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1.
Poult Sci ; 101(5): 101725, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35299067

RESUMO

Ferroptosis is a newly discovered form of cell death due to iron-dependent lipid peroxidation. In animal breeding, many environmental factors could lead to oxidative stress, which in turn reduce animal immunity and production performance. Polysaccharide of Atractylodes macrocephala Koidz (PAMK) has antioxidation, immunomodulatory, and inflammatory modulating effects. For investigating the effect of PAMK on splenic ferroptosis in gosling caused by lipopolysaccharide (LPS), 40 one-day-old Magang goslings were randomly divided into 4 groups (CON group, LPS group, PAMK group, and LPS+PAMK group). The protein expression of the ferroptosis marker Glutathione Peroxidase 4 (GPX4), the relative mRNA expression of ferroptosis-related genes and cytokines, and the oxidative stress and iron content of spleen tissues were examined. The correlation between ferroptosis and inflammatory factors was further analyzed by principal component analysis. The results showed that, compared with CON group, LPS caused alterations in the expression of the ferroptosis pathway genes and cytokines, which could upregulate levels of ferroptosis and inflammation. However, after treated with PAMK, the inflammation and ferroptosis was alleviated. Meanwhile, PAMK restored the expression and distribution of GPX4. In addition, PAMK alleviated the oxidative stress caused by LPS and reduced the iron content in spleen. Principal component analysis showed that cytokines were more closely related to antioxidant indexes. The CON, PAMK and LPS+PAMK groups had similar effects on the four components, with the LPS and PAMK groups showing the furthest difference in results. The result indicated that PAMK could reduce the level of oxidative stress and inflammatory cytokines in spleen of gosling caused by LPS, and jointly alleviate ferroptosis by regulating genes related to the ferroptosis pathway.


Assuntos
Atractylodes , Ferroptose , Animais , Antioxidantes/metabolismo , Galinhas , Citocinas/genética , Citocinas/metabolismo , Carboidratos da Dieta/metabolismo , Gansos , Inflamação/induzido quimicamente , Inflamação/metabolismo , Inflamação/veterinária , Ferro/metabolismo , Lipopolissacarídeos/toxicidade , Polissacarídeos/farmacologia , Baço
2.
Anal Chim Acta ; 1190: 339264, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34857144

RESUMO

A surface acoustic wave (SAW) gas sensor with an Au/TiO2/poly(3,4-ethylenedioxythiophene) (PEDOT, which is a conductive polymer with photoelectric conversion function) sensing film was constructed for the quantitative detection of water vapor and CO2. The Au/TiO2/PEDOT sensing film was assembled on the delayed region of the 204 MHz SAW delay line, which was used as the base device for the gas sensor. The center frequency of the sensor decreases with an increase in relative humidity (RH), and the center frequency increases with increasing CO2 concentration, so that not only can the two gases be identified, but quantitative analysis can also be performed. The SAW sensor has a response range of 5%-90% for RH and a response range of 500-2000 ppm for CO2 gas. The shifts in center frequency varied linearly with the concentrations, giving rise to the sensitivities of -0.0068 and -0.1880 kHz %-1 for RH and ∼0.003 kHz ppm-1 CO2. The response/recovery time is 9 s/9.2 s for 700 ppm CO2 and 15 s/14 s for 70% RH. The experimental results show that the SAW sensor offers excellent selectivity, wide response range, rapid response, and good stability and repeatability. The mechanism of humidity and CO2 sensing is attributed to the hydrophilic porous structure of the Au/TiO2/PEDOT sensing film, and also to the reversible variation of its viscoelasticity under illumination conditions. The sensor, combined with the communication function of its own SAW device, has several prospective applications in the monitoring of atmospheric conditions.


Assuntos
Dióxido de Carbono , Som , Compostos Bicíclicos Heterocíclicos com Pontes , Umidade , Polímeros , Titânio
3.
Biosens Bioelectron ; 187: 113326, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34004544

RESUMO

High-efficiency electroencephalogram (EEG) dry electrodes are a key component of brain-computer interface (BCI) technology because of their direct contact with the scalp. In this study, a semi-flexible polydopamine (PDA)/Pt-TiO2 electrode is prepared for the dry-contact acquisition of EEG signals. The PDA biofilm adheres strongly to the scalp and maintains a dynamic balance of water and ions. The Pt nanoparticles and TiO2 nanotube array together result in fast electron transfer. Therefore, the interface impedance between the dry PDA/Pt-TiO2 electrode and scalp is as low as 19.63-24.53 kΩ. The spontaneous EEG signal collected simultaneously using the dry PDA/Pt-TiO2 and wet Ag/AgCl electrodes had a correlation coefficient of up to 99.9%. In a steady-state visual evoked potential (SSVEP)-based BCI system, the dry electrode was used to collect EEG feedback signals for stimulations at 27 different frequencies in the range of 7-19.25 Hz. For these feedback signals, O1, Oz, and O2 channels in the occipital area exhibited high signal-to-noise ratios of 11.3, 11.8, and 11 dB, respectively. A volunteer wore an EEG headband with three PDA/Pt-TiO2 dry electrodes and successfully controlled the robotic arm of the SSVEP-BCI system in the untrained mode. The dry PDA/Pt-TiO2 electrode-based EEG cap is comfortable to wear, the identification signals of the SSVEP paradigm are accurate, and it is suitable for controlling external devices including a keyboard in the SSVEP-BCI system.


Assuntos
Técnicas Biossensoriais , Interfaces Cérebro-Computador , Eletrodos , Eletroencefalografia , Potenciais Evocados Visuais , Humanos
4.
Anal Chim Acta ; 1145: 103-113, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33453871

RESUMO

The in vivo detection of small active molecules in plant tissues is essential for the development of precision agriculture. Tryptophan (Trp) is an important precursor material for auxin biosynthesis in plants, and the detection of Trp levels in plants is critical for regulating the plant growth process. In this study, an electrochemical plant sensor was fabricated by electrochemically depositing a polydopamine (PDA)/reduced graphene oxide (RGO)-MnO2 nanocomposite onto a glassy carbon electrode (GCE). PDA/RGO-MnO2/GCE exhibited high electrocatalytic activity for the oxidation of Trp owing to the combined selectivity of PDA and catalytic activity of RGO-MnO2. To address the pH variability of plants, a reliable Trp detection program was proposed for selecting an appropriate quantitative detection model for the pH of the plant or plant tissue of interest. Therefore, a series of linear regression curves was constructed in the pH range of 4.0-7.0 using the PDA/RGO-MnO2/GCE-based sensor. In this pH range, the linear detection range of Trp was 1-300 µM, the sensitivity was 0.39-1.66 µA µM-1, and the detection limit was 0.22-0.39 µM. Moreover, the practical applicability of the PDA/RGO-MnO2/GCE-based sensor was successfully demonstrated by determining Trp in tomato fruit and juice. This sensor stably and reliably detected Trp levels in tomatoes in vitro and in vivo, demonstrating the feasibility of this research strategy for the development of electrochemical sensors for measurements in various plant tissues.


Assuntos
Grafite , Técnicas Eletroquímicas , Indóis , Compostos de Manganês , Óxidos , Polímeros , Triptofano
5.
Mikrochim Acta ; 187(12): 671, 2020 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-33225378

RESUMO

A ternary hybrid material composed of Ni nanoparticles (NPs), TiO2 NPs, and poly(L-lysine) (Ply) was used as a sensing material. It was electrodeposited in situ onto a commercial 433-MHz surface acoustic wave (SAW) resonator to construct a Ni-TiO2-Ply/SAW sensor. The Ni-TiO2-Ply sensing layer fully covered the resonant cavity of the SAW resonator. As the sensing layer completely covers the interdigital transducer and piezoelectric substrate, the sensing area is significantly increased, and the resonator is protected from damage or contamination. To detect the level of dopamine (DA) in serum, the fabrication of the Ni-TiO2-Ply sensing layer, distributions of various components in the sensing layer, and responses of the SAW biosensor to DA were investigated in detail. In addition, an electric field-assisted liquid-phase oxidation technique was developed for loading analytes onto the SAW sensors. After optimizing the pH value and L-lysine content of the sensing layer electrolyte and the pH value of the DA solution, the SAW biosensor responded to DA with a linear concentration range of 1 to 1000 nM, sensitivity of 5.77 MHz nM-1 cm-2, and limit of detection of 0.067 nM. Moreover, the sensor exhibited good selectivity, reproducibility, and stability at ambient temperature.Graphical abstract.


Assuntos
Técnicas Biossensoriais/métodos , Dopamina/análise , Níquel/química , Polilisina/química , Titânio/química , Dopamina/sangue , Limite de Detecção , Reprodutibilidade dos Testes , Som
6.
Anal Chim Acta ; 1135: 73-82, 2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33070861

RESUMO

In this study, boron-doped diamond (BDD) electrodes with varied B contents are prepared to determine the feasibility of the direct usage of BDD as an electrochemical biosensor without any modification. The electrochemical performance of the electrodes was investigated through the characterization of electrochemical impedance spectroscopy for potassium ferricyanide/potassium ferrocyanide (K3Fe(CN)6/K4Fe(CN)6) redox couples, as well as through qualitative and quantitative analysis of the two biomolecules dopamine (DA) and melatonin (MLT). The results show that the B content of BDD is the primary parameter for controlling the electrocatalytic current, that is, the response sensitivity. However, the abundant crystal planes and low background current are the key factors in improving the selectivity of the biomarkers to identify multiple analytes. Considering the catalytic current and its ability to distinguish the biomolecules, BDD with a B source carrier gas flow rate of 18 sccm is used as the sensing electrode for the simultaneous detection of DA and MLT. The response peak potential difference reaches 500 mV, and the linear concentration range for the two analytes is 0.4-600 µM, with detection limits of 0.1 µM for DA and 0.003 µM for MLT. These results match those observed for electrochemical sensors modified by various sensitive materials. BDD electrodes show good chemical resistance, good stability, and no pollution and are suitable for long-term usage as biomarker sensors.


Assuntos
Técnicas Biossensoriais , Melatonina , Boro , Diamante , Dopamina , Eletrodos
7.
Biosens Bioelectron ; 170: 112675, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33038583

RESUMO

A miniaturized biosensor was developed for in situ noninvasive detection of glucose in sweat. The biosensor was composed of a pair of interdigital Pt-poly(L-lactic acid) (Pt-PLA) microelectrode arrays operating as the working and auxiliary electrode. The size of the sensor was 3.56 × 0.72 mm, while the width of the interdigital microelectrodes was 2.4 µm. The microelectrodes with densely packed coral-like Pt-PLA nanoparticles were fabricated using a multi-potential step deposition process. We investigated the influence of the Pt-PLA electrodeposition time on the morphology and electrochemical performance of the microelectrode. The optimized biosensor exhibited high electrocatalytic activity because of the synergistic effects between the Pt nanoparticles and PLA polymer matrix, including the electrooxidation of Pt on glucose, the adsorption of glucose by the PLA polymer, and the acceleration of the glucose dehydrogenation step. For glucose detection in sweat and tears, the linear concentration ranges were observed to be 0.001-33.76 µM and 33.76-1000 µM, with a low detection limit of 0.19 nM. The miniaturized biosensor exhibited high sensitivity and signal stability, and could be suitable for use in the long-term monitoring of sweat glucose levels in patients, athletes, and other subjects in various difficult environments.


Assuntos
Técnicas Biossensoriais , Glucose Oxidase , Enzimas Imobilizadas , Glucose , Humanos , Ácido Láctico , Microeletrodos , Platina , Poliésteres , Suor
8.
J Mater Chem B ; 8(2): 298-307, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31808501

RESUMO

In this study, a sandwich-type electrochemical (EC) immunosensor was proposed to detect a carcinoembryonic antigen (CEA) based on Au-graphene and Au@SiO2-methylene blue (MB). The Au nanoparticles (NPs)-vertical graphene (VG) electrode efficiently amplifies the response signal by immobilizing a large amount of the coating antibody (Ab) and is characterized by excellent electrocatalytic activity. The MB nanodot-loaded Au@SiO2 carriers with core-shell nanostructure and detection Ab were used to construct the Ab-Au@SiO2-MB label, which improved the sensitivity due to the high EC signal of MB nanodots and the high labeling effect between the detection Ab and MB probe. A novel double-Ab sandwich strategy was developed to further improve the sensitivity and stability based on the same specificity of the coating and detection Abs for the recognition of CEA. Under optimal conditions, the developed EC sensor exhibited a wide linear range from 1 fg mL-1 to 100 ng mL-1, with an ultralow detection limit of 0.8 fg mL-1 (S/N = 3). The feasibility in the clinical application of the EC sensor was verified by the in vitro detection of CEA in human serum.


Assuntos
Técnicas Biossensoriais/métodos , Antígeno Carcinoembrionário/sangue , Técnicas Eletroquímicas/métodos , Imunoensaio/métodos , Anticorpos Imobilizados/química , Eletrodos , Ouro/química , Humanos , Nanopartículas Metálicas/química , Azul de Metileno , Dióxido de Silício
9.
Biosens Bioelectron ; 132: 68-75, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30856429

RESUMO

We proposed label-free and sandwich-type electrochemical immunosensors for the quantification of alpha-fetoprotein (AFP), which plays a critical role in the early diagnosis of primary liver cancer. Both detection strategies involved monitoring of the electrochemical response current of the AuPt-vertical graphene (VG)/glassy carbon electrode (GCE) for the oxidation of the redox probe, methyl orange. AuPt nanoparticles, which have good biocompatibility and excellent conductivity, were used to immobilize the primary antibody, Ab1, while VG sheets helped accelerate electron transfer at the liquid-solid and solid-solid interfaces. The sensing electrode played a key role in signal amplification, and the sensitivity of the sandwich-type sensor was higher than that of the label-free sensor. The former exhibited a wide linear range from 1 fg mL-1 to 100 ng mL-1 and a low detection limit of 0.7 fg mL-1 under the optimal experimental conditions. The excellent performance of the AuPt-VG/GCE-based immunosensors in AFP detection in human serum, coupled with their good stability, makes them promising tools for the clinical monitoring of AFP and other tumor markers.


Assuntos
Anticorpos Imobilizados/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Grafite/química , Nanopartículas Metálicas/química , alfa-Fetoproteínas/análise , Biomarcadores Tumorais/análise , Biomarcadores Tumorais/sangue , Carbono/química , Eletrodos , Ouro/química , Humanos , Imunoensaio/métodos , Limite de Detecção , Modelos Moleculares , Platina/química
10.
Sci Rep ; 7(1): 7044, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28765640

RESUMO

The development of electrochemical biosensors for the simultaneous detection of ascorbic acid (AA), dopamine (DA), uric acid (UA), tryptophan (Trp), and nitrite ([Formula: see text]) in human serum is reported in this work. Free-standing graphene nanosheets were fabricated on Ta wire using the chemical vapor deposition (CVD) method. CVD graphene, which here served as a sensing platform, provided a highly sensitive and selective option, with detection limits of AA, DA, UA, Trp, and [Formula: see text] of 1.58, 0.06, 0.09, 0.10, and 6.45 µM (S/N = 3), respectively. The high selectivity of the electrode is here explained by a relationship between the bandgap energy of analyte and the Fermi level of graphene. The high sensitivity in the oxidation current was determined by analyzing the influence of the high surface area and chemical structure of free-standing graphene nanosheets on analyte adsorption capacity. This finding strongly indicates that the CVD graphene electrode can be used as a biosensor to detect five analytes in human serum.


Assuntos
Fatores Biológicos/análise , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Grafite/metabolismo , Nanotecnologia/métodos , Soro/química , Humanos , Sensibilidade e Especificidade
11.
Mater Sci Eng C Mater Biol Appl ; 79: 740-747, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28629075

RESUMO

In this paper, we describe a method for fabricating dry electrodes for use in recording electroencephalograms (EEGs), which are based on the use of chitosan (Ch), gold (Au) particles, and titanium dioxide (TiO2) nanotube arrays deposited on titanium (Ti) thin sheets. The samples were characterized by scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy, and EEG signal collection. The TiO2 nanotube arrays were grown on the Ti thin sheet by an electrochemical anodic oxidation method. The Au particles were deposited on the bottom and surface layers of the TiO2 nanotube array using an electrochemistry-based multi-potential step technology. The fabricated dry Ch/Au-TiO2 electrodes have an efficient conversion interface for ion current/electron current, a high biocompatible contact surface, and a fast electron transfer channel. To confirm that the Ch/Au-TiO2 layer can be used in dry EEG electrodes, the impedance spectra of the electrodes in solution and skin were analyzed. The mean impedance values for skin were found to be approximately 169±33.0kΩ at 2.15Hz and 67.4±8.9kΩ at 100Hz. In addition, EEG signals from the forehead and sites with hair were collected using both the dry Ch/Au-TiO2 electrode and a wet Ag/AgCl electrode for comparison purposes. It was found that high quality EEG signal recordings could be obtained using the dry electrodes. The fact that electrolytes are not required means that the electrodes are suitable for use in long-term bio-potential testing.


Assuntos
Nanotubos , Quitosana , Eletrodos , Eletroencefalografia , Titânio
12.
Mater Sci Eng C Mater Biol Appl ; 72: 425-432, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28024606

RESUMO

Vertically stacked graphene nanosheet/titanium carbide nanorod array/titanium (graphene/TiC nanorod array) wires were fabricated using a direct current arc plasma jet chemical vapor deposition (DC arc plasma jet CVD) method. The graphene/TiC nanorod arrays were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction spectroscopy. The TiO2 nanotube array was reduced to the TiC nanorod array, and using those TiC nanorods as nucleation sites, the vertical graphene layer was formed on the TiC nanorod surface. The multi-target response mechanisms of the graphene/TiC nanorod array were investigated for ascorbic acid (AA), dopamine (DA), uric acid (UA), and hydrochlorothiazide (HCTZ). The vertically stacked graphene sheets facilitated the electron transfer and reactant transport with a unique porous surface, high surface area, and high electron transport network of CVD graphene sheets. The TiC nanorod array facilitated the electron transfer and firmly held the graphene layer. Thus, the graphene/TiC nanorod arrays could simultaneously respond to trace biomarkers and antihypertensive drugs.


Assuntos
Técnicas Eletroquímicas , Grafite/química , Nanotubos/química , Compostos Orgânicos/análise , Titânio/química , Ácido Ascórbico/análise , Dopamina/análise , Técnicas Eletroquímicas/instrumentação , Hidroclorotiazida/análise , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanotubos/ultraestrutura , Espectroscopia Fotoeletrônica , Porosidade , Análise Espectral Raman , Propriedades de Superfície , Ácido Úrico/análise , Difração de Raios X
13.
ACS Appl Mater Interfaces ; 7(41): 22858-67, 2015 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-26421883

RESUMO

This paper presents a novel and versatile method for the fabrication of half nanotubes (HNTs) using a flexible template-based nanofabrication method denoted as electrochemical imprinting. With use of this method, polycrystalline nickel and nickel(II) oxide (Ni-NiO) HNTs were synthesized using pulsed electrodeposition to transfer Ni, deposited by radio frequency magnetron sputtering on a porous polytetrafluoroethylene template, onto a boron-doped diamond (BDD) film. The Ni-NiO HNTs exhibited semicircular profiles along their entire lengths, with outer diameters of 50-120 nm and inner diameters of 20-50 nm. The HNT walls were formed of Ni and NiO nanoparticles. A biosensor for the detection of L-serine was fabricated using a BDD electrode modified with Ni-NiO HNTs, and the device demonstrated satisfactory analytical performance with high sensitivity (0.33 µA µM(-1)) and a low limit of detection (0.1 µM). The biosensor also exhibited very good reproducibility and stability, as well as a high anti-interference ability against amino acids such as L-leucine, L-tryptophan, L-cysteine, L-phenylalanine, L-arginine, and L-lysine.


Assuntos
Boro/química , Diamante/química , Eletroquímica/métodos , Impressão Molecular , Nanotubos/química , Níquel/química , Serina/análise , Cristalização , Espectroscopia Dielétrica , Eletrodos , Nanotubos/ultraestrutura
14.
Nanoscale Res Lett ; 10: 39, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25852336

RESUMO

Further performance improvement is necessary for resistive random access memory (RRAM) to realize its commercialization. In this work, a novel pulse operation method is proposed to improve the performance of RRAM based on Ti/HfO2/Pt structure. In the DC voltage sweep of the RRAM device, the SET transition is abrupt under positive bias. If current sweep with positive bias is utilized in SET process, the SET switching will become gradual, so SET is current controlled. In the negative voltage sweep for RESET process, the change of current with applied voltage is gradual, so RESET is voltage controlled. Current sweep SET and voltage sweep RESET shows better controllability on the parameter variation. Considering the SET/RESET characteristics in DC sweep, in the corresponding pulse operation, the width and height of the pulse series can be adjusted to control the SET and RESET process, respectively. Our new method is different from the traditional pulse operation in which both the width and height of program/erase pulse are simply kept constant which would lead to unnecessary damage to the device. In our new method, in each program or erase operation, a series of pulses with the width/height gradually increased are made use of to fully finish the SET/RESET switching but no excessive stress is generated at the same time, so width/height-controlled accurate SET/RESET can be achieved. Through the operation, the uniformity and endurance of the RRAM device has been significantly improved.

15.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 6): o1300, 2010 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-21579397

RESUMO

In the title Schiff base compound, C(12)H(15)N(3)O(2), obtained from a condensation reaction of cyclo-hexa-none and 2-nitro-phenyl-hydrazine, the phenyl-hydrazone group is planar, the largest deviation from the mean plane being 0.0252 (12) Å, and the nitro fragment is twisted slightly with respect to the mean plane, making a dihedral angle of 6.96 (17)°. The cyclo-heaxanone ring displays a chair conformation. An intra-molecular N-H⋯O hydrogen bond helps to stabilize the mol-ecular structure.

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