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1.
Nanotoxicology ; 14(7): 968-984, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32633691

RESUMO

Rich vacancies of semiconductor nanomaterials (NMs) give rise to great enhancement of their physical and chemical properties such as magnetic, catalytic, optical, etc. These NMs possessing extensive applications could inevitably enter into the environment and increase the toxic effects on organisms, so it is imperative to investigate the cytotoxicity of NMs with different types of vacancies. Here, one-dimensional cobalt selenide (CoSe2) NMs with different vacancies were synthesized through the same precursor while calcined at different temperatures (P-CoSe2 which calcined at 200 °C and N-CoSe2 which calcined at 230 °C). According to the positron annihilation spectrum, the VSeSe vacancy associate in P-CoSe2 was endowed with two positive charges, while the VCoCoCoSeSe vacancy associate in N-CoSe2 possessed four negative charges. Cell viability assays revealed that N-CoSe2 had higher toxicity to macrophages than P-CoSe2, which was attributed to higher levels of intracellular reactive oxygen species induced by N-CoSe2. Further investigation showed that N-CoSe2 had higher affinity to the mitochondrion-targeting peptide, leading to its preferential distribution in the mitochondria and consequent induction of mitochondrial superoxide production. In contrast, P-CoSe2 exhibited higher affinity to the endoplasmic reticulum (ER)-targeting peptide, facilitating its preferential distribution in the ER and the nuclei and causing higher damage to both organelles as compared to N-CoSe2. These results demonstrated that type of surface vacancies significantly affected biodistribution of NMs in subcellular organelles, which contributed to differential biological behaviors of the NMs.


Assuntos
Apoptose/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Macrófagos Alveolares/efeitos dos fármacos , Nanoestruturas/toxicidade , Compostos de Selênio/toxicidade , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Humanos , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/patologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Nanoestruturas/química , Coroa de Proteína/química , Ratos , Espécies Reativas de Oxigênio/metabolismo , Compostos de Selênio/química , Solubilidade , Propriedades de Superfície , Distribuição Tecidual
2.
Nat Commun ; 11(1): 2664, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471982

RESUMO

Controlling the chemical glycosylation reaction remains the major challenge in the synthesis of oligosaccharides. Though 1,2-trans glycosidic linkages can be installed using neighboring group participation, the construction of 1,2-cis linkages is difficult and has no general solution. Long-range participation (LRP) by distal acyl groups may steer the stereoselectivity, but contradictory results have been reported on the role and strength of this stereoelectronic effect. It has been exceedingly difficult to study the bridging dioxolenium ion intermediates because of their high reactivity and fleeting nature. Here we report an integrated approach, using infrared ion spectroscopy, DFT computations, and a systematic series of glycosylation reactions to probe these ions in detail. Our study reveals how distal acyl groups can play a decisive role in shaping the stereochemical outcome of a glycosylation reaction, and opens new avenues to exploit these species in the assembly of oligosaccharides and glycoconjugates to fuel biological research.


Assuntos
Química Computacional/métodos , Oligossacarídeos/síntese química , Compostos de Selênio/química , Configuração de Carboidratos , Galactose/química , Glucose/química , Glicosilação , Manose/química , Espectrofotometria Infravermelho
3.
PLoS One ; 15(5): e0232184, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32369508

RESUMO

The ternary chalcogenide Cu3VSe4 (CVSe) with sulvanite structure has been theoretically predicted to be a promising candidate for photovoltaic applications due to its suitable bandgap for solar absorption and the relatively earth-abundant elements in its composition. To realize the absorber layer via an inexpensive route, printed thin-films could be fabricated from dispersions of nano-sized Cu3VSe4 precursors. Herein, cubic Cu3VSe4 nanocrystals were successfully synthesized via a hot-injection method. Similar with reported Cu3VS4 nanocrystals, Cu3VSe4 nanocrystals with cubic structure exhibit three absorption bands in the UV-Visible range indicative of a potential intermediate bandgap existence. A thin film fabricated by depositing the nanoparticles Cu3VSe4 on FTO coated glass substrate, exhibited a p-type behavior and a photocurrent of ~ 4 µA/cm2 when measured in an electrochemical cell setting. This first demonstration of photocurrent exhibited by a CVSe nanocrystals thin film signifies a promising potential in photovoltaic applications.


Assuntos
Nanopartículas/química , Compostos de Selênio/química , Compostos de Selênio/síntese química , Técnicas Eletroquímicas , Nanopartículas/ultraestrutura , Tamanho da Partícula , Processos Fotoquímicos , Semicondutores
4.
Chemosphere ; 254: 126868, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32348924

RESUMO

The increasing application of Quantum Dots (QDs) is cause of concern for the potential negative effects for the ecosystem, especially in soils that may act as a sink. In this study, soil leaching experiments were performed in quartz sand packed columns to investigate the behavior of core-shell CdSe/ZnS QDs coated with either small ligands (TGA-QDs) or more complex polymers (POAMA-QDs). Fluorescence emission was compared to mass spectrometric measurements to assess the nanoparticles (NPs) state in both the leachate (transported species) and porous media (deposited amounts). Although both QDs were strongly retained in the column, large differences were observed depending on their capping ligand stability. Specifically, for TGA-QDs elution was negligible and the retained fraction accumulated in the top-columns. Furthermore, 74% of the NPs were degraded and 38% of the Se was found in the leachate in non-NPs state. Conversely, POAMA-QDs were recovered to a larger extent (78.1%), and displayed a higher transport along the soil profile. Further experiments with altered NPs showed that homo-aggregation of the QDs prior injection determined a reduced mobility but no significant changes in their stability. Eventually, ageing of the NPs in the column (15 days) caused the disruption of up to 92% of the original QDs and the immobilization of NPs and metals. These results indicate that QDs will accumulate in top-soils, where transformations phenomena will determine the overall transport, persistency and degradation of these chemicals. Once accumulated, they may act as a source for potentially toxic Cd and Se metal species displaying enhanced mobility.


Assuntos
Pontos Quânticos , Poluentes do Solo/análise , Compostos de Cádmio/química , Ecossistema , Ligantes , Nanopartículas , Compostos de Selênio/química , Solo/química , Sulfetos , Compostos de Zinco
5.
J Mycol Med ; 30(2): 100938, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32111505

RESUMO

Onychomycosis are fungal nail infections comprising of about 50% of onychopathies and are commonly caused by dermatophytes. The treatment of this dermatomycosis requires a long period of time and is associated with high rates of recurrence. In view of the need to evaluate the antifungal performance of promising preclinical compounds, we developed, in this study, a practical and accessibleex vivo model for establishing a Trichophyton rubrum onychomycosis framework using porcine hooves. This model has as its main advantage the similar structural and three-dimensional characteristics that the porcine hooves have with the human nail. The proposed model allowed to evaluate the antifungal activity of a new antifungal compound and a reference drug (terbinafine), both already incorporated into a nail lacquer for topical use. Treatments with compound 3-selenocyanate-indole (Se4a) and with terbinafine incorporated into this nail lacquer completely inhibited fungal growth, corresponding to the profile of in vitro activity observed against T. rubrum. This study concludes that the ex vivo porcine hoof model is an effective alternative method for preclinical screening of drugs or new topical compounds developed to combat onychomycosis. Further studies are needed to compare the permeability of porcine hooves with human nails permeability.


Assuntos
Antifúngicos/administração & dosagem , Avaliação Pré-Clínica de Medicamentos/métodos , Casco e Garras/patologia , Onicomicose/tratamento farmacológico , Técnicas de Cultura de Órgãos , Suínos , Administração Tópica , Animais , Antifúngicos/farmacologia , Cianatos/química , Casco e Garras/efeitos dos fármacos , Humanos , Laca , Testes de Sensibilidade Microbiana/métodos , Modelos Biológicos , Onicomicose/patologia , Permeabilidade/efeitos dos fármacos , Compostos de Selênio/química , Terbinafina/administração & dosagem , Terbinafina/farmacologia , Trichophyton/efeitos dos fármacos , Trichophyton/crescimento & desenvolvimento
6.
J Vis Exp ; (157)2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32202534

RESUMO

Developments in photovoltaic device architectures are necessary to make solar energy a cost-effective and reliable source of renewable energy amidst growing global energy demands and climate change. Thin film CdTe technology has demonstrated cost-competitiveness and increasing efficiencies due partially to rapid fabrication times, minimal material usage, and introduction of a CdSeTe alloy into a ~3 µm absorber layer. This work presents the close-space sublimation fabrication of thin, 1.5 µm CdSeTe/CdTe bilayer devices using an automated in-line vacuum deposition system. The thin bilayer structure and fabrication technique minimize deposition time, increase device efficiency, and facilitate future thin absorber-based device architecture development. Three fabrication parameters appear to be the most impactful for optimizing thin CdSeTe/CdTe absorber devices: substrate preheat temperature, CdSeTe:CdTe thickness ratio, and CdCl2 passivation. For proper sublimation of the CdSeTe, the substrate temperature prior to deposition must be ~540 °C (higher than that for CdTe) as controlled by dwell time in a preheat source. Variation in the CdSeTe:CdTe thickness ratio reveals a strong dependence of device performance on this ratio. The optimal absorber thicknesses are 0.5 µm CdSeTe/1.0 µm CdTe, and non-optimized thickness ratios reduce efficiency through back-barrier effects. Thin absorbers are sensitive to CdCl2 passivation variation; a much less aggressive CdCl2 treatment (compared to thicker absorbers) regarding both temperature and time yields optimal device performance. With optimized fabrication conditions, CdSeTe/CdTe increases device short-circuit current density and photoluminescence intensity compared to single-absorber CdTe. Additionally, an in-line close-space sublimation vacuum deposition system offers material and time reduction, scalability, and attainability of future ultra-thin absorber architectures.


Assuntos
Compostos de Cádmio/química , Eletricidade , Luminescência , Compostos de Selênio/química , Energia Solar , Sublimação Química , Telúrio/química , Automação , Metais/química , Temperatura , Vácuo , Volatilização
7.
J Photochem Photobiol B ; 204: 111799, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32018156

RESUMO

CdSe/CdS core shelled quantum dots (QDs) were prepared by colloidal synthesis using a binary ligand system and a non-coordinating, reusable solvent n-octadecane (nOD). Both the synthesis of CdSe and CdSe/CdS core shelled quantum dots were achieved by hot injection technique at much lower temperatures than reported earlier. The use of binary ligand facilitated enough nucleation and growth. Red shift in absorption spectra, an enhanced crystallite and particle size is evidenced by XRD and TEM respectively, confirming the formation of core shell structure of CdSe/CdS. The synthesized core shells exhibited high fluorescence intensity, long term stability and good mono dispersion, making it a potential material for bio-imaging and sensing. Core shell QDs were modified with mercapto propionic acid (MPA) to impart aqueous solubility. Studies on cytotoxicity of shelled QDs reveal good bio compatibility with a very minimum toxicity of IC50 = 20 µg/L. These QDs were used for sensing E. coli. Ordinary glass slide, modified using plasma etching is surface modified through APTES aiding conjugation of antibodies. Anti- E. coli polyclonal antibody on glass matrix (slide) and antibody conjugated QDs were used for detection of E. coli in a typical sandwich model. The excellent optical transparency of glass and high emission of QDs lead to detection of E.coli with a limit of detection of 50 CFU/mL.


Assuntos
Escherichia coli/efeitos dos fármacos , Vidro/química , Pontos Quânticos/química , Animais , Compostos de Cádmio/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Camundongos , Microscopia de Fluorescência , Pontos Quânticos/toxicidade , Compostos de Selênio/química , Sulfetos/química , Propriedades de Superfície
8.
Mikrochim Acta ; 187(2): 104, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31912290

RESUMO

Authors report on a new fluoro-graphene-plasmonic nanohybrid aptamer-based fluorescent nanoprobe for cocaine. To construct the nanoprobe, newly synthesized glutathione-capped ZnS/Ag2Se quantum dots (QDs) were first conjugated to graphene oxide (GO) to form a QD-GO nanocomposite. The binding interaction resulted in a fluorescence turn-ON. Thereafter, cetyltrimethylammonium bromide (CTAB)-gold nanoparticles (AuNPs) were directly adsorbed on the QD-GO nanocomposite to form a novel QD-GO-CTAB-AuNP nanohybrid assembly that resulted in a fluorescence turn-OFF. Streptavidin (strep) was then adsorbed on the QDs-GO-CTAB-AuNP nanohybrid assembly which allowed binding to a biotinylated MNS 4.1 anticocaine DNA aptamer (B) receptor. The addition of cocaine into the strep-B-QDs-GO-CTAB-AuNP aptamer nanoprobe system aided affinity to the aptamer receptor and in turn turned on the fluorescence of the nanoprobe in a concentration-dependent manner. Under optimum experimental conditions, we found the strep-B-QD-GO-CTAB-AuNP to be far superior in its sensitivity to cocaine than the tested strep-B-QDs (no GO and CTAB-AuNPs), strep-B-QD-CTAB-AuNP (no GO) and strep-B-QD-GO (no CTAB-AuNP). In addition, the investigation of localized surface plasmon resonance (LSPR) amplified signal from tested plasmonic NPs shows that CTAB-AuNPs was far superior in amplifying the fluorescence signal of the nanoprobe. A detection limit of 4.6 nM (1.56 ng.mL-1), rapid response time (~2 min) and excellent selectivity against other drugs, substances and cocaine metabolites was achieved. The strep-B-QD-GO-CTAB-AuNP aptamer-based fluorescent nanoprobe was successfully applied for the determination of cocaine in seized adulterated cocaine samples. Graphical abstractSchematic representation of the streptavidin-biotin-quantum dot-graphene oxide-cetyltrimethylammonium bromide-gold nanoparticle aptamer-based fluorescent nanoprobe for cocaine.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Cocaína/análise , Pontos Quânticos/química , Compostos de Selênio/química , Compostos de Prata/química , Sulfetos/química , Compostos de Zinco/química , Inibidores da Captação de Dopamina/análise , Contaminação de Medicamentos , Corantes Fluorescentes/química , Glutationa/química , Ouro/química , Grafite/química , Drogas Ilícitas/análise , Limite de Detecção , Nanopartículas Metálicas/química , Nanocompostos/química , Espectrometria de Fluorescência/métodos
9.
Chemistry ; 26(22): 4952-4957, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-31960982

RESUMO

Despite their biological importance, post-translationally modified proteins are notoriously difficult to produce in a homogeneous fashion by using conventional expression systems. Chemical protein synthesis or semisynthesis offers a solution to this problem; however, traditional strategies often rely on sulfur-based chemistry that is incompatible with the presence of any cysteine residues in the target protein. To overcome these limitations, we present the design and synthesis of γ-selenolysine, a selenol-containing form of the commonly modified proteinogenic amino acid, lysine. The utility of γ-selenolysine is demonstrated with the traceless ligation of the small ubiquitin-like modifier protein, SUMO-1, to a peptide segment of human glucokinase. The resulting polypeptide is poised for native chemical ligation and chemoselective deselenization in the presence of unprotected cysteine residues. Selenolysine's straightforward synthesis and incorporation into synthetic peptides marks it as a universal handle for conjugating any ubiquitin-like modifying protein to its target.


Assuntos
Cisteína/química , Lisina/química , Peptídeos/química , Proteína SUMO-1/química , Compostos de Selênio/química , Aminoácidos , Humanos , Processamento de Proteína Pós-Traducional , Proteína SUMO-1/metabolismo , Enxofre/química
10.
Molecules ; 25(1)2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31947731

RESUMO

The original goal of this research was to study stereochemistry of selenium dihalides addition to cycloalkenes and properties of obtained products. Remarkable alkene-to-alkene and alkene-to-alkyne transfer reactions of selenium dibromide and PhSeBr were discovered during this research. The adducts of selenium dibromide with alkenes or cycloalkenes easily exchange SeBr2 with other unsaturated compounds, including acetylenes, at room temperature, in acetonitrile. Similar alkene-to-alkene and alkene-to-alkyne transfer reactions of the PhSeBr adducts with alkenes or cycloalkenes take place. The supposed reaction pathway includes the selenium group transfer from seleniranium species to alkenes or alkynes. It was found that the efficient SeBr2 and PhSeBr transfer reagents are Se(CH2CH2Br)2 and PhSeCH2CH2Br, which liberate ethylene, leading to a shift in equilibrium. The regioselective and stereoselective synthesis of bis(E-2-bromovinyl) selenides and unsymmetrical E-2-bromovinyl selenides was developed based on the SeBr2 and PhSeBr transfer reactions which proceeded with higher selectivity compared to analogous addition reactions of SeBr2 and PhSeBr to alkynes under the same conditions.


Assuntos
Alcenos/química , Alquinos/química , Brometos/química , Cicloparafinas/química , Compostos de Selênio/química , Catálise , Ciclização
11.
Chem Commun (Camb) ; 56(12): 1780-1783, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-31938791

RESUMO

Herein, we disclose the first set of unique selenium-containing SnAP reagents for the direct synthesis of C-substituted selenomorpholines and 1,4-selenazepanes, including their amino acid derivatives from commercially available aldehydes under mild conditions. These elusive N-unprotected heterocycles are not accessible by classical routes. Biological evaluation of these compounds revealed promising activities against clinically relevant fungal strains.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida parapsilosis/efeitos dos fármacos , Compostos de Selênio/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Compostos de Selênio/síntese química , Compostos de Selênio/química , Relação Estrutura-Atividade
12.
Spectrochim Acta A Mol Biomol Spectrosc ; 229: 117962, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31865104

RESUMO

ZnS quantum dots (QDs) and their core/shell (CdSe/ZnS) structures were studied for Zn based precursor reactivities. ZnS and CdSe/ZnS QDs were prepared selecting aqueous route and then characterized via XRD, TEM, EDX, PL, RAMAN and FTIR practices. Core/shell nanostructures were synthesized by taking dissimilar precursors for the shell formation. Photoluminescence spectra of prepared QDs corroborate the effectual luminescence. Prepared QDs have large surface area that make them useful alternative as organic antimicrobial agent which are highly irritant and unstable. Study of antimicrobial behavior of QD structures was carried out by disk diffusion method. Antimicrobial study of QDs and their core/shell structures was performed against gram negative and gram positive bacteria, E. coli, A. baumanni and Bacillus subtilis respectively. It is found that elemental composition and size of QDs plays important role in antimicrobial behavior. Prepared QDs are fluorescent and have a key role in complex microbial population studies and identification of bacteria.


Assuntos
Anti-Infecciosos/farmacologia , Compostos de Cádmio/farmacologia , Luminescência , Pontos Quânticos/química , Compostos de Selênio/farmacologia , Sulfetos/farmacologia , Compostos de Zinco/farmacologia , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Compostos de Cádmio/química , Testes de Sensibilidade Microbiana , Pontos Quânticos/ultraestrutura , Compostos de Selênio/química , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Sulfetos/química , Difração de Raios X , Compostos de Zinco/química
13.
Talanta ; 206: 120228, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514892

RESUMO

The asymmetric flow field-flow fractionation (AF4) coupled on-line with elemental (inductively coupled plasma-mass spectrometry, ICP-MS) and molecular (fluorescence and UV) detection has been investigated as a powerful tool for the characterization of bioinorganic nano-conjugates. In this study, we described methods for the characterization of biotin-antibody complexes bioconjugated with streptavidin quantum dots (QDs-SA-b-Ab). Operating parameters of AF4 separation technique were optimized and two procedures are proposed using a channel thickness of 350 µm and 500 µm. The use of a 500 µm spacer allowed to achieve an efficient AF4 separation of the QDs-SA-b-Ab complexes from the excess of individual species used in the bioconjugation that was required for a proper characterization of the bioconjugates. Optimization of the AF4 allowed a separation resolution good enough to isolate the QDs-SA-b-Ab bioconjugates from the free excess of b-Ab and QD-SA. The efficiency of the bioconjugation process could be then calculated, obtaining a value of 86% for a 1 QDs-SA: 5 b-Ab bioconjugation ratio. In addition, sample recovery around 90% was achieved.


Assuntos
Pontos Quânticos/análise , Água/química , Anticorpos/química , Biotina/química , Compostos de Cádmio/análise , Compostos de Cádmio/química , Fluorescência , Fracionamento por Campo e Fluxo/métodos , Limite de Detecção , Espectrometria de Massas/métodos , Pontos Quânticos/química , Espalhamento de Radiação , Compostos de Selênio/análise , Compostos de Selênio/química , Estreptavidina/química , Sulfetos/análise , Sulfetos/química , Compostos de Zinco/análise , Compostos de Zinco/química
14.
Mater Sci Eng C Mater Biol Appl ; 106: 110181, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753367

RESUMO

I-III-VI chalcopyrite ternary quantum dots have emerged as a good alternative over the conventional II-VI and IV-VI chalcogenide binary QDs that usually consist of heavy metals such as Cd and Pb which has limited their bioapplications. Among the chalcopyrite QDs, AgInSe2 QDs has been the least developed due to the imbalanced cation reactivity, unwanted impurities, broad size distribution and resultant large particle sizes. In addition, the cell viability of these QDs still needs to be investigated on different cell lines both normal and cancerous ones. Herein, large-scale synthesis of water-soluble thioglycolic acid (TGA) capped and gelatin-stabilized AgInSe2 (AISe) core and AgInSe2/ZnSe (AISe/ZnSe) core/shell QDs in the absence of an inert atmosphere and their cell viability against different cell lines are reported. The optical and structural characteristics of the as-synthesized QDs were investigated by UV-visible (vis) absorption, photoluminescence (PL) and Fourier-transmission infrared (FTIR) spectroscopies, dynamic light scattering (DLS), X-ray diffraction (XRD), and high-resolution transmission electron microscope (HRTEM) techniques. Growth of ZnSe shell on the core AISe resulted in the blue shifting of the emission maximum position with the increased PL intensity. The QDs are small and spherical in shape with an average particle diameter of 2.8 nm and 3.2 nm for AISe and AISe/ZnSe QDs respectively. The in vitro cell viability assay revealed that the as-synthesized AISe/ZnSe QDs are not toxic towards cancerous (HeLa -cervical cancer and A549-lung cancer) and normal (BHK21 -Kidney) cell lines.


Assuntos
Pontos Quânticos/química , Tioglicolatos/química , Água/química , Sobrevivência Celular/fisiologia , Difusão Dinâmica da Luz , Humanos , Compostos de Selênio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Compostos de Zinco/química
15.
Anal Chim Acta ; 1093: 35-42, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31735213

RESUMO

In this study, cobalt-iron selenides embedded in porous carbon nanofibers (CoFe2Se4/PCF), derived from Prussian blue analogues, was prepared as a novel phenolic sensor. The obtained CoFe2Se4/PCF nanocomposites show three-dimensional (3D) networks nanostructures that can supply a desirable conductive network to accelerate electron transfer and avoid the aggregation of CoFe2Se4 nanoparticles. Electrochemical detection of hydroquinone (HQ), catechol (CC) and resorcinol (RS), at CoFe2Se4/PCF modified glassy carbon electrode (GCE) were researched. The results show the obtained 3D CoFe2Se4/PCF/GCE exhibits excellent electrochemical properties towards the simultaneous testing trace of HQ, CC and RS. The obtained electrode provides wide linear ranges of 0.5-200, 0.5-190 and 5-350 µM and low detection limit of 0.13, 0.15 and 1.36 µM for HQ, CC and RS, respectively. The as-prepared phenolic sensor displays satisfied selectivity and long-term storage stability. In addition, the constructed sensor can be used to determine HQ, CC and RS in actual samples.


Assuntos
Carbono/química , Catecóis/análise , Hidroquinonas/análise , Nanofibras/química , Resorcinóis/análise , Compostos de Selênio/química , Resinas Acrílicas/química , Catálise , Cobalto/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Compostos de Ferro/química , Lagos/análise , Limite de Detecção , Porosidade , Poluentes Químicos da Água/análise
16.
Anal Chim Acta ; 1096: 61-68, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31883592

RESUMO

Sensitive and reliable detection of biomarkers is of vital importance in tumor early detection and clinical therapy. A novel fluorescent/electrochemical dual-responsive immunosensing platform for reliable and sensitive quantification of biomarkers was designed based on cation-exchange reaction. To construct such a versatile platform, the model analyte, carcinoembryonic antigen (CEA), was captured by magnetic Fe3O4 nanoparticles bound with primary antibodies (Fe3O4-Ab1) and then recognized by the detection antibodies conjugated complex containing poly(amidoamine) (PAMAM), carbon nanotube (CNT) and carboxyl functionalized CdSe nanocrystals (NCs) (CNT-PAMAM-CdSe NCs-Ab2). Via ligand exchange, the stable CdSe nanocrystals were easily functionalized with carboxylate ion (CdSe-COO-) and showed high hydrophilicity. The CdSe-COO- was effectively and densely conjugated to CNT coated dendrimer PAMAM that possesses large specific surface area. Finally, the target CEA was detected based on cation-exchange reaction (CER) by adding Ag+ to release thousands of cations Cd2+, which were detected by fluorescence and electrochemistry simultaneously. The electrochemical measurement was performed by directly detecting Cd2+ through square wave voltammetry (SWV), which displayed an excellent correlation with CEA from 5 pg/mL to 50 ng/mL, with a limit of detection (LOD) of 1.7 pg/mL. The fluorescence detection was implemented since free Cd2+ could trigger the weak fluorescence metal-sensitive dyes (Rhod-5N) to generate extremely high fluorescence signal. The fluorescence results showed the LOD for CEA detection was 0.25 pg/mL with a calibration curve range from 1 pg/mL to 20 ng/mL. The dual signal outputs showed an attractively self-correcting ability, which provides the capability of avoiding false positive signal and making the detection result more reliable. The proposed dual-responsive platform holds great promises for biomarkers detection in clinical diagnostics and therapy.


Assuntos
Anticorpos Imobilizados/química , Técnicas Biossensoriais/métodos , Compostos de Cádmio/química , Antígeno Carcinoembrionário/sangue , Nanopartículas/química , Compostos de Selênio/química , Antígeno Carcinoembrionário/análise , Cátions/química , Dendrímeros/química , Técnicas Eletroquímicas/métodos , Corantes Fluorescentes/química , Humanos , Imunoensaio/métodos , Limite de Detecção , Nanopartículas de Magnetita/química , Nanotubos de Carbono/química , Espectrometria de Fluorescência/métodos
17.
Talanta ; 208: 120430, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816682

RESUMO

Early detection of cancer increases the possibility for an adequate and successful treatment of the disease. Therefore, in this work, a disposable electrochemical immunosensor for the front-line detection of the ExtraCellular Domain of the Human Epidermal growth factor Receptor 2 (HER2-ECD), a breast cancer biomarker, in a simple and efficient manner is presented. Bare screen-printed carbon electrodes were selected as the transducer onto which a sandwich immunoassay was developed. The affinity process was detected through the use of an electroactive label, core/shell CdSe@ZnS Quantum Dots, by differential pulse anodic stripping voltammetry in a total time assay of 2 h, with an actual hands-on time of less than 30 min. The proposed immunosensor responded linearly to HER2-ECD concentration within a wide range (10-150 ng/mL), showing acceptable precision and a limit of detection (2.1 ng/mL, corresponding to a detected amount (sample volume = 40 µL) of 1.18 fmol) which is about 7 times lower than the established cut-off value (15 ng/mL). The usefulness of the developed methodology was tested through the analysis of spiked human serum samples. The reliability of the presented biosensor for the selective screening of HER2-ECD was confirmed by analysing another breast cancer biomarker (CA15-3) and several human serum proteins.


Assuntos
Biomarcadores Tumorais/sangue , Neoplasias da Mama/sangue , Receptor ErbB-2/sangue , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Antígenos/química , Antígenos/imunologia , Compostos de Cádmio/química , Técnicas Eletroquímicas , Humanos , Imunoensaio , Imunoglobulina G/química , Imunoglobulina G/imunologia , Masculino , Pontos Quânticos/química , Receptor ErbB-2/imunologia , Compostos de Selênio/química , Soroalbumina Bovina/química , Soroalbumina Bovina/imunologia , Sulfetos/química , Compostos de Zinco/química
18.
Biosens Bioelectron ; 147: 111786, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654824

RESUMO

Herein, a new "on-off-on" signal switch system combined triple helix molecular switch with efficient charge separation and transfer between different sensitization units was designed for the ultrasensitive photoelectrochemical (PEC) determination of prostate-specific antigen (PSA). Concretely, the initial "signal-on" state was obtained via the cascaded sensitization structure consisting of type-II CdTe@CdSe core-shell quantum dots (QDs), CdS QDs, and ZnO nanotubes, which were assembled on Au nanoparticles modified paper fibers with the aid of signal transduction probe (STP). Thereinto, the type-II CdTe@CdSe QDs with hole-localizing core and electron-localizing shell could enable the ultrafast charge transfer and retard the charge recombination, magnifying the initial photocurrent response and preserving the high efficiency of signal-switchable PEC aptasensing system. Subsequently, the PSA aptamer (PSA-Apt) modified with gold nanoparticles (GNPs) was introduced by the hybridization of PSA-Apt with STP and the hairpin configuration of STP changed from closed to open state, forming a triple-helix structure. Hence, the CdTe@CdSe QDs labeled on the terminal of STP moved away from the electrode surface while the GNPs kept attached close to it. The proposed aptasensor turned to "signal-off" state because of the dual inhibition of vanished cosensitization effect and signal quenching effect of GNPs. Upon the target recognition, the triple-helix structure was perturbed with the formation of DNA-protein complex and the recovery of STP hairpin structure, resulting in the second "switch-on" state. Based on the target-induced photocurrent enhancement, the proposed PEC aptasensor was utilized for the determination of PSA with high sensitivity, persuasive selectivity, and excellent stability.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Complexos Multiproteicos/isolamento & purificação , Antígeno Prostático Específico/isolamento & purificação , Aptâmeros de Nucleotídeos/química , Compostos de Cádmio/química , Sistemas de Liberação de Medicamentos , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Complexos Multiproteicos/química , Nanotubos/química , Pontos Quânticos/química , Compostos de Selênio/química
19.
Eur J Med Chem ; 185: 111811, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31693947

RESUMO

Functionalised aliphatic selenols, straightforwardly obtained through ring-opening reaction of strained heterocycles, represent a new chemotype acting as carbonic anhydrase inhibitors (CAIs). These compounds showed pronounced selectivity towards the cytosolic human (h) isoforms such as the hCA I, II and VII rather than the membrane tumor associate hCA IX. In addition, we reported for the first time the X-ray crystal structure of an aliphatic selenol bound to the hCA I zinc ion, and that afforded the opportunity to decipher in detail the inhibition mechanism underpinning such a new class of CAIs. In this context selenols are interesting leads worth developing for the obtainment of novel and efficient selective CAIs potentially useful for the management of a variety of diseases including glaucoma, retinitis pigmentosa, epilepsy and arthritis.


Assuntos
Anidrase Carbônica II/antagonistas & inibidores , Anidrase Carbônica IX/antagonistas & inibidores , Anidrase Carbônica I/antagonistas & inibidores , Inibidores da Anidrase Carbônica/farmacologia , Compostos de Selênio/farmacologia , Sítios de Ligação/efeitos dos fármacos , Anidrase Carbônica I/metabolismo , Anidrase Carbônica II/metabolismo , Anidrase Carbônica IX/metabolismo , Inibidores da Anidrase Carbônica/síntese química , Inibidores da Anidrase Carbônica/química , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Humanos , Modelos Moleculares , Estrutura Molecular , Compostos de Selênio/síntese química , Compostos de Selênio/química , Relação Estrutura-Atividade
20.
Mikrochim Acta ; 187(1): 10, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797114

RESUMO

A lateral-flow immunochromatographic assay with excellent sensitivity and wide application potential is described. The bovine serum albumin (BSA) antibody was immobilized in the test line for universality, and preincubation was introduced for high method sensitivity. Carboxy-modified CdSe/ZnS core-shell nanoparticles were used as label, and the fluorescence peaking at 605 nm was detected. The fluorescence in the test line was negative against the relevant analyte content. The chloramphenicol (CAP) and the aflatoxin M1 (AFM1) in milk were detected using the same strip to validate the universality. After optimization, the detection limit for CAP is 10 pg·mL-1, which is three times less that of a conventional assay (30 pg·mL-1). The detection limit for AFM1 was 6 pg·mL-1, which was 13 times less than that of a conventional assay (8 pg·mL-1). The method was applied in the analysis of spiked milk samples. The performance was compared with that of the commercial ELISA kit, and good agreement was observed. Graphical abstractSchematic representation of the universal and sensitive combined immunochromatographic assay (USICA) and conventional immunochromatographic assay (TICA) of chloramphenicol (CAP) and aflatoxin M1.


Assuntos
Aflatoxina M1/análise , Anticorpos Imobilizados/química , Compostos de Cádmio/química , Cloranfenicol/análise , Imunoensaio/métodos , Nanopartículas/química , Compostos de Selênio/química , Sulfetos/química , Compostos de Zinco/química , Aflatoxina M1/química , Anticorpos Imobilizados/imunologia , Cloranfenicol/química , Limite de Detecção , Soroalbumina Bovina/imunologia
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