Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.810
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Chem Commun (Camb) ; 56(18): 2691-2694, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32051985

RESUMO

A conductive polymer thin film having choline phosphate as the side group was prepared. Quartz crystal microbalance (QCM) was employed to evaluate the adsorption of the model protein, bovine serum albumin (BSA), on the films deposited on indium tin oxide (ITO) electrodes. Cell adsorption on the film was evaluated by a fibroblast NIH3T3.


Assuntos
Fosforilcolina/química , Polímeros/química , Soroalbumina Bovina/química , Adsorção , Animais , Bovinos , Condutividade Elétrica , Eletrodos , Camundongos , Estrutura Molecular , Células NIH 3T3 , Imagem Óptica , Polímeros/síntese química , Técnicas de Microbalança de Cristal de Quartzo , Propriedades de Superfície , Compostos de Estanho/química
2.
Chem Commun (Camb) ; 56(10): 1513-1516, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31919482

RESUMO

A potentiometric resolved photoelectrochemical (PEC) system based on CdS nanowires and SnNb2O6 nanosheets was developed. To prove the applicability of this system in PEC multi-biomarker analysis, a label free PEC immunosensor for two cardiac biomarkers, myoglobin and cardiac troponin I, was constructed.


Assuntos
Biomarcadores/análise , Técnicas Eletroquímicas/métodos , Nanoestruturas/química , Nanofios/química , Compostos de Estanho/química , Técnicas Biossensoriais , Compostos de Cádmio/química , Humanos , Mioglobina/análise , Sulfetos/química , Troponina I/análise
3.
Chemosphere ; 241: 125115, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683419

RESUMO

In this study, a novel and highly reactive Sn-Pd catalyst supported by environmentally benign kaolinite (Sn-Pd-kaolinite) was developed and evaluated for stability for effective nitrate (NO3-) reduction in batch and continuous mode. Complete NO3- removal with fast reduction kinetics (k = 18.16 × 10-2 min-1) and 71% selectivity toward N2 were achieved by the Sn-Pd-kaolinite catalyst during batch reactions. During continuous tests, 100% NO3- removal and 80% N2 was achieved for 60 h. However, NO3- removal efficiency gradually decreased to 80% in170 h. The catalyst was then successfully regenerated in the system by increasing H2 flow which achieved a complete NO3- removal again. The metal leaching from catalyst surface was negligible (Sn 0.01% and Pd 0.006%) and the structure was stable during the continuous test, confirming that the Sn-Pd-Kaolinite catalyst had a superior reaction kinetics and operational durability.


Assuntos
Temperatura Alta , Caulim/química , Nitratos/química , Compostos de Estanho/química , Catálise , Cinética , Oxirredução , Paládio/química
4.
Chemosphere ; 241: 125103, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683438

RESUMO

In this paper, a novel electrode named 2.5D Ti/Sb-SnO2/PANI was developed by magnetically in-situ integration of adsorbent and electrocatalyst, where the green synthetic Fe3O4/polyaniline (PANI) nanoparticles with fair adsorption capability were used as auxiliary electrodes and coated on the surface of Ti/Sb-SnO2 main electrode, to enrich the pollutants in the vicinity of anode and therefore boost the electrochemical oxidation (EO) efficiency. Since the interchangeable auxiliary electrodes can endow the anode with adjustability and versatility, the effect of auxiliary electrodes on the surface structure and electrochemical properties of 2.5D Ti/Sb-SnO2/PANI were extensively investigated. Results showed that a tiny amount of Fe3O4/PANI auxiliary electrodes changed the solid-liquid interface, brought massive less acessible active sites and kept the similar electrode impedance and same EO capability of 2D Ti/Sb-SnO2. In terms of organic elimination and solution biodegradability enhancement, 2.5D Ti/Sb-SnO2/PANI showed a boosted 30%-60% EO efficiency on two typical biorefractory targets, i.e., Acid Red G and lignosulphonate. The specific effectiveness was dependent on the loading amount of magenetic PANI nanoparticles. The operating mechanism of the assembled 2.5D Ti/Sb-SnO2/PANI electrode was further proposed based on many details, as well as a design rule for developing novel electrodes with high efficient EO performance for wastewater treatment. Moreover, the assembled 2.5D electrode was proved to have good sustainability and recyclability, which shows a great potential in the practical applications.


Assuntos
Técnicas Eletroquímicas/métodos , Eletrodos/normas , Nanopartículas/química , Águas Residuárias/química , Purificação da Água/métodos , Compostos de Anilina , Catálise , Magnetismo/métodos , Oxirredução , Compostos de Estanho/química , Titânio/química
5.
Chemosphere ; 239: 124715, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31499311

RESUMO

Electrodeposition is an economical and efficient way to prepare Ti/SnO2-Sb electrode for electrochemical oxidizing pollutants in wastewater. The solvent used for electrodeposition has a great effect on electrode performance. The conventional Ti/SnO2-Sb electrode electrodeposited using aqueous solvent has poor electrochemical activity and short service life. In this study, a Ti/SnO2-Sb electrode was prepared via electrodeposition using a deep eutectic solvent (DES). This new Ti/SnO2-Sb-DES electrode performed a rate constant of 0.571 h-1 for methylene blue decolorization and long accelerated service life of 12.9 h (100 mA cm-2; 0.5 M H2SO4), which were 1.7 times and 3.2 times as high as that of the electrode prepared in aqueous solvent, respectively. The enhanced properties were related to the 1.3 times increased electrochemically active surface area of Ti/SnO2-Sb-DES electrode which had a rough, multilayer and uniform surface structure packed with nano-sized coating particles. In conclusion, this study developed a facile, green and efficient pathway to prepare Ti/SnO2-Sb electrode with high performance.


Assuntos
Antimônio/química , Técnicas Eletroquímicas/métodos , Galvanoplastia/métodos , Solventes/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Eletrodos/normas , Azul de Metileno/química , Oxirredução , Compostos de Estanho/química , Titânio/química , Águas Residuárias/química
6.
Nanotechnology ; 31(5): 055501, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31484166

RESUMO

Humidity sensors based on flexible sensitive nanomaterials are very attractive in noncontact healthcare monitoring. However, the existing humidity sensors have some shortcomings such as limited sensitivity, narrow relative humidity (RH) range, and a complex process. Herein, we show that a tin sulphide (SnS) nanoflakes-based sensor presents high humidity sensing behaviour both in rigid and flexible substrate. The sensing mechanism based on the Schottky nature of a SnS-metal contact endows the as-fabricated sensor with a high response of 2491000% towards a wide RH range from 3% RH to 99% RH. The response and recovery time of the sensor are 6 s and 4 s, respectively. Besides, the flexible SnS nanoflakes-based humidity sensor with a polyimide substrate can be well attached to the skin and exhibits stable humidity sensing performance in the natural flat state and under bending loading. Moreover, the first-principles analysis is performed to prove the high specificity of SnS to the moisture (H2O) in the air. Benefiting from its promising advantages, we explore some application of the SnS nanoflakes-based sensors in detection of breathing patterns and non-contact finger tips sensing behaviour. The sensor can monitor the respiration pattern of a human being accurately, and recognize the movement of the fingertip speedily. This novel humidity sensor shows great promising application in physiological and physical monitoring, portable diagnosis system, and noncontact interface localization.


Assuntos
Técnicas Biossensoriais/instrumentação , Umidade , Nanoestruturas/química , Sulfetos/química , Compostos de Estanho/química , Água/química , Humanos , Monitorização Ambulatorial/instrumentação , Nanoestruturas/ultraestrutura , Tempo de Reação , Dióxido de Silício/química , Propriedades de Superfície
7.
J Pharm Biomed Anal ; 177: 112832, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31473480

RESUMO

Recently, self-assembled monolayers (SAMs) are gaining a lot of interest due to their simplicity of preparation and wide applicability in the development of model systems used in pharmaceutical and biomedical analysis. The most efficient methods used for the investigation of SAM-based structures usually include cyclic voltammetry and electrochemical impedance spectroscopy. Scanning electrochemical microscopy (SECM) could be also used as an alternative method for SAM investigations, because this method enables to map modified surface. In this work, the surface of fluorine doped tin oxide (FTO) was modified with octadeciltrichlorosilane (OTS) based SAM and investigated using SECM. Measurements, which were carried out by SECM, lead to conclusion that highly heterogeneous and distributed monolayer has been formed on FTO surface.


Assuntos
Química Farmacêutica/instrumentação , Flúor/química , Silanos/química , Compostos de Estanho/química , Técnicas Biossensoriais/instrumentação , Eletrodos , Microscopia Eletroquímica de Varredura , Propriedades de Superfície
8.
Photochem Photobiol Sci ; 18(12): 2989-2999, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31763667

RESUMO

Multifunctional SnO2/TiO2/RGO nanocomposites with enhanced photocatalytic degradation and antibacterial activity have been successfully synthesized by a facile one-pot environmentally friendly green hydrothermal route using titanium tetrabutoxide (TBOT), Na2SnO3 and graphene oxide (GO) without reducing agents and any structure-directing agents. The results demonstrate that the reaction pH conditions play important roles in the control of the crystallographic phases of TiO2 and SnO2. In addition, the visible-light-active photocatalytic and antibacterial activities of the synthesized composites were measured for the degradation of rhodamine B (RhB) and the growth inhibition of the Gram-negative bacteria Escherichia coli (E. coli), which are strongly affected by the SnO2 loading content, the crystal structure of TiO2 and the appropriate addition of graphene. The superior photocatalytic and antibacterial activities of the nanocomposites were attributed to their great optical adsorption capability and excellent charge separation and transfer efficiency. This study may provide new insights into the fabrication of efficient visible-light-active SnO2/TiO2/RGO nanocomposites and expand their applications in the environmental remediation and water disinfection fields.


Assuntos
Antibacterianos/química , Grafite/química , Luz , Nanocompostos/química , Compostos de Estanho/química , Titânio/química , Antibacterianos/farmacologia , Catálise , Escherichia coli/efeitos dos fármacos , Nanocompostos/toxicidade , Fotólise/efeitos da radiação , Rodaminas/química
9.
Environ Int ; 133(Pt A): 105157, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31520959

RESUMO

Electrochemical degradation of trace antiretroviral drug stavudine was investigated by using a reactive electrochemical membrane (REM) with Ti/SnO2-Sb anode. From the results it was evident that the stavudine degradation followed pseudo-first-order kinetics, with the values of the degradation rate constant and half-life being 0.24 min-1 and 2.9 min, respectively, at a current density of 8 mA cm-2. The degradation rate was obviously decreased under alkaline condition (pH = 11.0) and the degradation was also inhibited in the presence of NO3- and Cl-. Five intermediates were identified in the electrochemical degradation of stavudine, and the degradation pathways were proposed. Density functional theory calculation revealed that the double bond carbon atom nearby hydroxymethyl group was the site attacked by OH and the cleavage of CN bond was the rate-determining step in the electrochemical degradation of stavudine. The nitrogen in stavudine was mainly converted to nitrate and ammonium. Quantitative structure-activity relationship model indicated that the toxicity of some intermediates was higher than the parent compound stavudine. The electric energy consumption for 90% stavudine degradation ranged from 0.87 to 2.29 Wh L-1 at the experimental conditions, indicating that stavudine can be degraded efficiently by the REM with Ti/SnO2-Sb anode.


Assuntos
Antimônio/química , Antivirais/isolamento & purificação , Estavudina/isolamento & purificação , Titânio/química , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Eletrodos , Oxirredução , Porosidade , Compostos de Estanho/química
10.
Biosensors (Basel) ; 9(3)2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31546934

RESUMO

We show a new type of elastic surface-enhanced Raman spectroscopy (SERS) platform made of poly(ethylene terephthalate) (PET) covered with a layer of indium tin oxide (ITO). This composite is subjected to dielectric barrier discharge (DBD) that develops the active surface of the PET/ITO foil. To enhance the Raman signal, a modified composite was covered with a thin layer of silver using the physical vapor deposition (PVD) technique. The SERS platform was used for measurements of para-mercaptobenzoic acid (p-MBA) and popular pesticides, i.e., Thiram and Carbaryl. The detection and identification of pesticides on the surface of fruits and vegetables is a crucial issue due to extensive use of those chemical substances for plant fungicide and insecticide protection. Therefore, the developed PET/ITO/Ag SERS platform was dedicated to quantitative analysis of selected pesticides, i.e., Thiram and Carbaryl from fruits. The presented SERS platform exhibits excellent enhancement and reproducibility of the Raman signal, which enables the trace analysis of these pesticides in the range up to their maximum residues limit. Based on the constructed calibration curves, the pesticide concentrations from the skin of apples was estimated as 2.5 µg/mL and 0.012 µg/mL for Thiram and Carbaryl, respectively. Additionally, the PET/ITO/Ag SERS platform satisfies other spectroscopic properties required for trace pesticide analysis e.g., ease, cost-effective method of preparation, and specially designed physical properties, especially flexibility and transparency, that broaden the sampling versatility to irregular surfaces.


Assuntos
Praguicidas/metabolismo , Análise Espectral Raman/métodos , Compostos de Estanho/química , Limite de Detecção , Praguicidas/análise
11.
Phys Chem Chem Phys ; 21(39): 21875-21881, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31553031

RESUMO

Controlled modification of the semiconductor surface work function is of fundamental importance for improvements in the efficiency of (opto-)electronic devices. Binding amino acids to a semiconductor surface through their common carboxylic group offers a versatile tool for modulation of surface properties by the choice of their side chain. This approach is demonstrated here by tailoring the surface work function of indium tin oxide, one of the most abundant transparent electrodes in organic optoelectronic devices. We find that the work function can be systematically tuned by the side chain of the amino acid, resulting in either an increase or a decrease of the work function, over a large range of ∼250 meV. This side chain effect is mostly due to alteration of the dipole component perpendicular to the surface, with a generally smaller contribution for changes in surface band bending. These findings also shed light on electronic interactions at the interface between proteins and semiconductors, which are of importance for future bio-electronic devices.


Assuntos
Aminoácidos/química , Compostos de Estanho/química , Adsorção , Técnicas Eletroquímicas/métodos , Eletrodos , Modelos Químicos , Conformação Molecular , Semicondutores , Relação Estrutura-Atividade , Propriedades de Superfície
12.
Molecules ; 24(15)2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31370316

RESUMO

Aluminum-doped tin oxide (SnO 2:Al) thin films were produced by an ultrasonic spray pyrolysis method. The effect of aluminum doping on structural, optical, and electrical properties of tin oxide thin films synthesized at 420 ∘C was investigated. Al doping induced a change in the morphology of tin oxide films and yielded films with smaller grain size. SnO 2 thin films undergo a structural reordering and have a texture transition from (301) to (101), and then to (002) preferred cristallographic orientation upon Al doping. The lattice parameters (a and c) decreases with Al doping, following in a first approximation Vegard's law. The optical transmission does not change in the visible region with an average transmittance value of 72-81%. Conversely, in the near infrared (NIR) region, the plasmon frequency shifts towards the IR region upon increasing Al concentration in the grown films. Nominally undoped SnO 2 have a conductivity of ∼1120 S/cm, which is at least two orders of magnitude larger than what is reported in literature. This higher conductivity is attributed to the Cl- ions in the SnCl 4.5(H 2 O) precursor, which would act as donor dopants. The introduction of Al into the SnO 2 lattice showed a decrease of the electrical conductivity of SnO 2 due to compensating hole generation. These findings will be useful for further studied tackling the tailoring of the properties of highly demanded fluorine doped tin oxide (FTO) films.


Assuntos
Alumínio/química , Pirólise , Compostos de Estanho/química , Óxido de Zinco/química , Condutividade Elétrica , Índio/química , Espectrometria por Raios X , Compostos de Estanho/síntese química , Ultrassom
13.
Int J Nanomedicine ; 14: 5691-5696, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31413569

RESUMO

Background: Artificial intelligence (AI) integrated circuits (IC) have memory devices as the key component. Due to more complex algorithms and architectures required by neuroscience and other medical applications, various memory structures have been widely proposed and investigated by involving nanomaterials, such as memristors. Methods: Due to reliability issues of mass production, the dominant memory devices in many computers are still dynamic random access memory (DRAM). A DRAM has one transistor and one capacitor, and so it contains two devices and requires a more compact design to replace. Results: A one-transistor memory device which is more compact than DRAM is proposed. As far as the authors know, this is the first/novel flexible and transparent one-transistor memory device without any additional process to make a typical transistor and which is based on polyvinyl alcohol. By using indium-titanium-oxide (ITO) as the metal gate, PVA as the dielectric layer and In-Ga-Zn-O (IGZO) as the channel, the memory is implemented mainly based on amorphous oxides and transparent flexible nanomaterials. The charge storage for the memory function was investigated here and is attributed to the mechanism of charge trapping between the ITO/IGZO junctions. It shows typical artificial synaptic transmission behaviors such as EPSC (excitatory postsynaptic currents). Conclusion: Such a first flexible and transparent one-transistor memory device based on PVA has one capacitor less than DRAM and could be a potential and promising candidate as an alternative for DRAM, especially in the highly complex AI chips needed for numerous medical applications. The flexible memory nanodevice based on flexible dielectrics such as PVA, which shows typical memory and artificial synaptic behaviors, could also be suitable for portable, flexible, transparent or skin-like medical applications.


Assuntos
Inteligência Artificial , Nanoestruturas/química , Transistores Eletrônicos , Humanos , Reprodutibilidade dos Testes , Compostos de Estanho/química
14.
Chemistry ; 25(61): 14003-14009, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31469199

RESUMO

The systematic assembly of supramolecular arrangements is a persistent challenge in modern coordination chemistry, especially where further aspects of complexity are concerned, as in the case of large molecular mixed-metal arrangements. One targeted approach to such heterometallic complexes is to engineer metal-based donor ligands of the correct geometry to build 3D arrangements upon coordination to other metals. This simple idea has, however, only rarely been applied to main group metal-based ligand systems. Here, we show that the new, bench-stable tris(3-pyridyl)stannane ligand PhSn(3-Py)3 (3-Py=3-pyridyl) provides simple access to a range of heterometallic SnIV /transition metal complexes, and that the presence of weakly coordinating counter anions can be used to build discrete molecular arrangements involving anion encapsulation. This work therefore provides a building strategy in this area, which parallels that of supramolecular transition metal chemistry.


Assuntos
Complexos de Coordenação/química , Metais/química , Polímeros/química , Compostos de Estanho/química , Cristalografia por Raios X , Ligantes , Conformação Molecular , Estanho/química
15.
Colloids Surf B Biointerfaces ; 182: 110341, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31284148

RESUMO

In the present study, we fabricated a label-free avian influenza (AIV H5N1) detection biosensor composed of a multi-functional DNA 3 way-Junction (3 W J) on a hollow Au spike-like nanoparticle (hAuSN) using a localized surface plasmon resonance (LSPR) method. To construct the multi-functional DNA (MF-DNA) as a bioprobe, the 3 W J was introduced. The proposed AIV detection bioprobe should contain three functionalities: target recognition, signal amplification, and connection to substrate. To achieve this goal, each piece of the DNA 3 W J was tailored to a hemagglutinin (HA) binding aptamer, FAM dye and thiol group, respectively. The assembly of each DNA 3 W J functional fragment was then confirmed by TBM-Native PAGE. Moreover, the hAuSN was immobilized on the indium-tin-oxide (ITO) substrate for LSPR measurement. The DNA 3 W J was immobilized onto the hAuSN electrode through the thiol-group of DNA 3 W J. The fabricated DNA 3 W J/hAuSN heterolayer on the ITO substrate was investigated by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). LSPR experiments were conducted to confirm HA protein binding to the DNA 3 W J/ hAuSN -modified electrode. The proposed biosensor can detected the HA protein in PBS buffer (LOD: 1 pM) as well as in the diluted chicken serum (LOD: 1 pM). The present study details a label-free, simple fabrication method consisted of DNA 3 W J/ hAuSN heterolayer that uses easy-to-tailor elements to detect not only AIV but also various viruses detection platform easily.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/sangue , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/diagnóstico , Nanopartículas Metálicas/química , Animais , Galinhas , Eletrodos , Ouro/química , Influenza Aviária/sangue , Limite de Detecção , Nanopartículas Metálicas/ultraestrutura , Conformação de Ácido Nucleico , Ressonância de Plasmônio de Superfície , Compostos de Estanho/química
16.
J Synchrotron Radiat ; 26(Pt 4): 1245-1252, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31274450

RESUMO

The transparent conducting oxide, SnO2, is a promising optoelectronic material with predicted tailorable properties via pressure-mediated band gap opening. While such electronic properties are typically modeled assuming perfect crystallinity, disordering of the O sublattice under pressure is qualitatively known. Here a quantitative approach is thus employed, combining extended X-ray absorption fine-structure (EXAFS) spectroscopy with X-ray diffraction, to probe the extent of Sn-O bond anharmonicities in the high-pressure cubic (Pa\bar{3}) SnO2 - formed as a single phase and annealed by CO2 laser heating to 2648 ± 41 K at 44.5 GPa. This combinational study reveals and quantifies a large degree of disordering in the O sublattice, while the Sn lattice remains ordered. Moreover, this study describes implementation of direct laser heating of non-metallic samples by CO2 laser alongside EXAFS, and the high quality of data which may be achieved at high pressures in a diamond anvil cell when appropriate thermal annealing is applied.


Assuntos
Pressão , Compostos de Estanho/química , Difração de Raios X/métodos , Lasers , Espectroscopia por Absorção de Raios X/métodos
17.
Anal Chim Acta ; 1077: 129-139, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31307701

RESUMO

A comparative study was made by using two matrices (Linear poly(glycidyl methacrylate) (GMA) polymer (LP(GMA)) and carbon black-polyvinylidene fluoride (PVDF)-LP(GMA) composite CLP(GMA)) as immobilization platforms for anti-IL 1α antibody on the development of impedimetric immunosensor for IL 1α biomarker determination. These materials were spin coated onto the clean ITO electrode surface separately and used for IL 1α immunosensor fabrication. Carbon black is utilized as a conductive material and has been employed over the last few decades for electrochemical biosensors development. The using of CLP(GMA) composite as an interface material shows fast electron transfer, when compared to LP(GMA) modified ITO electrode. This comparative study investigated the efficacy of carbon black for impedimetric biosensing. Anti-IL 1α antibodies were utilized as bioreceptors and bound to epoxy groups of GMA polymer. For electrochemical characterizations, Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Single Frequency Impedance methods were employed. Furthermore, to follow the antibody attachment on the modified ITO substrates, Fourier Transform Infrared Spectroscopy and Raman spectral techniques were utilized. The morphological characterizations of immunosensor construction stages were carried out by Scanning Electron Microscopy and Atomic Force Microscopy analyses. The sensitive and label-free technique of EIS was used for quantification of IL 1α concentration. Under optimum experimental conditions, the immunosensor had a good linear relationship between impedance values and the IL 1α concentrations ranging from 0.01 to 2 pg/mL and from 0.01 to 3 pg/mL for LP(GMA) and CLP(GMA) modified ITO electrodes, respectively. The results confirmed that CLP(GMA) used in the preparation of the immunosensor illustrated improvements in immunosensor performance, comparing to the LP(GMA) modified immunosensor. Additionally, the immunosensor was successfully applied to evaluate human serum and saliva samples. The obtained results from these samples illustrated the feasibility of the immunosensor for clinical diagnosis in complex biological samples. Also, a simple and low-cost approach was attempted for development of immunosensor with remarkable performance characteristics.


Assuntos
Anticorpos Imobilizados/imunologia , Interleucina-1alfa/sangue , Ácidos Polimetacrílicos/química , Polivinil/química , Fuligem/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Imunoensaio/métodos , Interleucina-1alfa/imunologia , Limite de Detecção , Saliva/química , Compostos de Estanho/química
18.
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
19.
Analyst ; 144(15): 4661-4666, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31259991

RESUMO

A split-type photoelectrochemical immunosensor was designed for the ultrasensitive monitoring of prostate-specific antigen (PSA) based on a Cu2+-mediated catalytic reaction for inhibiting the in situ generation of CdS quantum dots (QDs) coupled with the enhancement of the CdS/MoS2 heterojunction; it was constructed by the stepwise modification of MoS2 QDs and CdS QDs onto an ITO electrode surface. In the presence of PSA, CuO NP-labeled anti-PSA antibodies were immobilized onto an anti-PSA antibody-modified 96-well plate via a sandwich immunoreaction and dissolution by hydrochloric acid to obtain a large number of Cu2+ ions. As the Cu2+-triggered catalytic oxidization of glutathione occurred, the in situ growth of CdS QDs as a signal indicator was significantly suppressed, resulting in reduction in the photocurrent response. Under optimal conditions, the biosensor exhibited desirable linearity in the range from 0.5 pg mL-1 to 10 ng mL-1, low detection limit of 0.29 pg mL-1, satisfactory selectivity, and good stability. It was applied to PSA detection in human serum, suggesting a great potential for early diagnostics of some cancers.


Assuntos
Cobre/química , Antígeno Prostático Específico/sangue , Pontos Quânticos/química , Anticorpos Imobilizados/imunologia , Técnicas Biossensoriais/métodos , Compostos de Cádmio/química , Compostos de Cádmio/efeitos da radiação , Dissulfetos/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Glutationa/química , Humanos , Imunoensaio/métodos , Luz , Limite de Detecção , Masculino , Molibdênio/química , Oxirredução , Processos Fotoquímicos , Antígeno Prostático Específico/imunologia , Pontos Quânticos/efeitos da radiação , Sulfetos/química , Sulfetos/efeitos da radiação , Compostos de Estanho/química
20.
Mikrochim Acta ; 186(7): 403, 2019 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-31183625

RESUMO

Antimony-doped tin oxide nanoparticles (ATO NPs) were loaded on a filter paper where they act as a peroxidase mimic without electrochemical or photochemical assistance. The peroxidase mimicking activity is distinctly improved compared to most known nanomaterials and to natural horseradish peroxidase. The catalytic properties depend on the amount of antimony doped into the ATO NPs. A glucose assay was worked out that is based on (a) the oxidation of glucose by glucose oxidase under formation of H2O2, (b) the oxidation of 3,3,5,5-tetramethybenzidine (TMB) catalyzed by ATO NPs to form blue-green colored oxidized TMB on the surface of the paper. The coloration was analyzed with a smartphone. The method has a 21 µM limit of detection and a linear range that extends from 0.5 to 80 mM. Graphical abstract Antimony-doped tin oxide nanoparticles (ATO NPs) combined with 3,3,5,5-tetramethybenzidine (TMB) and triethylamine were coated on the filter paper. After addition of sample solution, the blue-green colored oxidized TMB was generated and recorded by a digital camera.


Assuntos
Antimônio/química , Materiais Biomiméticos/química , Corantes/química , Glucose/análise , Nanopartículas Metálicas/química , Peroxidases/química , Smartphone/instrumentação , Compostos de Estanho/química , Benzidinas/química , Técnicas Biossensoriais/métodos , Catálise , Colorimetria/métodos , Etilaminas/química , Glucose Oxidase/química , Limite de Detecção , Oxirredução
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA