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1.
Biosens Bioelectron ; 200: 113918, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34990957

RESUMO

Novel methods that enable facile, ultrasensitive and multiplexed detection of low molecular weight organic compounds such as metabolites, drugs, additives, and organic pollutants are valuable in biomedical research, clinical diagnosis, food safety and environmental monitoring. Here, we demonstrate a simple, rapid, and ultrasensitive method for detection and quantification of small molecules by implementing a competitive immunoassay with an ultrabright fluorescent nanolabel, plasmonic fluor. Plasmonic-fluor is comprised of a polymer-coated gold nanorod and bovine serum albumin conjugated with molecular fluorophores and biotin. The synthesis steps and fluorescence emission of plasmonic-fluor was characterized by UV-vis spectroscopy, transmission electron microscopy, and fluorescence microscopy. Plasmon-enhanced competitive assay can be completed within 20 min and exhibited more than 30-fold lower limit-of-detection for cortisol compared to conventional competitive ELISA. The plasmon-enhanced competitive immunoassay when implemented as partition-free digital assay enabled further improvement in sensitivity. Further, spatially multiplexed plasmon-enhanced competitive assay enabled the simultaneous detection of two analytes (cortisol and fluorescein). This simple, rapid, and ultrasensitive method can be broadly employed for multiplexed detection of various small molecules in research, in-field and clinical settings.


Assuntos
Técnicas Biossensoriais , Nanotubos , Bioensaio , Ouro , Imunoensaio
2.
Sensors (Basel) ; 22(1)2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-35009930

RESUMO

Nitric oxide (NO) is a toxic gas, which is dangerous for human health and causes many respiratory infections, poisoning, and lung damage. In this work, we have successfully grown ZnO nanorod film on annealed ZnO seed layer in different ambient temperatures, and the morphology of the nanorods sensing layer that affects the gas sensing response to nitric oxide (NO) gas were investigated. To acknowledge the effect of annealing treatment, the devices were fabricated with annealed seed layers in air and argon ambient at 300 °C and 500 °C for 1 h. To simulate a vertical device structure, a silver nanowire electrode covered in ZnO nanorod film was placed onto the hydrothermal grown ZnO nanorod film. We found that annealing treatment changes the seed layer's grain size and defect concentration and is responsible for this phenomenon. The I-V and gas sensing characteristics were dependent on the oxygen defects concentration and porosity of nanorods to react with the target gas. The resulting as-deposited ZnO seed layer shows better sensing response than that annealed in an air and argon environment due to the nanorod morphology and variation in oxygen defect concentration. At room temperature, the devices show good sensing response to NO concentration of 10 ppb and up to 100 ppb. Shortly, these results can be beneficial in the NO breath detection for patients with chronic inflammatory airway disease, such as asthma.


Assuntos
Nanotubos , Óxido de Zinco , Eletrodos , Humanos , Óxido Nítrico , Prata
3.
J Colloid Interface Sci ; 611: 408-420, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34959012

RESUMO

Metallic nanoparticles supported on porous matrices are promising heterogeneous catalysts for Fenton-like reaction towards the degradation of organic contaminants in water. Herein, novel magnetic nanocomposites (NCs) of metallic nickel (Ni0) nanoparticles and nanotubular polyaniline matrix (PANI/Ni0 NCs) were fabricated by simple reductive formation of Ni0 nanoparticles upon the pre-synthesized PANI nanotubes (NTs) surface and applied as heterogeneous Fenton-like catalyst in degrading cationic brilliant green dye (BG) in aqueous solution. Various physico-chemical characterization techniques revealed effective supporting of soft ferromagnetic well dispersed nano-dimensional Ni0 particles onto the PANI NTs matrix. Heterogeneous Fenton-like catalytic performance of PANI/Ni0 NCs for BG degradation in the presence of hydrogen peroxide (H2O2) oxidant demonstrated their superiority when compared with unsupported Ni0 nanoparticles counterpart. Experiments with a minimum 0.1 g/L of NCs and 10 mM of H2O2 displayed complete degradation of 100 mg/L BG within 120 min reaction time. Improved BG degradation was observed with increase in the dose of PANI/Ni0, H2O2 concentration and temperature, whereas it reduced with rise in initial concentration of BG. The rate of degradation was well described by the pseudo-first- order kinetic model. Six consecutive BG degradation experiments confirmed NCs reusability without loss of original (∼100%) degradation efficiency up to the fifth cycle. Finally, liquid chromatography-mass spectrometric (LC-MS) analyses of the BG samples after 120 min degradation time exposed the formation of N,N-diethylaniline as degradation product along with partial mineralization of the other end products via the attack of reactive hydroxyl radicals (HO•) produced in the catalytic system.


Assuntos
Nanopartículas Metálicas , Nanotubos , Poluentes Químicos da Água , Compostos de Anilina , Catálise , Peróxido de Hidrogênio , Níquel , Oxirredução , Compostos de Amônio Quaternário , Água
4.
J Colloid Interface Sci ; 611: 397-407, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34963074

RESUMO

Native lipids in cell-membrane support crucial functions like intercell communication via their ability to deform into curved membrane structures. Cell membrane mimicking Giant unilamellar vesicles (GUV) is imperative in understanding native lipid's role in membrane transformation however remains challenging to assemble. We construct two giant vesicle models mimicking bacterial inner-membrane (IM) and outer-membrane (OM) under physiological conditions using single-step gel-assisted lipid swelling. IM vesicles composed of native bacterial lipids undergo small-scale membrane remodeling into bud and short-nanotube structures. In contrast, OM vesicles asymmetrically assembled from Lipopolysaccharide (LPS) and bacterial lipids underwent global membrane deformation under controlled osmotic stress. Remarkably, highly-curved structures mimicking cell-membrane architectures, including daughter vesicle networks interconnected by necks and nano-tubes ranging from micro to nanoscale, are generated in OM vesicles at osmotic stress comparable to that applied in IM vesicles. Further, we provide a quantitative description of the membrane structures by experimentally determining membrane elastic parameters, i.e., neck curvature and bending rigidity. We can conclude that a larger spontaneous curvature estimated from the neck curvature and softer membranes in OM vesicles is responsible for large-scale deformation compared to IM vesicles. Our findings will help comprehend the shape dynamics of complex native bacterial lipid membranes.


Assuntos
Nanotubos , Lipossomas Unilamelares , Membrana Celular , Lipídeos
5.
J Environ Sci (China) ; 111: 175-184, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34949347

RESUMO

Herein, a series of niobium oxide supported cerium nanotubes (CeNTs) catalysts with different loading amount of Nb2O5 (0-10 wt.%) were prepared and used for selective catalytic reduction of NOx with NH3 (NH3-SCR) in the presence of CH2Cl2. Commercial V2O5-WO3-TiO2 catalyst was also prepared for comparison. The physcial properties and chemical properties of the Nb2O5 loaded cerium nanotubes catalysts were investigated by X-ray diffractometer, Transmission electron microscope, Brunauer-Emmett-Teller specific surface area, H2-temperature programmed reduction, NH3-temperature programmed desorption and X-ray photoelectron spectroscopy. The experiment results showed that the loading amount of Nb2O5 had a significant effect on the catalytic performance of the catalysts. 10 wt.% Nb-CeNTs catalyst presented the best NH3-SCR performance and degradation efficiency of CH2Cl2 among the prepared catalysts, due to its superior redox capability, abundant surface oxygen species and acid sites, the interaction between Nb and Ce, higher ratio of Nb4+/(Nb5++ Nb4+) and Ce3+/(Ce3+ + Ce4+), as well as the special tubular structure of cerium nanotube. This study may provide a practical approach for the design and synthesis of SCR catalysts for the simultaneously removal NOx and chlorinated volatile organic compounds (CVOCs) emitted from the stationary industrial sources.


Assuntos
Cério , Nanotubos , Amônia , Catálise , Cloreto de Metileno , Nióbio , Oxirredução , Titânio
6.
J Environ Sci (China) ; 115: 173-189, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34969447

RESUMO

All-solid-state Z-scheme photocatalysts, containing Cu2O, TiO2 (rutile), and Au as the electron mediator, were prepared and applied to the reduction of Cr(VI) in aqueous solutions. The Cu2O-Au-TiO2 composites were prepared by loading Au core-Cu2O shell hemisphere particles on TiO2 (rutile) nanorods using a two-step photocatalytic deposition process. Under ultraviolet-visible (UV-vis) light illumination, the Cu2O-Au-TiO2 composites exhibited higher photocatalytic Cr(VI) reduction activities than those exhibited by single TiO2 (rutile) and Cu2O. In this reaction, a precipitate containing Cr, which was considered to be Cr(OH)3, was deposited site-selectively on the Au core-Cu2O shell particles of the composites, indicating that the reduction site of the composite was Cu2O, and the reaction proceeded according to the Z-scheme. The Cu2O-Au-TiO2 composites also exhibited photocatalytic activity under visible light illumination. The oxidation state of Cu in the Cu2O-Au-TiO2 composite gradually changed from Cu(I) to Cu(II) during the photocatalytic Cr(VI) reduction. However the composite maintained its high photocatalytic performance even after oxidation. The role of Au in the Cu2O-Au-TiO2 composite was examined by comparing the properties of the Cu2O-Au-TiO2 composite with those of the Cu2O-TiO2 composite prepared via direct Cu2O deposition on TiO2.


Assuntos
Nanotubos , Água , Catálise , Cromo , Titânio
7.
J Colloid Interface Sci ; 610: 89-97, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34922085

RESUMO

Synergistic therapy has been emerging as new trend for effective tumor treatment due to synchronous function and cooperative reinforcement of multi therapeutic modalities. Herein, gold nanorods (GNRs) encapsulated into polypyrrole (PPy) shell with tunable void space (GNRs@Void@PPy) showing yolk@shell nanostructures were innovatively designed. The exploitation of dual near-infrared (NIR) absorptive species offered synergistic enhancement of photothermal performance. In addition, the manipulation of the void space between them provided additional benefits of high drug encapsulation efficiency (92.6%) and, interestingly, tumor microenvironment and NIR irradiation triggered targeted drug releasing. Moreover, the GNRs@Void@PPy exhibited excellent biocompatibility, and optimal curative effect by chemo-photothermal synergistic therapy was achieved through both in vitro and in vivo antitumor activity investigation.


Assuntos
Nanotubos , Neoplasias , Preparações Farmacêuticas , Linhagem Celular Tumoral , Doxorrubicina , Ouro , Humanos , Neoplasias/tratamento farmacológico , Fototerapia , Polímeros , Pirróis , Microambiente Tumoral
8.
Talanta ; 239: 123146, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34942484

RESUMO

A high-performance sensing layer based on dual-template molecularly imprinted polymer (DMIP) was fabricated and successfully applied for one-by-one detection of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) as lung cancer biomarkers. The plastic antibodies of AFP and CEA were created into the electropolymerized polypyrrole (PPy) on a fluorine-doped tin oxide (FTO) electrode. Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests were performed to pursue the formation and characterization of the sensing layer. Methyl orange (MO) increased the conductivity of PPy and induced the formation of MO doped PPy (PPy-MO) rectangular-shaped nanotubes. Using impedimetric detection, the rebinding of the template antigens was evaluated, the charge transfer resistance increased as the concentration of AFP and CEA increased. The linear dynamic ranges of 5-104 and 10-104 pg mL-1 and detection limits of 1.6 and 3.3 pg mL-1 were obtained for CEA and AFP, respectively. Given satisfactory results in the determination of AFP and CEA in the human serum samples, high sensitivity, and good stability of DMIP sensor made it a promising method for sensing of AFP and CEA in serum samples.


Assuntos
Técnicas Biossensoriais , Impressão Molecular , Nanotubos , Neoplasias , Biomarcadores Tumorais , Antígeno Carcinoembrionário , Técnicas Eletroquímicas , Eletrodos , Humanos , Limite de Detecção , Pulmão , Polímeros , Pirróis , alfa-Fetoproteínas
9.
Talanta ; 237: 122930, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736667

RESUMO

Given increasing concern regarding antibiotic environmental contamination, there is immediate need to monitor antibiotic levels to effectively control pollution. In this study, we used a photoelectrochemical aptasensor based on TiO2@MoS2 spiral nanoarrays to detect chloramphenicol (CAP) in antibiotics. Nanoarrays were directly grown on fluorine-doped tin oxide (FTO) conductive glass with excellent biochemical stability, while aptamer-SH were immobilized by chemical binding on a synthetic TiO2@MoS2 nanoarray. Results show that the photocurrents were reduced in the presence of photoelectrochemistry associated with specific selection of aptamer for CAP. When the measurement of the fabricated nanomaterial chip was carried out using a three-electrode system, we found a highly specific and stable detection of chloramphenicol that ranged between 0.1 pM and 1 µM, with the detection limit of 0.1 pM. In addition, we obtained satisfactory results when real sample were used to validate the potential of photoelectrochemical (PEC) aptasensor for detecting chloramphenicol content in milk. Our results demonstrate that photoelectrochemical aptasensor is conducive to the development of less toxic multifunctional nanomaterials, making the biosensor more robust and environmentally friendly. Therefore, photoelectrochemical aptasensor can be widely applied in the field of environmental monitoring.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanotubos , Técnicas Eletroquímicas , Limite de Detecção , Titânio
10.
Anal Chim Acta ; 1189: 339204, 2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34815043

RESUMO

Electrochemical sensing methods monitor biomolecules because of their specificity, rapid response, lower cost, and automation. Hemoglobin is an abundant protein in the human body and is correlated with various physiological processes. Levels of hemoglobin in blood are associated with anemia in pregnant women. In this research, a non-enzymatic sensor based on NiTe nanorods is developed for the detection and quantification of hemoglobin (Hb) from anemic pregnant patients. NiTe nanorods are synthesized by the single-step method. After characterizing the material, sensing parameters such as the effect of scan rate, pH, concentration, and interferences are optimized using standard hemoglobin samples. Linearity, the limit of detection (LOD), and the limit of quantification (LOQ) for NiTe nanorods are 0.99698, 0.012 nM, and 0.04 nM, respectively. Stability is measured by cyclic chronoamperometry (12 h) and voltammetry (100 cycles). Recovery of hemoglobin from blood samples is in the range of 63-90%. NiTe nanorods quantitatively determine hemoglobin from the blood samples of anemic pregnant women.


Assuntos
Anemia , Nanotubos , Anemia/diagnóstico , Técnicas Eletroquímicas , Feminino , Hemoglobinas/análise , Humanos , Gravidez , Gestantes
11.
Chemosphere ; 287(Pt 3): 132168, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826931

RESUMO

For the photocatalytic test, gold nanoparticles (AuNPs) were prepared using trisodium citrate dehydrate (TCD), following which they were combined on the surface of zinc oxide (ZnO) to prepare ZnO decorated with uniform AuNPs (ZnO/AuNP) photocatalysts. The photocatalytic performance with the ZnO/AuNP was estimated through the rhodamine B (RB) dye degradation under solar irradiation. ZnO/AuNP-30 showed the greatest photocatalytic performance, achieving dye degradation efficiency up to 78.65%. Photoelectrochemical (PEC) measurements were performed using the ZnO/AuNP photoanodes. With AuNP doping amounts of 10, 20, and 30 mL on the ZnO surface, photocurrent densities of 47.46, 63.74, and 68.64 mA cm-2, respectively, were achieved at an applied voltage of 1.5 V. These values indicated that the doping of AuNPs on the ZnO surface is advantageous for enhancing its PEC water-splitting activity. The highest solar-to-hydrogen (STH) efficiency is 22% with the ZnO/AuNP-30 photoanode at an applied voltage of 0.88 V. The interfacial charge-transfer resistances at the interface were 40 and 2.2 kΩ cm2 for the ZnO and ZnO/AuNP-30 photoanodes, respectively.


Assuntos
Nanopartículas Metálicas , Nanotubos , Óxido de Zinco , Ouro , Água
12.
Chemosphere ; 287(Pt 3): 132278, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826939

RESUMO

The study explored the characteristics and effectiveness of modified TiO2 nanotubes with zeolite as a composite photocatalyst (MTNZC) for the degradation of triclocarban (TCC) from the aqueous solution. MTNZC samples have been produced via electrochemical anodisation (ECA) followed by electrophoretic deposition (EPD). Three independent factors selected include MTNZC size (0.5-1 cm2), pH (3-10), and irradiation time (10-60 min). The observation revealed that the surface of Ti substrate by the 40 V of anodisation and 3 h of calcination was covered with the array ordered, smooth and optimum elongated nanotubes with average tube length was approximately 5.1 µm. EDS analysis proved the presence of Si, Mg, Al, and Na on MTNZC due to the chemical composition present in the zeolite. The average crystallite size of TiO2 nanotubes increased from 2.07 to 3.95 nm by increasing anodisation voltage (10, 40, and 60 V) followed by 450 °C of calcination for 1, 3, and 6 h, respectively. The optimisation by RSM shows the F-value (36.12), the p-value of all responses were less than 0.0001, and the 95% confidence level of the model by all the responses indicated the model was significant. The R2 in the range of 0.9433-0.9906 showed the suitability of the model to represent the actual relationship among the parameters. The photocatalytic degradation rate of TCC from the first and the fifth cycles were 94.2 and 77.4%, indicating the applicability of MTNZC to be used for several cycles.


Assuntos
Nanotubos , Zeolitas , Carbanilidas , Catálise , Titânio
13.
J Colloid Interface Sci ; 607(Pt 1): 607-620, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34520904

RESUMO

A photocatalytic process was used to effectively remove glyphosate, an emerging pollutant and contaminant, through advanced oxidation. For this purpose, a feasible combination strategy of two-step anodisation and electrodeposition methods were proposed to fabricate graphene quantum dots (GQDs) supported titanium dioxide nanotube arrays (TNAs). The resultant GQDs/TNAs heterojunction composite exhibited significant degradation reactivity and circulation stability for glyphosate due to its excellent photo-generated electron and hole separation ability. After the introduction of GQDs into TNAs, the photodegradation efficiency of glyphosate increased from 69.5% to 94.7% within 60 min under UV-Vis light irradiation (λ = 320-780 nm). By analysing the intermediate products and through the evolvement of heteroatoms during glyphosate photodegradation, alanine and serine were discovered for the first time, and a detailed degradation mechanism of glyphosate was proposed. This study indicates that GQDs/TNAs heterojunction composite can almost completely degrade the glyphosate into inorganics under the appropriate conditions.


Assuntos
Grafite , Nanotubos , Pontos Quânticos , Catálise , Glicina/análogos & derivados , Luz , Titânio
14.
J Colloid Interface Sci ; 607(Pt 1): 857-868, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34534769

RESUMO

In this study, a new hollow nanotube material, 30% Co-CHNTs was prepared by the impregnation-chemical reduction-calcination method. This material can be used as a peroxymonosulfate (PMS) activator to catalyse the degradation of sulfamethoxazole (SMX). The best reaction conditions that correspond to the degradation rate of SMX, up to 97.5%, are as follows: the concentration of SMX is 10 mg L-1, the amount of catalyst is 0.20 g L-1, the dosage is 1.625 mM, and the solution pH is 6.00. X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectrometry (ICP-OES) show that the calcined composites mainly stimulate an increase in the content of bivalent cobalt in PMS and reduce the leaching of cobalt ions after the reaction. Additionally, the 30% Co-CHNTs + PMS reaction system exhibits a reasonable SMX degradation rate in a natural organic matter solution and excellent stability after three repeated experiments. Furthermore, the possible degradation mechanism in the 30% Co-CHNTs + PMS reaction system was analysed through electron paramagnetic resonance (EPR) and free-radical capture experiments, and it was observed that the non-radical degradation of 1O2 plays a leading role in SMX degradation. Finally, according to the nine degradation intermediates detected by liquid chromatography-mass spectrometry (LC-MS), four possible SMX degradation routes were proposed. This study proved that a 30% Co-CHNTs heterogeneous catalyst is easily prepared, inexpensive, and environmentally friendly and has potential application in antibiotic wastewater treatment.


Assuntos
Nanotubos , Poluentes Químicos da Água , Argila , Cobalto , Óxidos , Peróxidos , Sulfametoxazol , Poluentes Químicos da Água/análise
15.
Chemosphere ; 287(Pt 4): 132379, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34597637

RESUMO

Tuning a graphitic carbon nitride (CN) structure is an effective strategy to advance its physicochemical and electronic properties. Herein, hierarchical CN nanorods with carbon vacancy were synthesized via ultrasound-assisted thermal polycondensation method wherein melamine-HONH2·HCl complex acts as a template. The hierarchical CN nanorods can facilitate multiple light scattering, provide large specific surface area with extensive reactive sites and endow abundant mass-transport channels for charge migration. The existence of carbon vacancies can serve as shallow charge trapping sites and prompt charge separation. Consequently, hierarchical CN nanorod possessed excellent sonophotodegradation efficiency of ∼100% towards Tetracycline (TC) antibiotic within 60 min under ultrasonic irradiation and visible light illumination. Moreover, the sonophotocatalytic degradation was higher than the sum of sonocatalytic and photocatalytic TC degradation using hierarchical CN nanorods due to its synergistic performance. A plausible sonophotocatalytic mechanism and TC degradation pathway using hierarchical CN nanorod were proposed. Lastly, hierarchical CN nanorod is durable and stable which can withstand the sonophotocatalytic condition even after the fifth run. This work offers an insight into hierarchical CN nanorod to advance sonophotocatalytic degradation performance for highly efficient removal of various recalcitrant pollutants.


Assuntos
Carbono , Nanotubos , Antibacterianos , Catálise , Grafite , Compostos de Nitrogênio , Tetraciclina
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120458, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34619508

RESUMO

Near-infrared (NIR) photothermal therapy is an effective partner to the chemotherapy of tumors with the merits of high therapeutic ability and slight side effect on normal tissues. Herein, we synthesized gold nanorods and assembled them with L-cysteine reduced graphene oxide (AuNR@Lcyst-rGO) for efficient photothermal therapy. The high therapeutic efficacy of AuNR@Lcyst-rGO can be due to the high photothermal effect of gold nanorods and reduced graphene oxide, and the synergistic effect of them. The nontoxicity of L-cysteine also guarantees the comfortable biocompatibility of reduced graphene oxide, which is essential for the photothermal absorber used in human tissue. The results demonstrate that assembly of gold nanorods with reduced graphene oxide (AuNR@Lcyst-rGO) is a promising photothermal agent with high efficient NIR-triggered photothermal therapy efficiency, excellent stability, superior biocompatibility.


Assuntos
Grafite , Nanotubos , Neoplasias , Linhagem Celular Tumoral , Cisteína , Ouro , Humanos , Neoplasias/terapia , Fototerapia , Terapia Fototérmica
17.
Food Chem ; 370: 131276, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34662790

RESUMO

This study presented an effective and sensitive SERS substrate for rapid detection of thiabendazole (TBZ) in fruit samples. A core-shell gold/silver nanorod (Au@Ag NRs) has been synthesized as a bimetallic SERS-active substrate. The obtained substrate showed an excellent SERS effect because of the tunable plasmon resonance of Au NRs, the significantly enhanced effect of silver, and the bimetallic synergistic effect of Au@Ag NRs. Under optimal conditions, the substrate was used to detect TBZ in fresh apple juice and peach juice with limits of detection of 0.032 and 0.034 ppm respectively. In addition, the recovery rate was within a satisfactory range of 95-101%, indicating that the Au@Ag NRs substrate could be a SERS detection platform for fruit pesticides residues with great development potential.


Assuntos
Nanopartículas Metálicas , Nanotubos , Sucos de Frutas e Vegetais , Ouro , Análise Espectral Raman , Tiabendazol/análise
18.
Nanoscale ; 14(2): 482-491, 2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-34908094

RESUMO

Indirect monitoring of Listeria monocytogenes (LM) via a gas sensor that can detect the bacterial metabolite 3-hydroxy-2-butanone (3H-2B) is a newly emerged strategy. However, such sensors are required simultaneously endow with outstanding selectivity, high sensitivity, and ppb-level detection limit, which remains technologically challenging. Herein, we have developed highly selective and sensitive 3H-2B sensors that consist of zinc oxide nanorods decorated with cobaltosic oxide nanoparticles (ZnO NRs/Co3O4 NPs), which have been synthesized by combined optimized hydrothermal and annealing process. Specifically, the ZnO NRs/Co3O4 NPs exhibit ultrahigh sensitivity to 5 ppm 3H-2B (Ra/Rg = 550 at 260 °C). The sensor prototypes enable detection as low as 10 ppb 3H-2B, show excellent long-term stability, and present remarkable selectivity through interfering selectivity survey and principal component analysis (PCA). Such outstanding sensing performance is attributed to the modulated electron depletion layer by n-p heterojunctions and abundant gas diffusion pathways via the radial architecture, which was verified via electrochemical impedance spectroscopy test, Mott-Schottky measurement, and ultraviolet-visible absorption analysis. Our highly selective and sensitive ZnO NRs/Co3O4 NPs have the potential in the real-time detection of 3H-2B biomarker.


Assuntos
Nanopartículas , Nanotubos , Óxido de Zinco , Acetoína , Biomarcadores , Cobalto , Óxidos
19.
Methods Mol Biol ; 2371: 449-466, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34596863

RESUMO

Cyclic peptides are a fascinating class of molecules that can be programmed to fold or self-assemble into diverse mono- and multidimensional structures with potential applications in biomedicine, nanoelectronics, or catalysis. Herein we describe on-resin procedures to carry out head-to-tail peptide cyclization based on orthogonal protected linear structures. We also present essential characterization tools for obtaining dynamic and structural information, including the visualization cyclic peptide assembly into nanotubes (AFM, TEM) as well as the use of fluorescence microscopy.


Assuntos
Peptídeos Cíclicos/química , Catálise , Ciclização , Nanotubos
20.
Chemosphere ; 286(Pt 1): 131608, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34298296

RESUMO

In this study, cuprous oxide modified titanate nanotube arrays photocatalyst (Cu2O/TNAs), a p-n type hetero-structure, was successfully synthesized by square wave voltammetry electrodeposition method (SWVE) with copper (II) acetate monohydrate as precursor. Cu2O/TNAs photocatalysts were characterized by SEM, XRD, XPS, and UV-vis DRS to investigate the physical and chemical properties such as surface structure, light absorption, and element composition. Results of characterization indicated that the Cu2O nanoparticles (Cu2O NPs) were firmly deposited on the surface of TNAs without significant morphological change. The enhanced photocatalytic (PC) performance of as-synthesized materials was exemplified by the test of photocurrent, which revealing that the average photocurrent density of Cu2O/TNAs (0.95 µA cm-2) was 1.38 times higher than TNAs (0.69 µA cm-2) under 24.2 mW cm-2 LED irradiation. Three VOCs (volatile organic compounds), namely, Toluene, Formaldehyde and Trichloroethylene can be completely removed in the Cu2O/TNAs PC process with rate constants (kobs) of 2.08 × 10-2, 3.11 × 10-2, and 6.58 × 10-2 min-1, respectively, with the effort of the synergism of the photo-generated holes and hydroxyl radicals. Detail mechanism of hetero-junction Cu2O/TNAs composite PC system was proposed to clarify the redox reaction.


Assuntos
Nanotubos , Tricloroetileno , Catálise , Cobre , Formaldeído , Tolueno
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