADH models, their low carbon-hydrogen bond dissociation energy, and their dehalogenation activity in the presence of air and moisture recommend these compounds as substitutes for the air-sensitive or toxic metal hydrides currently employed in synthesis.


Assuntos
DDT/metabolismo , Poluentes Ambientais/metabolismo , Recuperação e Remediação Ambiental/métodos , Halotano/metabolismo , Hidrocarbonetos Halogenados/análise , Hidrocarbonetos Halogenados/metabolismo , NAD/metabolismo , Carbono/química , Hidrogênio/química , Ligações de Hidrogênio , Indicadores e Reagentes , Silanos/química , Compostos de Estanho/química
7.
Anal Chim Acta ; 1078: 151-160, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358213

RESUMO

Herein, we report a new signal amplification scheme for quantitative biochemical analysis based on gold nanoparticle (GNPs) catalyzed polymerization of transparent silane solution to milky white and turbid siloxane. Using immunoassay as a proof of concept, GNP labeled immunoprobe was used to bind captured antigen and catalyse the polymerization reaction allowing sensitive biochemical investigation. The polymerization reaction was optimized for standard 96 well polystyrene microtiter plates and we discovered that sodium lactate acts as an enhancer in the polymerization reaction as it reduces detection time to merely 30 min. The sensing strategy was applied to detection and quantification of Salmonella Typhimurium in water and egg samples and the platform showed excellent visibly quantifiable analytical response up to 100 cells mL-1. Furthermore, clinical utility and potential of the method was validated by detecting Vi capsular polysaccharide (Vi antigen) responsible for typhoidal Salmonellosis in human serum in sandwich format with a detection limit of 1 ng mL-1. The method serves as the first report towards nanoparticle triggered polymerization for development of rapid and low cost quantitative biochemical assay.


Assuntos
Ouro/química , Imunoensaio/métodos , Nanopartículas Metálicas/química , Polissacarídeos Bacterianos/sangue , Salmonella typhimurium/isolamento & purificação , Siloxanas/síntese química , Animais , Anticorpos/imunologia , Galinhas , Água Potável/microbiologia , Ovos/microbiologia , Contaminação de Alimentos/análise , Humanos , Limite de Detecção , Tamanho da Partícula , Polimerização , Polissacarídeos Bacterianos/imunologia , Estudo de Prova de Conceito , Salmonella typhimurium/imunologia , Silanos/química , Temperatura Ambiente
8.
J Chromatogr A ; 1603: 297-310, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31227363

RESUMO

Surface modification of porous glass beads by ethanol-based 3-mercaptopropyltrimethoxysilane (MPTMS) grafting solutions is directly evidenced by nitrogen adsorption, elemental analysis, thermogravimetry, infrared and 29Si CP MAS NMR spectroscopy. Furthermore, the energetic characterization of the surface is essential to understand comprehensively the physico-chemical interactions between the pristine and MPTMS-modified surface and its gas/liquid-phase environment. In this study, inverse gas chromatography (IGC) is used to characterize the surface properties of porous glass (PG). By means of IGC at infinite dilution (IGC-ID), the dispersive component of the surface energy (γsd), the enthalpy and entropy of adsorption of C6-C10 hydrocarbon probes were determined at temperatures between 30 and 120 °C. The specific component of the surface energy (γssp) at the temperature of 120 °C has been obtained via the Van Oss theory and a least-squares procedure evaluating the IGC data of 8 polar probe molecules collectively. After surface silylation, the total surface energy (γst) decreased from 402 to 255 mJ/m² indicating both a reduced wettability and an increased hydrophobicity of the MPTMS-modified PG. Moreover, the acidity/basicity parameters according to the Van Oss and the Gutmann approach indicated that the acidity of the PG surface decreases by MPTMS grafting. Using n-octane and isopropanol probes, IGC at finite concentration (IGC-FC) was applied to obtain their adsorption isotherms and subsequently the BET specific surface areas. In addition, the surface heterogeneity of the studied PGs was also computed. The energy distribution functions of adsorption sites were monomodal (peak maximum at about 22 kJ/mol) for the n-octane probe, while isopropanol revealed a bimodal distribution function (maxima at about 18 and 25 kJ/mol) on both pristine and MPTMS-modified PG. Furthermore, the proportion of high energy sites (apparently assigned to SiOH groups) has been reduced by surface modification from 65% to only 35% despite a high surface coverage of ˜10 MPTMS species/nm2. These findings are in agreement with the results of 29Si CP MAS NMR measurements and are supported by DFT calculations on the adsorption of isopropanol and n-octane on the surface of a silica cluster model.


Assuntos
Cromatografia Gasosa/métodos , Dióxido de Silício/química , 2-Propanol/química , Ácidos/química , Adsorção , Alcanos/química , Teoria da Densidade Funcional , Entropia , Espectroscopia de Ressonância Magnética , Conformação Molecular , Nitrogênio/química , Porosidade , Silanos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Temperatura Ambiente , Termogravimetria
9.
Carbohydr Polym ; 220: 71-78, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31196552

RESUMO

In this work, we report a convenient method of grafting non-leachable bioactive amine functions onto the surface of bacterial cellulose (BC) nanofibrils, via a simple silylation treatment in water. Two different silylation protocols, involving different solvents and post-treatments were envisaged and compared, using 3-aminopropyl-trimethoxysilane (APS) and (2-aminoethyl)-3-aminopropyl-trimethoxysilane (AEAPS) as silylating agents. In aqueous and controlled conditions, water-leaching resistant amino functions could be successfully introduced into BC, via a simple freeze-drying process. The silylated material remained highly porous, hygroscopic and displayed sufficient thermal stability to support the sterilization treatments generally required in medical applications. The impact of the silylation treatment on the intrinsic anti-bacterial properties of BC was investigated against the growth of Escherichia coli and Staphylococcus aureus. The results obtained after the in vitro studies revealed a significant growth reduction of S. aureus within the material.


Assuntos
Materiais Biomédicos e Odontológicos , Celulose/farmacologia , Gluconacetobacter/metabolismo , Membranas/química , Nanofibras , Silanos/química , Antibacterianos/farmacologia , Materiais Biomédicos e Odontológicos/química , Materiais Biomédicos e Odontológicos/farmacologia , Escherichia coli/efeitos dos fármacos , Nanofibras/química , Nanofibras/uso terapêutico , Staphylococcus aureus/efeitos dos fármacos
10.
Nanomedicine (Lond) ; 14(9): 1095-1107, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31066644

RESUMO

Aim: Polyanionic carbosilane dendrimers have been shown to be safe and block human immunodeficiency virus type 1 (HIV-1) infection in a multifunctional manner. The aim of this study is to evaluate the appearance of HIV-1 resistance mutations after treatment with polyanionic carbosilane dendrimers. Materials & methods: A resistance mutation assay was performed on MT2 cells, viral quantity was measured by ELISA HIVp24gag and titration was carried out on TZM.bl. Next generation sequencing for HIV-1 Env was performed on G1-S4 or G2-S16 dendrimers supernatants. Results: Data showed the appearance of mutation resistance to G1-S4 treatment, inducing three significant mutations. G2-S16 did not generate any mutations and, furthermore, inhibited G1-S4-resistant viruses. Conclusion: G1-S4 treatment generates significant mutations in HIV-1NL4.3. G2-S16 does not generate resistance-associated mutation, suggesting that G2-S16 is safe as a HIV-entry inhibitor.


Assuntos
Fármacos Anti-HIV/farmacologia , Dendrímeros/farmacologia , HIV-1/efeitos dos fármacos , Silanos/farmacologia , Linhagem Celular , Dendrímeros/química , Farmacorresistência Viral , Proteína gp120 do Envelope de HIV/genética , HIV-1/fisiologia , Humanos , Mutação , Silanos/química , Falha de Tratamento , Internalização do Vírus/efeitos dos fármacos
11.
Int J Nanomedicine ; 14: 2397-2413, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31040664

RESUMO

Background: Multimodal contrast agents with low toxicity and targeted modification have opened up new possibilities for specific imaging of breast cancer and shown broad application prospects in biomedicine and great potential for clinical transformation. In this work, a potential multifunctional imaging agent was developed by doping Fe into hollow silica nanoparticles (HS-Fe NPs), followed by modification with specific anti-HER2 antibodies, enabling the NPs to have dual-mode ultrasound (US)-magnetic resonance (MR)-specific imaging capacity with low toxicity. Methods: Anti-HER2 antibodies were conjugated to silane-polyethylene glycol (PEG)-COOH-modified HS-Fe (HS-Fe-PEG) NPs to produce HER2-targeted HS-Fe-PEG (HS-Fe-PEG-HER2) NPs. The toxicity of HS-Fe-PEG-HER2 NPs on targeted cells in vitro and blood and organ tissue of mice in vivo was investigated. Distribution in vivo was also studied. Confocal laser-scanning microscopy and flow cytometry were used to evaluate the targeting ability of HS-Fe-PEG-HER2 NPs in vitro. US and MR instruments were used for imaging both in vivo and in vitro. Results: The obtained HS-Fe-PEG-HER2 NPs (average diameter 234.42±48.76 nm) exhibited good physical properties and biosafety. In solution, they showed obvious enhancement of the US signal and negative contrast in T 2-weighted MR imaging. The binding rate of HS-Fe-PEG-HER2 NPs to targeted cells (SKBR3) was 78.97%±4.41% in vitro. US and MR imaging in vivo confirmed that the HS-Fe-PEG-HER2 NPs were delivered passively into the tumor region of SKBR3 and bound specifically to tumor cells. Target enhancement was better than untargeted and targeted competition groups. Conclusion: HS-Fe-PEG-HER2 NPs have potential as a low-cytotoxicity and dual-mode US-MR-specific imaging agent.


Assuntos
Neoplasias da Mama/metabolismo , Meios de Contraste/química , Ferro/química , Imagem por Ressonância Magnética , Nanopartículas/química , Dióxido de Silício/química , Ultrassonografia , Animais , Morte Celular , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos Endogâmicos BALB C , Nanopartículas/ultraestrutura , Polietilenoglicóis/química , Receptor ErbB-2/metabolismo , Silanos/química , Distribuição Tecidual
12.
Int J Mol Sci ; 20(8)2019 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-31003413

RESUMO

Gamma-ray radiation was used as a clean and easy method for turning the physicochemical properties of graphene oxide (GO) in this study. Silane functionalized-GO were synthesized by chemically grafting 3-aminopropyltriethoxysilane (APTES) and 3-glycidyloxypropyltrimethoxysilane (GPTES) onto GO surface using gamma-ray irradiation. This established non-contact process is used to create a reductive medium which is deemed simpler, purer and less harmful compared conventional chemical reduction. The resulting functionalized-GO were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), and Raman spectroscopy. The chemical interaction of silane with the GO surface was confirmed by FT-IR. X-ray diffraction reveals the change in the crystalline phases was due to surface functionalization. Surface defects of the GO due to the introduction of silane mioties was revealed by Raman spectroscopy. Thermogravimetric analysis of the functionalized-GO exhibits a multiple peaks in the temperature range of 200-650 °C which corresponds to the degradation of chemically grafted silane on the GO surface.


Assuntos
Grafite/química , Compostos de Organossilício/química , Propilaminas/química , Silanos/química , Compostos de Epóxi/síntese química , Compostos de Epóxi/química , Compostos de Epóxi/efeitos da radiação , Raios gama , Grafite/síntese química , Grafite/efeitos da radiação , Microscopia Eletrônica de Varredura , Compostos de Organossilício/efeitos da radiação , Propilaminas/síntese química , Propilaminas/efeitos da radiação , Silanos/síntese química , Silanos/efeitos da radiação , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Propriedades de Superfície/efeitos da radiação , Temperatura Ambiente , Termogravimetria , Difração de Raios X
13.
Prep Biochem Biotechnol ; 49(6): 590-596, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30929562

RESUMO

In this study, 6-phosphogluconate dehydrogenase was covalently immobilized onto the N-2-aminoethyl-3-aminopropyltriethoxysilane (APTES) modified core-shell Fe3O4@SiO2 magnetic nanoparticles (ASMNPs) using glutaraldehyde (GA). Immobilization of 6PGDH on ASMNPs was confirmed using fourier transform-infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analysis. The NADP+ conversion ratio, the reusability, thermal, and storage stability of the immobilized 6PGDH were determined and compared with those of the free enzyme. The maximum retention of enzyme activity reached to 96% when the enzyme was immobilized on ASMNPs activated with monomer form of GA. Although the thermal stability of free and immobilized enzymes was similar, at 30 °C, the immobilized 6PGDH showed the improved thermal stability at 40 °C and 50 °C compared with free 6PGDH. While the free 6PGDH only converted 33% of NADP+ in reaction medium upon 480 s, the immobilized 6PGDH performed 56% conversion of NADP+ at same time. The immobilized 6PGDH retained 62% of its initial activity up to the fifth cycle and 35% of its initial activity after 22 days of storage at 4 °C.


Assuntos
Enzimas Imobilizadas/química , Nanopartículas de Magnetita/química , Fosfogluconato Desidrogenase/química , Estabilidade Enzimática , Glutaral/química , Propilaminas/química , Silanos/química , Dióxido de Silício/química , Temperatura Ambiente
14.
Org Lett ; 21(9): 3451-3455, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-30993986

RESUMO

Site selective amide reductions of the cyclic undecapeptide, cyclosporine A, have been developed using the combination of a heteroleptic borane catalyst and a silane reductant. Tertiary silane Me2EtSiH provides two unique cyclosporine A derivatives, one of which can be readily diversified in subsequent reactions. The secondary silane Et2SiH2 enables divergent reactivity that uses a free hydroxyl group to direct the reduction. The transient O-silyl hemiaminal intermediate of this reduction can additionally be trapped by reducing to the amine or by reductive cyanation.


Assuntos
Amidas/química , Ciclosporina/química , Peptídeos Cíclicos/química , Aminas/química , Boranos/química , Catálise , Oxirredução , Silanos/química
15.
Analyst ; 144(11): 3525-3532, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31020954

RESUMO

Silver nanoparticles were coated on a glass stir bar by overnight exposure of the bar to the nanoparticle solution, using 3-aminopropyltriethoxysilane as a binding agent and were used for the extraction of heavy metal Fe3+, Cu2+, Pb2+ and Zn2+ cations from water samples after their complexation with the ligand 1-(2-pyridylazo)-2-naphthol, followed by their determination by high performance liquid chromatography. Various parameters affecting the extraction were evaluated by one variable-at-a-time and Box-Behnken design methods and optimized. Six independent variables, the pH and ionic strength of the solution, the Triton X-114 (surfactant) concentration, amount of ligand, and adsorption and desorption times, were coded as A, B, C, D, E and F at three various levels (-1, 0, and 1). The linear ranges of the technique were 0.5-250.0 µg L-1 for all four analytes. Under the optimum conditions, the limits of detection were calculated as 0.08, 0.11, 0.12 and 0.17 µg L-1 for copper, iron, lead and zinc, respectively. The technique was used for the determination of these cations in drinking water samples.


Assuntos
Água Potável/análise , Nanopartículas Metálicas/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Adsorção , Fracionamento Químico/instrumentação , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão , Vidro/química , Ligantes , Limite de Detecção , Metais Pesados/química , Naftóis/química , Propilaminas/química , Reprodutibilidade dos Testes , Silanos/química , Prata/química , Poluentes Químicos da Água/química
16.
Environ Sci Pollut Res Int ; 26(16): 16716-16726, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30993564

RESUMO

In this study, the cellulose nanocrystals (CNC) obtained by acid hydrolysis of microcrystalline cellulose (MCC) are customized by suspension to obtain a spherical CNC hydrogel. The N-(2-aminoethyl) (3-amino-propyl) methyldimethoxyansile (AEAPMDS) preparation was grafted to spherical CNC hydrogel using a water phase heat treatment. Finally, aerogel samples were obtained by tert-butanol replacement and freeze-drying. The test results confirmed that the aminosilane was grafted on CNC. Electron micrographs and N2 sorption isotherms showed that the pores of the aerogel were partially blocked due to the introduction of AEAPMDS, and the specific surface area was decreased. Due to the presence of chemisorption, the amount of CO2 adsorbed at a pressure of 3 bar by the modified aerogel (2.63 mmol/g) was greatly improved compared with the unmodified aerogel (0.26 mmol/g), and the adsorption results were fit well by the Langmuir model. Thus, our experiments provided the opportunity to develop a new CO2 absorbent material.


Assuntos
Dióxido de Carbono/análise , Celulose/química , Gases de Efeito Estufa/análise , Hidrogéis/química , Nanopartículas/química , Silanos/química , Adsorção , Hidrólise , Propriedades de Superfície
17.
Mater Sci Eng C Mater Biol Appl ; 100: 315-322, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948067

RESUMO

Herein appropriateness of nonfunctionalized mesoporous silica nanoparticles SBA-15 and functionalized with (3-chloropropyl)triethoxysilane (→ SBA-15~Cl) and (3-aminopropyl)triethoxysilane (→ SBA-15~NH2) on delivery of physically adsorbed Ph3Sn(CH2)6OH (Sn6) is evaluated. Fluorescent nanomaterial, bearing isatoic moiety, loaded with Sn6 (→ SBA-15~NF|Sn6) was used for cellular uptake study. The fluorescent nanomaterial is efficiently acquired and distributed into the cytoplasm of the cells even after 2 h of cultivation. According to the attained data, all SBA-15 materials loaded with Sn6 diminished cellular viability in dose dependent manner while carriers alone (SBA-15, SBA-15~Cl, SBA-15~NH2) did not show cytotoxicity against B16 cells. According to the MC50 values structural modification of SBA-15 did not improve the efficacy of tested drug. While progressive apoptosis was detected upon the treatment with SBA-15|Sn6, exposure of cells to SBA-15~NH2|Sn6 revealed extinguished apoptosis in time, accompanied with lower caspase activity. This effect is probably due to triggered autophagic process under the treatment with the SBA-15~NH2|Sn6, thus opposed to apoptosis. Presented results suggested that functionalization of SBA-15 was not beneficial for the efficacy of loaded drug, thus, all of them are almost equally efficient considering loaded Sn6 content. Importantly, functionalization of SBA-15 does have an influence on the mode of action and differentiation inducing properties.


Assuntos
Compostos Orgânicos de Estanho/química , Dióxido de Silício/química , Anidridos/química , Animais , Corantes Fluorescentes/química , Camundongos , Nanopartículas/química , Nanopartículas/ultraestrutura , Porosidade , Propilaminas/química , Silanos/química , ortoaminobenzoatos/química
18.
J Mater Sci Mater Med ; 30(4): 43, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30929122

RESUMO

Robust cell adhesion is known to be necessary to promote cell colonization of biomaterials and differentiation of progenitors. In this paper, we propose the functionalization of Silicon Oxycarbide (SiOxCy) nanowires (NWs) with 3-mercaptopropyltrimethoxysilane (MPTMS), a molecule containing a terminal -SH group. The aim of this functionalization was to develop a surface capable to adsorb proteins and promote cell adhesion, proliferation and a better deposition of extracellular matrix. This functionalization can be used to anchor other structures such as nanoparticles, proteins or aptamers. It was observed that surface functionalization markedly affected the pattern of protein adsorption, as well as the in vitro proliferation of murine osteoblastic cells MC3T3-E1, which was increased on functionalized nanowires (MPTMS-NWs) compared to bare NWs (control) (p < 0.0001) after 48 h. The cells showed a better adhesion on MPTMS-NWs than on bare NWs, as confirmed by immunofluorescence studies on the cytoskeleton, which showed a more homogeneous vinculin distribution. Gene expression analysis showed higher expression levels for alkaline phosphatase and collagen I, putative markers of the osteoblast initial differentiation stage. These results suggest that functionalization of SiOxCy nanowires with MPTMS enhances cell growth and the expression of an osteoblastic phenotype, providing a promising strategy to improve the biocompatibility of SiOxCy nanowires for biomedical applications.


Assuntos
Adesão Celular/efeitos dos fármacos , Nanofios/química , Osteoblastos/efeitos dos fármacos , Compostos de Silício/farmacologia , Compostos de Sulfidrila/farmacologia , Tecidos Suporte/química , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Teste de Materiais , Camundongos , Nanofios/efeitos adversos , Osteoblastos/citologia , Osteoblastos/fisiologia , Osteogênese/efeitos dos fármacos , Espectroscopia Fotoeletrônica , Silanos/química , Silanos/farmacologia , Compostos de Silício/química , Compostos de Sulfidrila/química , Propriedades de Superfície , Tecidos Suporte/efeitos adversos
19.
Anal Chim Acta ; 1062: 68-77, 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-30947997

RESUMO

In this study, a sensitive immunosensor was developed for the first time for p21-activated kinase 2 (PAK 2) detection. In the design of the immunosensor, 3-glycidoxypropyltrimethoxysilane (GPTMS) was utilized as an ITO electrode modification material for anti-PAK 2 antibody immobilization. This molecule had epoxy group, which was reactive to amino groups of antibodies. Anti-PAK 2 antibodies were also used as biomolecules for sensitive interaction for PAK 2 antigen. In the presence of PAK 2 antigens, high impedance signal was observed when the process followed by using Electrochemical Impedance Spectroscopy technique (EIS). Apart from EIS technique, Cyclic Voltammetry (CV), Square Wave Voltammetry (SWV) and Single Frequency Impedance (SFI) techniques were utilized. Microscopic surface characterizations of immunosensor fabrication steps were performed by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The immunosensor exhibited good sensitivity and selectivity for PAK 2 antigen detection. A linear calibration curve between EIS response and PAK 2 concentration was obtained in the range of 0.005-0.075 pg/mL with the detection limit of 1.5 fg/mL. It had good repeatability, excellent reproducibility and high stability. Additionally, this immunosensor can be reused by simple application protocol. Furthermore, it had good recovery for PAK 2 antigen detection in human serum samples. The good recovery illustrated that the developed immunosensor was a promising tool for PAK 2 detection in practical applications.


Assuntos
Biomarcadores Tumorais/sangue , Silanos/química , Compostos de Estanho/química , Quinases Ativadas por p21/sangue , Técnicas Biossensoriais , Espectroscopia Dielétrica , Técnicas Eletroquímicas , Eletrodos , Humanos
20.
Analyst ; 144(9): 3128-3135, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-30931447

RESUMO

Salbutamol (SAL) is one of the most widely abused feed additives in animal husbandry. Selective enrichment of SAL from complex biological samples is a key step for the analysis of SAL. Herein, we present SAL-imprinted magnetic nanoparticles (MNPs) as an ideal sorbent for selective enrichment of SAL. The SAL-imprinted MNPs were prepared according to the newly reported boronate affinity oriented surface imprinting. The prepared imprinted MNPs exhibited several significant advantages, such as excellent selectivity towards SAL, superb tolerance to interferences, fast binding equilibrium and easy manipulation, which made the obtained imprinted MNPs an ideal sorbent for selective enrichment. The feasibility of SAL-imprinted MNPs for real samples was well demonstrated by the analysis of trace SAL in pig liver. Because of their highly desirable properties, the SAL-imprinted MNPs could find more applications in the analysis of SAL.


Assuntos
Albuterol/análise , Ácidos Borônicos/química , Nanopartículas de Magnetita/química , Adsorção , Albuterol/química , Animais , Fígado/química , Impressão Molecular/métodos , Polimerização , Silanos/química , Suínos
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