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1.
Mater Sci Eng C Mater Biol Appl ; 110: 110747, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32204052

RESUMO

The preparation of Pt/cerium oxide and highly ordered mesoporous carbon (Pt/CeO2/OMC) nanohybrids is reported. CeO2 can be used as an active material that enhances the electrocatalytic properties of Pt nanoparticles. OMC exhibits excellent electrical conductivity and large specific surface area, which makes it a highly promising electrocatalyst support. Benefiting from the synergistic effects of the catalytic performance of Pt/CeO2 and excellent conductivity of OMC supports, the new nanocomposite of Pt/CeO2/OMC are able to create novel features of electrocatalytic activities. Pt/CeO2/OMC tri-component composite was used as an excellent sensing platform for the determination of adrenaline. The developed sensor exhibited excellent activity and convincing analytical performance towards adrenaline, such as wide linear range, high sensitivity, low limit of detection, and low limit of quantification. In addition, the recoveries ranging from 93.4 to 103.6% were obtained in human serum samples. The successful preparation of Pt/CeO2/OMC tri-component composite may promote the development of novel electrocatalyst and facilitate the design of new electrochemical sensors.

2.
J Colloid Interface Sci ; 560: 1-10, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31630023

RESUMO

Glucose is a popular biosensor target due to its closely with diabetes or hypoglycemia in blood. Designing efficiency electrocatalysts for the determination of glucose is vital to develop glucose detection devices. CoMoO4, as a kind of bimetallic oxide material, exhibits unique electrochemical properties. 3D macroporous carbon (MPC) has large specific surface area and excellent electrical conductivity, providing an effective support for loading other nano-entities to form novel composite with good synergetic effects. Herein, nanorod-like CoMoO4 anchored onto MPC support was synthesized for the development of a promising electrochemical sensing platform for glucose. Attributing to the synergic effects between the good electrocatalytic performance of CoMoO4 nanorods and the extraordinary electrical conductivity of 3D layered MPC, the novel CoMoO4/MPC composites non-enzymatic sensor shows excellent electrocatalytic performance for oxidation of glucose. Under the optimum conditions, the proposed CoMoO4/MPC hybrids provided a reliable linear range of 5 × 10-7 to 1.08 × 10-4 M with a low limit of detection (0.13 µM) for the detection of glucose. Meanwhile, the CoMoO4/MPC sensing platform shows fast response time of 1.76 s, good stability and selectivity for detecting glucose. Moreover, this non-enzymatic sensor also has been successfully applied to measure glucose level in human blood samples. Therefore, the developed sensor holds a new promise for the construction of facile and sensitive non-enzymatic glucose analytical platform.

3.
Biosens Bioelectron ; 148: 111834, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31706175

RESUMO

Efficient platforms for detecting telomerase activity are essential for early tumor monitoring and diagnosis. Herein, an enzyme-free electroanalytical strategy was developed for reliable and highly sensitive telomerase activity assay based on the increased electrochemical signals of methylene blue (MB) catalyzed by well monodisperse Au nanorods (AuNRs). In the presence of dNTPs and telomerase extracts, the assistant DNA 1 in the double stranded DNA can be extended to telomere repeat units (TTAGGG)n, which could form a hairpin structure by telomerase-triggered extension. The assistant DNA 2 was ingeniously dissociated from the double stranded DNA to combine with capture DNA. As a result, a large amount of AuNRs could be anchored on the surface of these sequences and used for electrocatalytic oxidation of MB. The developed biosensor showed a low limit of detection of 8.20 HeLa cells mL-1 and a wide dynamic range from 30 to 1.04 × 107 HeLa cells mL-1 for the determination of telomerase activity, which can provide a new way for telomerase activity assays in early diagnosis for cancers.

4.
J Colloid Interface Sci ; 563: 189-196, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31874306

RESUMO

The development of highly efficient, stable, and low-cost non-noble-metal electrocatalysts for oxygen evolution reactions (OER) is a major challenge for facilitate the efficiency of green energy storage. Bimetallic oxides are considered promising candidates as the electrocatalysts for OER because of their remarkable electrocatalytic activity, good stability, and low cost. In this work, ZIF-67 precursors were prepared via microwave irradiation and used as a self-sacrificing template. We proposed a rapid and scalable strategy to prepare Fe, Co bimetal embedded nanoporous carbon (Fe-Co/NPC) polyhedron composites by thermal decomposition of Fe species incorporated ZIF-67 precursor. Benefiting from the distinctive 3D polyhedron structural and compositional advantages, Fe-Co/NPC with hierarchical porous structure showed excellent electrochemical performance as ideal electrode material for OER. The resulting Fe-Co/NPC displayed outstanding electrocatalytic activity for OER with appreciable onset potential (1.59 V (vs. RHE)), small Tafel slope (53.55 mV dec-1), low over-potential (396 mV) to reach 10 mA cm-2, and excellent durability with negligible loss in current density after 1000 cycles. The current work demonstrated new insight into the design and construction of 3D structured Fe-Co/NPC polyhedron catalysts with highly electrocatalytic activity and good stability for electrocatalysis applications.

5.
J Colloid Interface Sci ; 549: 98-104, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31026767

RESUMO

Hydrazine is a possible human carcinogen because of its hyper toxicity. Therefore, the determination of hydrazine is particularly important for environmental protection and public security. Electrochemical method for the detection of hydrazine has drawn great interests because of its high sensitivity, fast response time, simple operation, and low cost. In this work, a leaf-like copper oxide (CuO) anchored onto wormlike ordered mesoporous carbon (OMC) composite was prepared for the construction of an electrochemical sensing platform for hydrazine. Because of the synergetic catalytic effect and unique structural properties, the obtained nanosized CuO incorporated in OMC exhibited good electrocatalytic performance for the oxidation of hydrazine with a catalytic rate constant (kcat) of 1.28 × 105 M-1s-1. Moreover, the content ratio of CuO: OMC was optimized to improve the electrocatalytic performance. The CuO/OMC hybrids can act as a sensitive and effective sensing platform for the determination of hydrazine, exhibiting wide linear range, high sensitivity, low limit of detection, and good stability. This comprehensive and systematic study may provide great opportunities for the design and construction of electrochemical sensors for environmental monitoring.

6.
Biosens Bioelectron ; 124-125: 53-58, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30343156

RESUMO

An electrochemical biosensor was designed for the determination of telomerase activity using an enzyme-free, PCR-free, and convenient electrochemical strategy. In this work, the electrochemical biosensor was constructed through the functionalization of Au nanorods with a carboxylic group (AuNRs-3) and subsequent immobilization with capture DNA (cDNA) for sensing telomerase activity. Upon telomerase triggered extension, the telomerase activity is related to the amount of the adsorbed electrocatalyst, leading to the different electrochemical signals for readout. Integrating with the efficient electrocatalysis of AuNRs-3-cDNA towards oxidation of acetaminophen, the prepared biosensor exhibits a wide dynamic correlation of telomerase activity from 1 × 102 to 1.04 × 107 HeLa cells mL-1 with a sensitivity of 2.68 HeLa cell mL-1 and the limit of detection was calculated to be 52.81 HeLa cells mL-1 under the optimal experimental conditions. Furthermore, the application of this electrochemical biosensor would provide the great potential for analysis of telomerase activity, revealing a powerful platform for early diagnosis of cancers.


Assuntos
Acetaminofen/química , Técnicas Biossensoriais , Técnicas Eletroquímicas , Telomerase/isolamento & purificação , Catálise , Ouro/química , Células HeLa , Humanos , Limite de Detecção , Nanotubos/química , Telomerase/química
7.
J Colloid Interface Sci ; 536: 424-430, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30380442

RESUMO

Pt nanoparticles immobilized on zirconium oxide (ZrO2) and porous carbons (Pt/ZrO2/PCs) tri-component nanohybrids derived from Pt/ metal-organic frameworks (MOFs) were synthesized. They were prepared by using Pt/MOFs as a template. Additionally, MOFs (UiO-66, a traditional MOFs) were used as ZrO2 and carbon sources without the need of additional precursors. The formation of these composite materials was confirmed through a comprehensive characterization such as transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The Pt/ZrO2/PCs show strong affinity toward the phosphate group and highly electrocatalytic activity for nitro compound on methyl parathion (MP) molecules. The high performance is owing to the combination of unique electrocatalytic activity of Pt species, excellent conductivity of PCs, and good adsorption properties of ZrO2 crystals for MP. The proposed Pt/ZrO2/PCs tri-component nanocomposite sensor realized the ultrasensitive detection of MP with a wide linear range between 3.8 × 10-9 and 1.14 × 10-2 mM and a low limit of detection of 1.45 × 10-9 mM. Therefore, it can be developed as an effective sensing platform for the detection of MP.

8.
Anal Chim Acta ; 1047: 28-35, 2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30567661

RESUMO

The preparation of palladium nanoparticles (Pd NPs) attached on nitrogen-doping hollow carbon spheres (NHCSs) surface using polyoxometalates (POMs) as both the reductant and bridging molecules by a green strategy was described in this paper. The samples have been thoroughly comprehensive characterized using scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, energy-dispersive X-ray spectra, and X-ray photoelectron spectroscopy. The as-prepared Pd/POMs/NHCSs tri-component nanohybrids provide enhanced electro-catalytic activities for oxidation of acetaminophen (AP) with the catalytic rate constant (kcat) of 2.34 × 103 M-1s-1 and diffusion coefficient (D) of 6.18 × 10-5 cm2s-1, because of the synergetic effects of Pd NPs and NHCSs. We assessed the use of Pd/POMs/NHCSs as an effective sensing template for electrochemical detection of AP, which showed high analytical performance, such as a linear range of 0.02 µM-0.63 µM with a sensitivity of 508.46 µAmM-1; a linear range of 0.63 µM to 0.083 mM with a sensitivity of 154.27 µAmM-1, and a low limit of detection of 3 nM. This strategy provides a new direction opportunity to promote the electrochemical performance of AP.


Assuntos
Acetaminofen/análise , Carbono/química , Nanopartículas Metálicas/química , Nanocompostos/química , Paládio/química , Compostos de Tungstênio/química , Acetaminofen/química , Técnicas Eletroquímicas/métodos , Limite de Detecção , Oxirredução
9.
Mater Sci Eng C Mater Biol Appl ; 95: 78-85, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30573273

RESUMO

Here we report an Au nanoparticles supported on nanostructured porous carbon (NPCs) hybrid through a coordination-assisted strategy. Metal-organic frameworks (MOFs) have been demonstrated as suitable precursors for preparing NPCs through the impregnation of a secondary carbon source within pores of MOFs. The thermal transformation of Au/UiO-66-NH2 composites in an inert atmosphere has yielded ultrafine Au-embedded NPCs (Au/NPCs). The formation of these composite materials was verified by a comprehensive characterization using X-ray diffraction, N2 adsorption, scanning electron microscopy, and transmission electron microscopy. Because of the unique structural properties and synergetic catalytic effect, Au/NPCs can be developed as an effective sensing platform for the detection of acetaminophen (AP), which showed high activity and excellent analytical performance towards AP, such as a wide linear range of 0.12-95.10 µM, a high sensitivity of 357.62 µA mM-1, and a low limit of detection of 49.4 nM. Importantly, the successfully fabricated Au/NPCs device accurately measured the amount of AP in pharmaceutical samples.


Assuntos
Acetaminofen/química , Técnicas Biossensoriais/métodos , Carbono/química , Técnicas Eletroquímicas/métodos , Catálise , Porosidade
10.
J Colloid Interface Sci ; 532: 650-656, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30119007

RESUMO

The construction of highly active and stable non-noble metal electrocatalysts for oxygen evolution reaction (OER) is a crucial requirement for green energy utilization. Herein, we report a novel hybrid nanostructure of Zn/Co bimetallic oxide (ZnxCo3-xO4) hollow polyhedron through a pyrolysis-oxidation strategy derived from bimetallic Zn, Co-zeolitic imidazolate frameworks (ZnCo-ZIFs) rhombic polyhedral. Benefiting from the synergistic effects between highly active metal oxide and the unique polyhedron structure, the ZnxCo3-xO4 hollow polyhedron hybrid displayed outstanding electrocatalytic performances in alkaline media. When the ZnxCo3-xO4 polyhedron was employed as electrocatalysts for OER, a potential as low as 1.66 V (vs. RHE) was required to deliver the current density of 10 mA cm-2 in 1 M KOH, and ZnxCo3-xO4 still presented superior activity after continuously working for cyclic voltammetric scanning of 1000 cycles.

11.
J Colloid Interface Sci ; 524: 1-7, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-29627667

RESUMO

Decoration of leaf-like zeolitic imidazolate framework (ZIF-L) with Au nanoparticles (NPs) by a simple self-assembly method was described in this work. The materials were characterized by Fourier transform infrared spectroscopy, energy-dispersive X-ray spectra, N2 adsorption, and thermogravimetric analysis. Acetaminophen (AP) is most commonly referred to as an over-the-counter antipyretic and analgesic, which is a key factor in relieving fever and pain. It is particular significant to take efforts and conduct research for the development of reliable methods to detect the AP. An electrochemical sensor for AP was constructed based on the Au/ZIF-L, which exhibited excellent electrocatalytic activity for the oxidation of AP with the catalytic rate constant (kcat) of 4.27 × 104 M-1 s-1 and diffusion coefficient (D) of of 8.31 × 10-5 cm2 s-1. Importantly, Au/ZIF-L was developed as an effective sensing platform for the detection of AP, which showed high analytical performance, such as a linear range of 3.50 µM-0.056 mM with sensitivity of 37.28 µA mM-1, a linear range of 0.056-0.56 mM with sensitivity of 25.10 µA mM-1, and a low limit of detection of 1.02 µM. The successfully fabricated Au/ZIF-L device can be used to accurately measure the amount of AP in pharmaceutical samples. Results implied the potential application of functionalized MOF composite materials in the field of electrocatalysis, making it particularly suitable for electroanalytical chemistry.

12.
Pharmacology ; 99(3-4): 188-195, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27889779

RESUMO

OBJECTIVE: To test the effects of Tanshinone IIA (Tan IIA) on cell viability, cycle, apoptosis, and autophagy of human glioma cell U251 by regulating phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signal pathway. METHODS: Tan IIA and PI3K agonist (740 Y-P) were used to treat glioma cells U251. MTT assay was used to assess cell viability and flow cytometry was used to detect cell apoptosis and cell cycle. The expressions of apoptosis-related proteins (Bcl-2 and Bax), autophagy-related proteins (LC3B and Beclin 1) and PI3K/Akt/mTOR signal pathway-associated proteins (p-PI3K, p-Akt and p-mTOR) were evaluated by Western blotting. RESULTS: Tan IIA decreased the expression of p-PI3K and p-Akt proteins, inhibited cell viability and promoted apoptosis. Meanwhile, the expression of Bax increased, while the expression of Bcl-2 decreased. In addition, Tan IIA promoted autophagy in U251 glioma cells and raised the expression of LC3B and Beclin 1. However, 740 Y-P played a reversed role of Tan IIA in cell viability, cycle, apoptosis, and autophagy of U251 cells. CONCLUSION: Tan IIA could suppress the viability of U251 cells and induce cell apoptosis and autophagy, which might be related to the inhibition of the PI3K/Akt/mTOR signal pathway.


Assuntos
/farmacologia , Apoptose/efeitos dos fármacos , Glioma , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Serina-Treonina Quinases TOR/antagonistas & inibidores , Anti-Inflamatórios não Esteroides/farmacologia , Apoptose/fisiologia , Autofagia/efeitos dos fármacos , Autofagia/fisiologia , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Glioma/metabolismo , Glioma/patologia , Humanos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Serina-Treonina Quinases TOR/metabolismo
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