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1.
J Orthop Surg Res ; 18(1): 811, 2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37904187

RESUMO

PURPOSE: In osteoporosis, the balance between osteogenic and adipogenic differentiation of mesenchymal stem cells (MSCs) is disrupted. The osteogenic differentiation of bone marrow MSCs (BMSCs) is important for improving osteoporosis. The aim of this study was to explore the role and molecular mechanism of miR-210 in the balance of osteogenic/adipogenic differentiation of BMSCs in postmenopausal osteoporosis. METHODS: Postmenopausal osteoporosis rat models were constructed by ovariectomy (OVX). BMSCs were isolated from the femur in rats of Sham and OVX groups. MiR-210 was overexpressed and suppressed by miR-210 mimics and inhibitor, respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the relative mRNA expression of miR-210, ephrin type-A receptor 2 (EPHA2), alkaline phosphatase (ALP), osterix (OSX), osteocalcin (Bglap), Runt-related transcription factor 2 (Runx2), peroxisome proliferator activated receptor gamma, and fatty acid binding protein 4 (FABP4) in each group of rat femoral tissues or BMSCs. Western blot was applied to detect the protein expression level of EPHA2 in rat femoral tissues and cells. Alizarin red S staining and oil red O staining were performed to assess the osteogenic and adipogenic differentiation of BMSCs, respectively. In addition, the targeting relationship between miR-210 and EPHA2 was verified by a dual luciferase gene reporter assay. RESULTS: The expression of miR-210 was significantly reduced in femoral tissues and BMSCs of OVX rats, and its low expression was associated with reduced bone formation. The osteogenic differentiation was enhanced in OVX rats treated with miR-210 mimic. Overexpression of miR-210 in transfected BMSCs was also found to significantly promote osteogenic differentiation and even inhibit adipogenic differentiation in BMSCs, while knockdown of miR-210 did the opposite. Further mechanistic studies showed that miR-210 could target and inhibit the expression of EPHA2 in BMSCs, thus promoting osteogenic differentiation and inhibiting adipogenic differentiation of BMSCs. CONCLUSION: MiR-210 promotes osteogenic differentiation and inhibits adipogenic differentiation of BMSCs by down-regulating EPHA2 expression. As it plays an important role in the osteogenic/adipogenic differentiation of osteoporosis, miR-210 can serve as a potential miRNA biomarker for osteoporosis.


Assuntos
Células-Tronco Mesenquimais , MicroRNAs , Osteoporose Pós-Menopausa , Osteoporose , Animais , Feminino , Ratos , Células da Medula Óssea/metabolismo , Diferenciação Celular/genética , Células Cultivadas , Regulação para Baixo , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/metabolismo , Osteogênese/genética , Osteoporose/genética , Osteoporose Pós-Menopausa/genética , Osteoporose Pós-Menopausa/metabolismo , Receptor EphA2/metabolismo
2.
Drug Deliv Transl Res ; 13(11): 2819-2833, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37160629

RESUMO

The objective of this study was to develop phospholipid-based injectable phase transition in situ gels (PTIGs) for the sustained release of Brexpiprazole (Brex). Phospholipid (Lipoid S100, S100) and stearic acid (SA) were used as the gel matrix which was dissolved in biocompatible solvent medium-chain triglyceride (MCT), N-methyl pyrrolidone (NMP), and ethanol to obtain PTIGs solution. The Brex PTIG showed a solution condition of low viscosity in vitro and was gelatinized in situ in vivo after subcutaneous injection. Both in vitro release assay and in vivo pharmacokinetics study in SD rats displayed that Brex in PTIGs could achieve a sustained release, compared with brexpiprazole solution (Brex-Sol) or brexpiprazole suspension (Brex-Sus). The Brex-PTIGs had good degradability and biocompatibility in vivo with rare inflammation at the injection site. Among the three Brex-PTIG formulations, Brex-PTIG-3 with the SA in the formulation had the greatest gelation viscosity, the lowest initial release rate, and the most stable release profile with sustained release of up to 60 days. The above results indicated that, as a novel drug delivery system, the Brex-PTIGs offered a new option for the clinical treatment of patients with schizophrenia.


Assuntos
Fosfolipídeos , Ratos , Humanos , Animais , Preparações de Ação Retardada/farmacocinética , Ratos Sprague-Dawley , Géis , Viscosidade
3.
BMC Musculoskelet Disord ; 24(1): 393, 2023 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-37198572

RESUMO

BACKGROUND: To explore the effect and mechanism of action of miR-210 on postmenopausal osteoporosis (PMPO) in ovariectomized rats in vivo. METHODS: An ovariectomized (OVX) rat model was established by ovariectomy. Tail vein injection was performed to overexpress and knock down miR-210 in OVX rats, followed by the collection of blood and femoral tissues from each group of rats. And quantitative real-time polymerase chain reaction (qRT-PCR) was applied to assess the expression level of miR-210 in femoral tissues of each group. Micro computed tomography (Micro CT) was adopted to scan the microstructure of the femoral trabecula in each group to obtain relevant data like bone mineral density (BMD), bone mineral content (BMC), trabecular bone volume fraction (BV/TV), trabecular thickness (Tb.Th), bone surface-to-volume ratio (BS/BV), and trabecular separation (Tb.Sp). ELISA was used for determining the level of bone alkaline phosphatase (BALP), amino-terminal propeptide of type I procollagen (PINP), osteocalcin (OCN), and C-terminal telopeptide of type I collagen (CTX-1) in serum; and Western blot for the protein level of Runt-related transcription factor 2 (Runx2), osteopontin (OPN), and collagen type I alpha 1 (COL1A1) in femoral tissues. RESULTS: MiR-210 expression was significantly decreased in femoral tissues of OVX rats. Overexpression of miR-210 could obviously increase BMD, BMC, BV/TV and Tb.Th, whereas significantly decrease BS/BV and Tb.Sp in femurs of OVX rats. Moreover, miR-210 also downregulated BALP and CTX-1 level, upregulated PINP and OCN level in the serum of OVX rats promoted the expression of osteogenesis-related markers (Runx2, OPN and COL1A1) in the femur of OVX rats. Additionally, further pathway analysis revealed that high expression of miR-210 activated the vascular endothelial growth factor (VEGF)/Notch1 signaling pathway in the femur of OVX rats. CONCLUSION: High expression of miR-210 may improve the micromorphology of bone tissue and modulate bone formation and resorption in OVX rats by activating the VEGF/Notch1 signaling pathway, thereby alleviating osteoporosis. Consequently, miR-210 can serve as a biomarker for the diagnosis and treatment of osteoporosis in postmenopausal rats.


Assuntos
MicroRNAs , Osteoporose Pós-Menopausa , Osteoporose , Animais , Feminino , Ratos , Densidade Óssea , Subunidade alfa 1 de Fator de Ligação ao Core/farmacologia , Osteoporose/metabolismo , Osteoporose Pós-Menopausa/diagnóstico por imagem , Osteoporose Pós-Menopausa/genética , Ovariectomia , Ratos Sprague-Dawley , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/farmacologia , Microtomografia por Raio-X
4.
Front Immunol ; 14: 1136051, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37090696

RESUMO

Interferon (IFN), the most effective antiviral cytokine, is involved in innate and adaptive immune responses and is essential to the host defense against virus invasion. Once the host was infected by pathogens, the pathogen-associated molecular patterns (PAMPs) were recognized by the host pattern recognition receptors (PRRs), which activates interferon regulatory transcription factors (IRFs) and nuclear factor-kappa B (NF-κB) signal transduction pathway to induce IFN expression. Pathogens have acquired many strategies to escape the IFN-mediated antiviral immune response. Pestiviruses cause massive economic losses in the livestock industry worldwide every year. The immune escape strategies acquired by pestiviruses during evolution are among the major difficulties in its control. Previous experiments indicated that Erns, as an envelope glycoprotein unique to pestiviruses with RNase activity, could cleave viral ss- and dsRNAs, therefore inhibiting the host IFN production induced by viral ss- and dsRNAs. In contrast, Npro, the other envelope glycoprotein unique to pestiviruses, mainly stimulates the degradation of transcription factor IRF-3 to confront the IFN response. This review mainly summarized the current progress on mechanisms mediated by Npro of pestiviruses to antagonize IFN production.


Assuntos
Evasão da Resposta Imune , Pestivirus , Pestivirus/genética , Pestivirus/metabolismo , Interferons/metabolismo , NF-kappa B/metabolismo , Antivirais , Fatores Reguladores de Interferon/metabolismo , Glicoproteínas/metabolismo
5.
Front Vet Sci ; 9: 930123, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35873677

RESUMO

Porcine parvoviruses (PPV) and porcine circoviruses type 2 (PCV2) are widespread in the pig population. Recently, it was suggested that PPV7 may stimulate PCV2 and PCV3 replication. The present study aimed to make detection and molecular characterization of PPV7 for the first time in eastern Inner Mongolia Autonomous Region, China. Twenty-seven of ninety-four samples (28.72%) and five in eight pig farms were PPV7 positive. Further detection showed that the co-infection rate of PPV7 and PCV2 was 20.21% (19/94), and 9.59% (9/94) for PPV7 and PCV3. In addition, the positive rate of PPV7 in PCV2 positive samples was higher than that in PCV2 negative samples, supporting that PCV2 could act as a co-factor for PPV7 infection. In total, four PPV7 strains were sequenced and designated as NM-14, NM-19, NM-4, and NM-40. The amplified genome sequence of NM-14 and NM-40 were 3,999nt in length, while NM-19 and NM-4 were 3,996nt with a three nucleotides deletion at 3,097-3,099, resulting in an amino acid deletion in the Cap protein. Phylogenetic analysis based on the capsid amino acid (aa) sequences showed that 52 PPV7 strains were divided into two clades, and the four PPV7 strains in this study were all clustered in clade 1. The genome and capsid amino acid sequence of the four PPV7 strains identified in this study shared 80.0-96.9% and 85.9-100% similarity with that of 48 PPV7 reference strains selected in NCBI. Simplot analysis revealed that NM-19 and NM-4 strains were probably produced by recombination of two PPV7 strains from China. The amino acid sequence alignment analysis of capsid revealed that the four PPV7 strains detected in Inner Mongolia had multiple amino acid mutations in the 6 B cell linear epitopes compared with the reference strains, suggesting that the four PPV7 strains may have different characteristics in receptor binding and immunogenicity. In summary, this paper reported the PPV7 infection and molecular characterization in the eastern of Inner Mongolia Autonomous Region for the first time, which is helpful to understand the molecular epidemic characteristics of PPV7.

6.
Clin Exp Rheumatol ; 39 Suppl 133(6): 23-29, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34251320

RESUMO

OBJECTIVES: At present, the pathogenesis of Sjögren's syndrome (SS) remains unclear. This research aimed to identify differential metabolites that contribute to SS diagnosis and discover the disturbed metabolic pathways. METHODS: Recent advances in mass spectrometry have allowed the identification of hundreds of unique metabolic signatures and the exploration of altered metabolite profiles in disease. In this study, 505 candidates including healthy controls (HCs) and SS patients were recruited and the serum samples were collected. A non-targeted gas chromatography-mass spectrometry (GC-MS) serum metabolomics method was used to explore the changes in serum metabolites. RESULTS: We found SS patients and HCs can be distinguished by 21 significant metabolites. The levels of alanine, tryptophan, glycolic acid, pelargonic acid, cis-1-2-dihydro-1-2-naphthalenediol, diglycerol, capric acid, turanose, behenic acid, dehydroabietic acid, stearic acid, linoleic acid, heptadecanoic acid, valine, and lactic acid were increased in serum samples from SS patients, whereas levels of catechol, anabasine, 3-6-anhydro-D-galactose, beta-gentiobiose, 2-ketoisocaproic acid and ethanolamine were decreased. The significantly changed pathways included the following: Linoleic acid metabolism; unsaturated fatty acid biosynthesis; aminoacyl-tRNA biosynthesis; valine, leucine, and isoleucine biosynthesis; glycerolipid metabolism; selenocompound metabolism; galactose metabolism; alanine, aspartate and glutamate metabolism; glyoxylate and dicarboxylate metabolism; glycerophospholipid metabolism; and valine, leucine and isoleucine degradation. CONCLUSIONS: These findings enhance the informative capacity of biochemical analyses through the identification of serum biomarkers and the analysis of metabolic pathways and contribute to an improved understanding of the pathogenesis of SS.


Assuntos
Síndrome de Sjogren , Biomarcadores , Humanos , Metabolômica , Síndrome de Sjogren/diagnóstico
7.
J Ethnopharmacol ; 274: 113997, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-33705918

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Ginseng is a valuable medicinal herb used in China for the prevention and treatment of cancer, diabetes, cardiovascular diseases and other diseases. As the main active ingredient of ginseng, ginsenoside has a wide range of pharmacological effects. Ginsenoside Rh2, a protopanaxadiol saponin from ginseng, exhibits anti-inflammatory and anticancer effects. AIM OF THE STUDY: The potential biological mechanism of Rh2 in the treatment of ulcerative colitis (UC) has not been clarified clearly. In our research, we aimed to explore the therapeutic effects of Rh2 on dextran sodium sulfate (DSS)-induced colitis and elucidate the mechanism of Rh2 in treating UC. METHODS: DSS-induced UC mice were established and randomly divided into the following four groups: control group, DSS group, Rh2 (50 mg/kg) group and sulfasalazine (SASP, 200 mg/kg) group. Except for the control group, 3% DSS drinking water was given to each group for 7 days, and the other two groups were intragastrically administered with Rh2 and SASP for 10 days. At the end of the experiment, colon samples were collected, and phenotypic and pathological analyses were performed in UC mice. Then, Western blot, immunohistochemistry and quantitative real-time PCR analyses were performed to determine the expression of signaling pathway-related factors. RESULTS: Rh2 markedly alleviated DSS-induced body weight loss, intestinal damage, colon length shortening and disease activity index (DAI) scores. Furthermore, proinflammatory cytokines, such as TNF-α, IL-6 and IL-1ß, were reduced by Rh2. Additionally, STAT3/miR-214 activation was also suppressed by Rh2 administration. In vitro, we demonstrated that Rh2 effectively inhibited IL-6-induced STAT3 phosphorylation and miR-214 expression in cultured normal colonic epithelial cells. CONCLUSION: Our results suggested that Rh2 exhibits potential application value in the treatment of UC, and its mechanism is related to the downregulation of STAT3/miR-214 levels, which is expected to be applicable in the treatment of clinical UC.


Assuntos
Anti-Inflamatórios/farmacologia , Colite Ulcerativa/tratamento farmacológico , Ginsenosídeos/farmacologia , MicroRNAs/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Anti-Inflamatórios/uso terapêutico , Linhagem Celular , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/metabolismo , Colite Ulcerativa/patologia , Citocinas/metabolismo , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Ginsenosídeos/química , Ginsenosídeos/uso terapêutico , Humanos , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Masculino , Camundongos Endogâmicos C57BL , MicroRNAs/antagonistas & inibidores , Fator de Transcrição STAT3/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Sulfassalazina/farmacologia , Sulfassalazina/uso terapêutico
8.
Rheumatology (Oxford) ; 60(3): 1252-1259, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32911538

RESUMO

OBJECTIVE: The relationship between serum lipid variations in SS and healthy controls was investigated to identify potential predictive lipid biomarkers. METHODS: Serum samples from 230 SS patients and 240 healthy controls were collected. The samples were analysed by ultrahigh-performance liquid chromatography coupled with Q Exactive™ spectrometry. Potential lipid biomarkers were screened through orthogonal projection to latent structures discriminant analysis and further evaluated by receiver operating characteristic analysis. RESULTS: A panel of three metabolites [phosphatidylcholine (18:0/22:5), triglyceride (16:0/18:0/18:1) and acylcarnitine (12:0)] was identified as a specific biomarker of SS. The receiver operating characteristic analysis showed that the panel had a sensitivity of 84.3% with a specificity of 74.8% in discriminating patients with SS from healthy controls. CONCLUSION: Our approach successfully identified serum biomarkers associated with SS patients. The potential lipid biomarkers indicated that SS metabolic disturbance might be associated with oxidized lipids, fatty acid oxidation and energy metabolism.


Assuntos
Lipidômica , Síndrome de Sjogren/sangue , Biomarcadores/sangue , Carnitina/análogos & derivados , Carnitina/sangue , Estudos de Casos e Controles , Cromatografia Líquida de Alta Pressão , Análise Discriminante , Feminino , Humanos , Masculino , Espectrometria de Massas , Fosfatidilcolinas/sangue , Sensibilidade e Especificidade , Triglicerídeos/sangue
9.
J Proteome Res ; 19(2): 864-872, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-31917576

RESUMO

Ankylosing spondylitis (AS) is a systemic, chronic, and inflammatory rheumatic disease that affects 0.2% of the population. Current diagnostic criteria for disease activity rely on subjective Bath Ankylosing Spondylitis Disease Activity Index scores. Here, we aimed to discover a panel of serum protein biomarkers. First, tandem mass tag (TMT)-based quantitative proteomics was applied to identify differential proteins between 15 pooled active AS and 60 pooled healthy subjects. Second, cohort 1 of 328 humans, including 138 active AS and 190 healthy subjects from two independent centers, was used for biomarker discovery and validation. Finally, biomarker panels were applied to differentiate among active AS, stable AS, and healthy subjects from cohort 2, which enrolled 28 patients with stable AS, 26 with active AS, and 28 healthy subjects. From the proteomics study, a total of 762 proteins were identified and 46 proteins were up-regulated and 59 proteins were down-regulated in active AS patients compared to those in healthy persons. Among them, C-reactive protein (CRP), complement factor H-related protein 3 (CFHR3), α-1-acid glycoprotein 2 (ORM2), serum amyloid A1 (SAA1), fibrinogen γ (FG-γ), and fibrinogen ß (FG-ß) were the most significantly up-regulated inflammation-related proteins and S100A8, fatty acid-binding protein 5 (FABP5), and thrombospondin 1 (THBS1) were the most significantly down-regulated inflammation-related proteins. From the cohort 1 study, the best panel for the diagnosis of active AS vs healthy subjects is the combination of CRP and SAA1. The area under the receiver operating characteristic (ROC) curve was nearly 0.900, the sensitivity was 0.970%, and the specificity was 0.805% at a 95% confidence interval from 0.811 to 0.977. Using 0.387 as the cutoff value, the predictive values reached 92.00% in the internal validation set (62 with active AS vs 114 healthy subjects) and 97.50% in the external validation phase (40 with active AS vs 40 healthy subjects). From the cohort 2 study, a panel of CRP and SAA1 can differentiate well among active AS, stable AS, and healthy subjects. For active AS vs stable AS, the area under the ROC curve was 0.951, the sensitivity was 96.43%, the specificity was 88.46% at a 95% confidence interval from 0.891 to 1, and the coincidence rate was 92.30%. For stable AS vs healthy humans, the area under the ROC curve was 0.908, the sensitivity was 89.29%, the specificity was 78.57% at a 95% confidence interval from 0.836 to 0.980, and the coincidence rate was 83.93%. For active AS vs healthy subjects, the predictive value was 94.44%. The results indicated that the CRP and SAA1 combination can potentially diagnose disease status, especially for active or stable AS, which will be conducive to treatment recommendation for patients with AS.


Assuntos
Espondilite Anquilosante , Biomarcadores , Proteína C-Reativa , Proteínas de Ligação a Ácido Graxo , Humanos , Proteômica , Curva ROC , Espondilite Anquilosante/diagnóstico , Trombospondina 1
10.
Int Immunopharmacol ; 75: 105768, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31382166

RESUMO

Ulcerative colitis (UC) is a major inflammatory bowel disease (IBD) which has become a global public health problem. Limonin is a triterpenoid extracted from citrus which possesses the capacities to against inflammations and cell apoptosis. However, the efficacy and the underlying mechanisms of limonin in the treatment of UC remain unclear. In this study, we first investigated the therapeutic effects of limonin on dextran sodiumsulfate (DSS)-induced UC in vivo by examining the changes of disease activity index (DAI), the colon length, the colon histology, and cyto/chemokine levels. We found that limonin markedly reduced DAI, intestinal damages, and the levels of pro-inflammatory cytokines, such as TNF-α and IL-6. In vitro, limonin significantly repressed the productions of pro-inflammatory cytokines in cultured normal colonic epithelial cells. Mechanistically, we demonstrated that limonin improved the prognosis of UC mainly through downregulating p-STAT3/miR-214 levels. Collectively, our results suggested that limonin was a novel therapeutic agent and it was expected to be translated into the clinic to improve the prognosis of UC.


Assuntos
Anti-Inflamatórios/uso terapêutico , Colite Ulcerativa/tratamento farmacológico , Limoninas/uso terapêutico , MicroRNAs/imunologia , Fator de Transcrição STAT3/imunologia , Animais , Anti-Inflamatórios/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/imunologia , Colite Ulcerativa/patologia , Colo/efeitos dos fármacos , Colo/imunologia , Colo/patologia , Sulfato de Dextrana , Células Epiteliais/efeitos dos fármacos , Interleucina-10/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Limoninas/farmacologia , Masculino , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Fator de Transcrição STAT3/genética , Transdução de Sinais/efeitos dos fármacos
11.
Talanta ; 107: 195-202, 2013 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-23598212

RESUMO

Mono-dispersed 3,4,9,10-perylene tetracarboxylic acid (PTCA) functionalized graphene sheets (PTCA-graphene) were fabricated by a chemical route and dispersed well in aqueous solution. PTCA-graphene with plenty of -COOH groups as electrostatic absorbing sites were beneficial to the loading of Cytochrome c (Cyt c). Cyt c, which was tightly immobilized on the PTCA-graphene modified glassy carbon electrode, maintained its natural conformation. Direct electron transfer of Cyt c and the electro-catalytic activity towards the reduction of H2O2 were also achieved. It has been substantiated that PTCA-graphene is a preferable biocompatible matrix for Cyt c.


Assuntos
Citocromos c/química , Enzimas Imobilizadas/química , Grafite/química , Perileno/análogos & derivados , Animais , Citocromos c/metabolismo , Técnicas Eletroquímicas , Transporte de Elétrons , Enzimas Imobilizadas/metabolismo , Cavalos , Peróxido de Hidrogênio/metabolismo , Oxirredução , Perileno/química
12.
Nanoscale ; 5(5): 1910-6, 2013 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-23354435

RESUMO

Zero bandgap and water soluble sulfonated graphene (SGE) has been introduced into an n-type semiconductor photocatalytic system to fabricate a Ag@AgBr/SGE composite photocatalyst. Due to its unique conduction and valence band dispersion and low Fermi level, SGE serves as an electron reservoir within the photocatalyst which enhances the charge carrier transfer and separation significantly. Furthermore, the stability and adsorptivity of Ag@AgBr/SGE are also improved owing to the sulfonic acid groups and conjugated sp(2) carbon network of SGE. The photocatalytic activity was found to be 11-fold higher than SGE-free Ag@AgBr upon the photodegradation of MO under visible light irradiation. This work provides a novel and in-depth perspective for understanding the graphene-involved photocatalytic mechanism and would stimulate the development of graphene-involved photocatalysts for the exploitation and utilization of solar energy.


Assuntos
Grafite/química , Luz , Ácidos Sulfônicos/química , Compostos Azo/química , Brometos/química , Catálise , Fotólise , Prata/química , Compostos de Prata/química
13.
Biosens Bioelectron ; 38(1): 402-6, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22727516

RESUMO

An enzymeless glucose biosensor based on polypyrrole nanofibers-supporting Au nanoparticles (Au/PPyNFs) was investigated in this study. The Au/PPyNFs heterogeneous composite materials were synthesized in-situ via hydrogen bonding interactions for the assembly of polyethyleneimine (PEI) on the surface of polypyrrole nanofibers (PPyNFs). By changing the molar ratio of PPy to HAuCl(4), Au/PPyNFs with different Au loadings were obtained. The morphology and composition of Au/PPyNFs were characterized using SEM, TEM, FTIR, XRD and XPS, respectively. The hybrids exhibited a high electrocatalytic activity toward glucose oxidation, which is prerequisite for the catalysts to be applied in amperometric glucose sensors. By using the nonenzymatic glucose sensor based on Au/PPyNFs, 0.2-13 mM glucose can be detected with a sensitivity of 1.003 µA cm(-2)mM(-1) and a good linearity (R(2)=0.9993) between current density and glucose concentration. The proposed glucose sensor provides a promising strategy to construct fast, sensitive, and anti-interfering amperometric sensors for early diagnosis and prevention of diabetes.


Assuntos
Técnicas Biossensoriais/métodos , Glucose/análise , Ouro/química , Nanofibras/química , Nanopartículas/química , Polímeros/química , Pirróis/química , Técnicas Eletroquímicas/métodos , Nanofibras/ultraestrutura , Nanopartículas/ultraestrutura , Oxirredução , Sensibilidade e Especificidade
14.
Biosens Bioelectron ; 26(2): 903-7, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20674330

RESUMO

An enzymeless biosensor based on CuxO/Cu electrode was investigated in this study. The XRD analysis confirmed that CuxO nanostructured material was composed of Cu2O and CuO. The FESEM images showed that the catalysts were flower-like with large surface area. From cyclic voltammograms, the peak current of CuxO/Cu electrode was 6, 6.3 and 1.7 times higher than that of the Cu foil, Cu2O/GCE and CuO/GCE electrodes, respectively. The biosensor based on CuxO/Cu exhibited excellent performance for glucose detection, giving a linear dependence between current and glucose concentration (R=0.996), with a low detection limit (0.049 mM) and high sensitivity (1.62 mA cm(-2) mM(-1)). Finally, the CuxO/Cu sensor was applied and checked in the glucose determination in blood serum samples.


Assuntos
Técnicas Biossensoriais/instrumentação , Glicemia/análise , Condutometria/instrumentação , Cobre/química , Eletrodos , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Sensibilidade e Especificidade
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