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1.
Anal Chem ; 96(14): 5446-5454, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38556805

RESUMO

In this study, a novel integrated photoelectrochemical (PEC) sensor platform was proposed, utilizing an optical fiber (OF) as the working electrode for guided in situ light. A CdS quantum dots (QDs)/ZnO nanosheets (NSs) n-n heterojunction was quickly and easily constructed on the OF surface by successive ionic layer adsorption and reaction (SILAR). Au nanoparticles (NPs)@dsDNA as a capturing probe were modified on the CdS QDs/ZnO NSs@OF (CZ@OF). Due to the energy transfer between Au NPs@dsDNA and CdS QDs, the resultant opto-electrode has a lower background near zero, enabling the "signal-on" detection of biomarkers (interleukin-6 (IL-6) as a model). The OF-PEC biosensor demonstrated a wide linear range from 1 to 100 pg mL-1 with a regression coefficient (R2) of 0.9958 and an impressive detection limit (LOD) of 0.19 pg mL-1. More significantly, the proposed OF-PEC can be successfully used for the detection of IL-6 in serum samples from patients with pulmonary arterial hypertension, and it showed consistency and is more sensitive to trace concentrations compared to BD FACSCanto II flow cytometry used at the hospital. This holds significance for an early disease diagnosis. Therefore, the proposed OF-PEC not only achieves integration of the light source and sensing interface but also enables sensitive and accurate "signal-on" detection of IL-6. Furthermore, due to the flexibility and remote detection capabilities of OF, the application of OF-PEC is expected to be expanded more widely. This approach opens up possibilities for advances in PEC sensing.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Pontos Quânticos , Óxido de Zinco , Humanos , Técnicas Eletroquímicas , Citocinas , Interleucina-6 , Ouro , Adsorção , Fibras Ópticas , Eletrodos , Limite de Detecção
2.
Crit Rev Food Sci Nutr ; : 1-17, 2022 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-36579429

RESUMO

Our present knowledge about the efficacy of tea consumption in improving age-related cognitive disorders is incomplete since previous epidemiological studies provide inconsistent evidence. This unified systematic review and meta-analysis based on updated epidemiological cohort studies and randomized controlled trials (RCTs) evidence aimed to overcome the limitations of previous reviews by examining the efficacy of distinct types of tea consumption. PubMed, Embase, and MEDLINE were searched up to May 20, 2022, and 23 cohorts and 12 cross-sectional studies were included. Random-effects meta-analyses were conducted to obtain pooled RRs or mean differences with 95% CIs. The pooled RRs of the highest versus lowest tea consumption categories were 0.81 (95% CIs: 0.75-0.88) and 0.69 (95% CIs: 0.61-0.77), respectively. The pooled mean difference of four included RCTs revealed a beneficial effect of tea on cognitive dysfunction (MMSE ES: 1.03; 95% CI, 0.14-1.92). Subgroup analyses further demonstrated that green and black tea intake was associated with a lower risk of cognitive disorders in eastern countries, especially in women. The evidence quality was generally low to moderate. The present review provides insight into whether habitual tea consumption can be an effective approach against age-related neurodegenerative cognitive disorders and summarizes potential mechanisms based on currently published literature.

3.
Mikrochim Acta ; 188(8): 243, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34231032

RESUMO

The design and development of a 3D hierarchical CdS/NiO heterojunction and its application in a self-powered cathodic photoelectrochemical (PEC) bioanalysis is introduced. Specifically, NiO nanoflakes (NFs) were in situ formed on carbon fibers via a facile liquid-phase deposition method followed by an annealing step and subsequent integration with CdS quantum dots (QDs). The glucose oxidase (GOx) was then coated on the photocathode to allow the determination of glucose. Under 5 W 410 nm LED light and at a working voltage of 0.0 V (vs. Ag/AgCl), this method can assay glucose concentrations down to 1.77×10-9 M. The linear range was 5×10-7 M to 1×10-3 M, and the relative standard deviation (RSD) was below 5%. The photocathodic biosensor achieved target detection with high sensitivity and selectivity. This work is expected to stimulate more passion in the development of innovative hierarchical heterostructures for advanced self-powered photocathodic bioanalysis. Design of 3D hierarchical CdS/NiO heterojunction and its application in a self-powered cathodic photoelectrochemical (PEC) bioanalysis.


Assuntos
Compostos de Cádmio/química , Glucose Oxidase/metabolismo , Glucose/análise , Nanocompostos/química , Níquel/química , Sulfetos/química , Técnicas Biossensoriais , Fibra de Carbono , Técnicas Eletroquímicas , Limite de Detecção , Processos Fotoquímicos , Pontos Quânticos
4.
Anal Chim Acta ; 1143: 173-180, 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33384115

RESUMO

Herein, we describe a customized approach for facile preparation of three-dimensional (3D) NiO nanoflakes (NFs)/carbon fiber meshwork (CFM) and its validation as a common photocathode matrix for photoelectrochemical (PEC) bioanalysis, which to our knowledge has not been reported. Specifically, 3D NiO NFs/CFM was fabricated by a sequential liquid phase deposition and annealing process, which was then characterized by scanning electron microscopy, X-ray photoelectron spectrum, UV-vis absorption spectra and N2 adsorption-desorption measurement. Sensitized by BiOI and incorporated with an alkaline phosphatase (ALP)/tyrosinase (TYR) bi-enzyme cascade system, a sensitive split-type cathodic PEC bioanalysis for the determination of ALP was achieved. This method can detect ALP concentrations down to 3 × 10-5 U L-1 with a linear response range of 0.001-10 U L-1. Moreover, this proposed system exhibited good selectivity, stability and excellent performance for real sample analysis. This research features the facile preparation of 3D NiO NFs/CFM that could acts as a universal matrix for photocathodic analysis, and is envisioned to stimulate more effort for advanced 3D photocathode for PEC bioanalysis and beyond.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Fibra de Carbono , Eletrodos , Processos Fotoquímicos
5.
RSC Adv ; 10(47): 28026-28031, 2020 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35519092

RESUMO

A novel voltammetric sensor was designed and used for the determination of l-tyrosine (l-Tyr) by surface modification of a glassy carbon electrode with reduced graphene oxide-hemin-Ag (rGO-H-Ag) nanocomposites. The nanocomposites were synthesized by a facile one-pot hydrothermal method and characterized by means of transmission electron microscopy and Raman spectroscopy. The determination of l-Tyr was investigated by cyclic voltammetry and further quantified using differential pulse voltammetry. The results revealed a significant enhanced electrochemical oxidation effect for l-Tyr at the nanocomposites modified electrode. Two linear ranges from 0.1 to 100 µM and 100 to 1000 µM as well as a low detection limit of 30 nM (S/N = 3) were obtained. In addition, the sensor also demonstrated good selectivity, reproducibility and stability.

6.
Analyst ; 144(13): 3967-3971, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31140474

RESUMO

An OFF-ON detection method for Cu2+ was developed at the AgAu bimetallic nanoparticle decorated nitrogen-doped graphene (AgAu-NG) nanocomposite modified electrode. The measurement was based on the copper-catalyzed oxidation of cysteamine (Cys) to regulate the oxidation peak current of Ag. In the absence of Cu2+, Cys can bind to the surface of AgAu-NG via the Ag-S or Au-S bond, thus leading to an obvious decrease of the oxidation peak current of Ag. However, in the presence of Cu2+, Cu2+ can greatly catalyze the oxidation of Cys by dissolved O2 to form cystamine, which would fall off the surface of AgAu-NG nanocomposites, leading to the partial recovery of the oxidation peak current of Ag. With the increase in the concentration of Cu2+, the oxidation peak current of Ag in the presence of Cys increases accordingly. So, the concentration of Cu2+ can be measured. By using the optimum conditions, this method can detect Cu2+ concentrations down to 0.3 nM (S/N = 3) with a linear response range of 1 nM-1 mM. Furthermore, this method was applied to determine Cu2+ concentrations in river water samples and showed excellent analytical performance.

7.
J Pharm Biomed Anal ; 52(4): 550-6, 2010 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-20138454

RESUMO

S-1 is an oral anticancer drug, which consists of tegafur (FT), gimeracil (CDHP) and potassium oxonate (Oxo) at a molar ratio of 1:0.4:1. Among these, tegafur is a prodrug, and is rapidly metabolized to the active drug, 5-fluorouracil (5-FU), in vivo. To evaluate the pharmacokinetics of S-1 in patients, LC-MS/MS methods were developed and validated for determination of FT, 5-FU, CDHP and Oxo in human plasma. FT, 5-FU and CDHP were extracted from plasma following protein precipitation, separated on a Synergi Hydro-RP column and simultaneously quantified by LC-MS/MS. The mobile phase consisted of methanol-water-ammonia-acetic acid (27:73:0.0018:0.018, v/v/v/v). The mass spectrometer was operated in negative mode using electrospray ionization. The calibration curves were linear in the range of 12.0-3000ng/mL for FT, and 2.00-500ng/mL for 5-FU and CDHP. The accuracy ranged from 93.1% to 110.7% and the precision ranged from 2.4% to 14.6% for each analyte. To determine Oxo in human plasma, an LC-MS/MS method employing pre-column derivatization was developed and validated. 4-Bromomethyl-7-methoxycoumarin was chosen as the derivatization reagent and [(13)C(2),(15)N(3)]-Oxo was used as the internal standard. The MS/MS detection was operated in positive mode using an APCI source. The calibration range was 2.00-150ng/mL. The accuracy and precision were within 95.9-99.1% and 4.4-10.0%, respectively. The validated methods were successfully applied to characterize the pharmacokinetic profiles of FT, 5-FU, CDHP and Oxo following oral administration of 60mg S-1 tablets to patients with solid gastrointestinal tract tumors.


Assuntos
Fluoruracila/sangue , Ácido Oxônico/sangue , Piridinas/sangue , Espectrometria de Massas em Tandem , Tegafur/sangue , Cromatografia Líquida/métodos , Humanos , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
8.
Yi Chuan Xue Bao ; 31(4): 349-56, 2004 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-15487502

RESUMO

The sequences of nrDNA regions of 17 species and Phyllostachys edulis (outgroup) sampled, which are of represent and type species for different taxa in the genus Arundinaria,were analyzed by PCR amplification and direct DNA sequencing. The phylogenetic trees generated from maximum parsimony analysis showed that the sampled bamboos were naturally monophletic, appearing that these species of the bamboos belong to the genus Arundinaria. The internal transcribed spacers (ITS) data indicated that the species were divided into two branches, one including A. oleosa, A. hsienchuensis, A. chino, A. amara, A. yixingensis, A. amabilis, A. fortunei, and A. pygmaea, the other including A. graminea, A. fargesii, A. faberi, A. hupehensis, Pseudosasa japonica cv. Tsutsumiana, P. japonica, Brachystachyum densiflorum, A. oedogonata, and A. sulcata. The result also showed that there was close relationship between A. graminea and A. fargesii, Pseudosasa japonica cv. Tsutsumiana and P. japonica, A. sulcata, Brachystachyum densiflorum and A. oedogonata, (99%, 100% and 82% boot-strap support respectively). Moreover, there was very close relationship between A. amabilis and A. hsienchuensis, indicating that A. amabilis belongs to the genus Arundinaria. It was shown in the phylogenetic tree that A. pygmaea and A. fortunei had close relationship, and were a sister branch to the bamboos of Pleioblastus.


Assuntos
DNA de Plantas/química , DNA Espaçador Ribossômico/química , Plantas/classificação , Sequência de Bases , Filogenia , Plantas/genética
9.
Yi Chuan Xue Bao ; 29(6): 549-54, 2002 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-12096635

RESUMO

Xinjiang is a center of distribution and differentiation of genus Dianthus in China, and has a great deal of species resources. The sequences of ITS region (including ITS-1, 5.8S rDNA and ITS-2) of nuclear ribosomal DNA from 8 species of genus Dianthus wildly distributed in Xinjiang were determined by direct sequencing of PCR products. The result showed that the size of the ITS of Dianthus is from 617 to 621 bp, and the length variation is only 4 bp. There are very high homogeneous (97.6%-99.8%) sequences between species, and about 80% homogeneous sequences between genus Dianthus and outgroup. The sequences of ITS in genus Dianthus are relatively conservative. In general, there are more conversion than transition in the variation sites among genus Dianthus. The conversion rates are relatively high, and the ratios of conversion/transition are 1.0-3.0. On the basis of phylogenetic analysis of nucleotide sequences the species of Dianthus in China would be divided into three sections. There is a distant relationship between sect. Barbulatum Williams and sect. Dianthus and between sect. Barbulatum Williams and sect. Fimbriatum Williams, and there is a close relationship between sect. Dianthus and sect. Fimbriatum Williams. From the phylogenetic tree of ITS it was found that the origin of sect. Dianthusis is earlier than that of sect. Fimbriatum Williams and sect. Barbulatum Williams.


Assuntos
Elementos de DNA Transponíveis , DNA de Plantas , DNA Ribossômico , Dianthus/genética , Núcleo Celular , China , DNA de Plantas/análise , DNA Ribossômico/análise , Dianthus/classificação , Evolução Molecular , Filogenia , Análise de Sequência de DNA
10.
Yi Chuan Xue Bao ; 29(10): 915-21, 2002 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-12561478

RESUMO

The fingerprints of 13 species in genus Lycoris were generated by use of RAPD method. Forty-one primers were screened from 520 random primers, and a total of 350 DNA fragments were amplified ranging from 0.3-3.0 kb, 253 (72.3%) of which were polymorphic. The average number of DNA band produced by each primer was 6.2. Nei's similarity coefficients and genetic distances were calculated by use of the software of TFPGA version 1.3 and dendrogram of Lycoris was constructed using UPGMA. It is indicated that the 13 species of the genus Lycoris were divided into two groups, and five species of the genus including L. rosea, L. haywardii, L. straminea, L. sprengeri and L. radiata with monotype karyotypes (I-shaped) were clustered together respectively. The basic chromosome number was x = 11. The others which have two-types karyotypes (I-shaped and V-shaped) were clustered together respectively. They were L. houdyshelii, L. albiflora, L. chinensis, L. longituba, L. anhuiensis, L. squmigera, L. caldwellii and L. aurea. The closest relationship was between L. rosea and L. haywardii. L. radiata is highly divergent from L. aurea. The results were in consistence with that of the analysis of chromosome karyotype. The present paper discussed the problems whether L. rosea, L. haywardii and L. stramina originated as natural hybrids and taxonomy position of L. albiflora, L. straminea and L. houdyshelii based on the RAPD analysis.


Assuntos
Lycoris/genética , Filogenia , DNA de Plantas/genética , Lycoris/classificação , Técnica de Amplificação ao Acaso de DNA Polimórfico , Especificidade da Espécie
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