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1.
Int Immunopharmacol ; 101(Pt B): 108216, 2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34634689

RESUMO

Herpes zoster (HZ) is a recurrent nerve tissue infection caused by the reactivation of varicella-zoster virus (VZV). At present, two vaccines, the live attenuated vaccine Zostavax™ and AS01B-adjuvanted recombinant subunit vaccine Shingrix™, are commercially available for HZ. The latter is superior to the former in terms of efficacy and duration of immunity in the elderly. In this study, we used glycoprotein E (gE) as an antigen, and investigated the effects of various adjuvants (MF59, MF59/CpG 2006, and MF59/QS-21) on the immune response of C57BL/6J mice to find an alternative adjuvant to AS01B-like adjuvant of liposome/QS-21/MPL. In addition to safety, the gE-specific antibody, IgG antibody subtype, and cytokine secretion by splenocytes, and cell-mediated immune responses were determined using ELISA and ELISPOT assays, respectively. Our results showed no significant effects on the body weight, temperature, or behavior of mice vaccinated with PBS or all adjuvanted vaccines. All adjuvanted vaccine groups showed significantly higher gE-specific IgG antibody levels than the gE-alone group on day 28 after the first vaccine dose. In addition, all adjuvants induced a remarkable increase in both IgG1 and IgG2b levels. However, MF59/QS-21 and MF59/CpG 2006 showed comparable capacities to those of liposome/QS-21/MPL in increasing the IgG2c levels, being superior to MF59. Further investigation revealed that MF59 only induced a limited increase in the levels of Th1 and Th2 cytokines, while MF59/QS-21, MF59/CpG 2006, and liposome/QS-21/MPL led to a significant increase in the secretion of interferon gamma (IFN-γ), IL-2, IL-4, and IL-10 and showed a Th1-biased immune response. Moreover, MF59/QS-21, MF59/CpG 2006, and liposome/QS-21/MPL adjuvanted vaccines resulted in comparable gE-specific IFN-γ + immune cell responses. These results suggest that the combination of MF59 with QS-21 or CpG 2006 may be a promising adjuvant candidate for subunit HZ vaccines. Further investigations are needed to illustrate their durability and efficacy in aged mice.

2.
J Food Prot ; 84(12): 2116-2122, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34347862

RESUMO

ABSTRACT: In the present study, a risk assessment of pesticides, phthalates, and heavy metals in strawberries (n = 335) in recent years was conducted by determining the estimated daily intake, target hazard quotient, and hazard index. The study used 128 pesticides, 18 phthalates, and three heavy metals in this determination. It detected 51 pesticide residues in the strawberry samples, and 97.91% samples had levels of at least 1 of the 51 pesticides above the limit of detection. In addition, 2.39% of samples had pesticides higher than the Chinese maximum residue limit. Multiple pesticide residues were detected in most samples. Bis-2-ethylhexyl phthalate, diisobutyl phthalate, and dibutyl phthalate were detected in the strawberry samples, with a high frequency of detection. Their detectable rates were 100, 100, and 89.9%, respectively. In most samples, lead, cadmium, and nickel were detected, with detectable rates 75.76, 92.93, and 92.93%, respectively. The estimated daily intake of analyzed pesticide, phthalate, and heavy metal residues appears to be relatively low compared with the acceptable daily intake. The average target hazard quotients and hazard indices were less than 1. That means that customers who are exposed to the average contaminant levels may not pose a significant health risk. Our results show that the strawberries may be polluted by many kinds of contaminants. Therefore, monitoring of pesticide, phthalate, and heavy metal residues in strawberries should be increasingly developed to fully protect the health of the consumer.

3.
Biosens Bioelectron ; 185: 113251, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33905965

RESUMO

A novel photoelectrochemical immunosensor was constructed to monitor carcinoembryonic antigen (CEA) based on hybridization chain reaction (HCR)-mediated in situ generation of copper nanoparticles (Cu NPs) and subsequent Cu2+-dependent quenching reaction, in which titanium dioxide nanoparticles-sensitized double-shell zinc cadmium sulfide hollow nanospheres (TiO2/DS-ZnCdS)-modified ITO electrode and anti-CEA antibody-modified 96-well plate served as biological recognition and signal detection platforms, respectively. The synergistic effect of TiO2 NPs and DS-ZnCdS hollow nanospheres contributed to the improvement of photoelectric conversion efficiency, and HCR-mediated signal cascade benefited the enhancement of detection sensitivity. In the presence of CEA, biotin-labelled anti-CEA antibodies were immobilized onto anti-CEA antibody-modified 96-well plate, and triggered HCR process to form long double stranded DNA, which could adsorb a large number of Cu2+ ions and then in situ form Cu NPs on double stranded DNA template by a facile reduction reaction. After acid treatment, the dissolved Cu2+ ions could significantly reduce the photocurrent response due to the generation of CuxS. Under optimal conditions, the immunosensor exhibited a desirable liner range of 1 pg mL-1 - 50 ng mL-1 and a low detection limit of 0.1 pg mL-1, as well as excellent selectivity and stability. Meanwhile, the recoveries of human serum sample analysis ranged from 96.8% to 103.6%, and the relative standard deviation was less than 7.40%, showing a good feasibility in early clinical diagnosis.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Nanosferas , Antígeno Carcinoembrionário , Técnicas Eletroquímicas , Humanos , Imunoensaio , Limite de Detecção , Titânio
4.
J Infect Dev Ctries ; 14(8): 908-917, 2020 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-32903236

RESUMO

INTRODUCTION: Hypocalcemia has been widely recognized in sepsis patients. However, the cause of hypocalcemia in sepsis is still not clear, and little is known about the subcellular distribution of Ca2+ in tissues during sepsis. METHODOLOGY: We measured the dynamic change in Ca2+ levels in body fluid and subcellular compartments, including the cytosol, endoplasmic reticulum and mitochondria, in major organs of cecal ligation and puncture (CLP)-operated rats, as well as the subcellular Ca2+ flux in HUVECs which treated by endotoxin and cytokines. RESULTS: In the model of CLP-induced sepsis, the blood and urinary Ca2+ concentrations decreased rapidly, while the Ca2+ concentration in ascites fluid increased. The Ca2+ concentrations in the cytosol, ER, and mitochondria were elevated nearly synchronously in major organs in our sepsis model. Moreover, the calcium overload in CLP-operated rats treated with calcium supplementation was more severe than that in the non-calcium-supplemented rats but was alleviated by treatment with the calcium channel blocker verapamil. Similar subcellular Ca2+ flux was found in vitro in HUVECs and was triggered by lipopolysaccharide (LPS)/TNF-α. CONCLUSIONS: Ca2+ influx from the blood into the intercellular space and Ca2+ release into ascites fluid may cause hypocalcemia in sepsis and that this process may be due to the synergistic effect of endotoxin and cytokines.


Assuntos
Cálcio/sangue , Hipocalcemia/etiologia , Sepse/fisiopatologia , Animais , Cálcio/urina , Modelos Animais de Doenças , Humanos , Hipocalcemia/sangue , Hipocalcemia/urina , Lipopolissacarídeos , Ratos , Ratos Sprague-Dawley , Sepse/sangue , Sepse/urina , Fator de Necrose Tumoral alfa
5.
Biosens Bioelectron ; 142: 111557, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31400727

RESUMO

Nowadays, acquired immunodeficiency syndrome has become a formidable danger to human health, and its early diagnosis is urgent need with the increasing quantity of patients around the world. Herein, we first synthesized beta-cyclodextrin-functionalized CdS nanorods (ß-CD@CdS NRs) with high stability and desirable photo-electricity activity, and served as easy-to-assemble building modules to design a novel photoelectrochemical biosensor for human immune deficiency virus (HIV) DNA detection by coupling with catalytic hairpin assembly (CHA)-mediated biocatalytic precipitation and the host-guest interaction between adamantine (ADA) and ß-CD. In the presence of HIV DNA, CHA process was triggered with the aid of hairpin DNA1 and ADA-labelled hairpin DNA2, and then generated large amounts of G-quadruplex, which could be formed hemin/G-quadruplex DNAzyme to catalyze 4-chloro-1-naphthol to generate insoluble precipitation on photoelectrode surface, followed by the decreased photocurrent response due to the corresponding stereo-hindrance effect. Under optimized conditions, this biosensor exhibited wide linear dynamic range (10 fM - 1 nM) and low detection limit of 1.16 fM, as well as high sensitivity, excellent stability, and satisfactory feasibility in human-serum samples. Moreover, the prepared ß-CD@CdS NRs could be applied to the construction of other advanced sensing platform, showing great prospect in clinical diagnostics.


Assuntos
Compostos de Cádmio/química , DNA Viral/sangue , Infecções por HIV/sangue , HIV/isolamento & purificação , Nanotubos/química , Sulfetos/química , beta-Ciclodextrinas/química , Técnicas Biossensoriais/métodos , DNA Catalítico/química , DNA Viral/análise , Técnicas Eletroquímicas/métodos , Quadruplex G , Infecções por HIV/diagnóstico , Humanos , Limite de Detecção , Nanotubos/ultraestrutura
6.
Analyst ; 144(15): 4661-4666, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31259991

RESUMO

A split-type photoelectrochemical immunosensor was designed for the ultrasensitive monitoring of prostate-specific antigen (PSA) based on a Cu2+-mediated catalytic reaction for inhibiting the in situ generation of CdS quantum dots (QDs) coupled with the enhancement of the CdS/MoS2 heterojunction; it was constructed by the stepwise modification of MoS2 QDs and CdS QDs onto an ITO electrode surface. In the presence of PSA, CuO NP-labeled anti-PSA antibodies were immobilized onto an anti-PSA antibody-modified 96-well plate via a sandwich immunoreaction and dissolution by hydrochloric acid to obtain a large number of Cu2+ ions. As the Cu2+-triggered catalytic oxidization of glutathione occurred, the in situ growth of CdS QDs as a signal indicator was significantly suppressed, resulting in reduction in the photocurrent response. Under optimal conditions, the biosensor exhibited desirable linearity in the range from 0.5 pg mL-1 to 10 ng mL-1, low detection limit of 0.29 pg mL-1, satisfactory selectivity, and good stability. It was applied to PSA detection in human serum, suggesting a great potential for early diagnostics of some cancers.


Assuntos
Cobre/química , Antígeno Prostático Específico/sangue , Pontos Quânticos/química , Anticorpos Imobilizados/imunologia , Técnicas Biossensoriais/métodos , Compostos de Cádmio/química , Compostos de Cádmio/efeitos da radiação , Dissulfetos/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Glutationa/química , Humanos , Imunoensaio/métodos , Luz , Limite de Detecção , Masculino , Molibdênio/química , Oxirredução , Processos Fotoquímicos , Antígeno Prostático Específico/imunologia , Pontos Quânticos/efeitos da radiação , Sulfetos/química , Sulfetos/efeitos da radiação , Compostos de Estanho/química
7.
Front Microbiol ; 10: 1185, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178855

RESUMO

The class Thermoleophilia is one of the deep-rooting lineages within the Actinobacteria phylum and metagenomic investigation of microbial diversity suggested that species associated with the class Thermoleophilia are abundant in hot spring and soil samples. However, very few species of this class have been cultivated and characterized. Our understanding of the phylogeny and taxonomy of Thermoleophilia is solely based on 16S rRNA sequence analysis of limited cultivable representatives, but no other phenotypic or genotypic characteristics are known that can clearly discriminate members of this class from the other taxonomic units within the kingdom bacteria. This study reports phylogenomic analysis for 12 sequenced members of this class and clearly resolves the interrelationship of not yet cultivated species with reconstructed genomes and known type species. Comparative genome analysis discovered 12 CSIs in different proteins and 32 CSPs that are specific to all species of this class. In addition, a large number of CSIs or CSPs were identified to be unique to certain lineages within this class. This study represents the first and most comprehensive phylogenetic analysis of the class Thermoleophilia, and the identified CSIs and CSPs provide valuable molecular markers for the identification and delineation of species belonging to this class or its subordinate taxa.

8.
Chem Commun (Camb) ; 54(84): 11861-11864, 2018 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-30221277

RESUMO

The chemiluminescence (CL) of CdTe quantum dots (QDs) in the presence of peroxyoxalate and hydrogen peroxide was explored and applied for sensitive immunoassay, in which the amplified CL originated from the resonance energy transfer and annihilation of hole-injected and electron-injected QDs.


Assuntos
Elétrons , Imunoensaio/métodos , Pontos Quânticos/química , Compostos de Cádmio/química , Transferência de Energia , Luminescência , Telúrio/química , alfa-Fetoproteínas/química
9.
Analyst ; 143(12): 2895-2900, 2018 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-29808182

RESUMO

Based on enzymatic biocatalytic precipitation to quench the amplified photocurrent response generated from WS2 nanosheets-sensitized CdS quantum dots heterostructure, a novel photoelectrochemical immunosensor was constructed for sensitive alpha-fetoprotein (AFP) monitoring. The immunosensor comprised an anti-AFP antibody and a horseradish peroxidase-tagged anti-AFP antibody (HRP-Ab2), which served as a capture unit and a signal indicator, respectively. In the presence of AFP, HRP-Ab2 was immobilized on the electrode surface for establishing a sandwich-type immunocomplex via antigen-antibody interaction, and subsequently catalyzed 4-chloro-1-naphthol to form the nonconductive and insoluble precipitate. This precipitation effectively impeded the diffusion and electron transfer of the electron donor, thus achieving decreased photocurrent. Under optimized conditions, excellent linearity range (1 pg mL-1-20 ng mL-1), satisfactory detection limit (0.43 pg mL-1), desirable selectivity and good stability were obtained for the as-designed immunosensor. Moreover, the application of AFP determination in human serum allowed the immunosensor to hold great potential for early diagnostics of some cancer diseases.


Assuntos
Técnicas Biossensoriais , Compostos de Cádmio/química , Imunoensaio , Pontos Quânticos , Compostos de Tungstênio/química , alfa-Fetoproteínas/análise , Técnicas Eletroquímicas , Humanos , Limite de Detecção , Nanoestruturas
10.
Chemistry ; 24(53): 14010-14027, 2018 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-29687506

RESUMO

Photoelectrochemical (PEC) analysis is a new detection technique developed in recent years, which has the advantages of high sensitivity, low background signal and desirable selectivity, obtaining the great progress in sensing applications. Semiconductor nanomaterials with excellent photoelectric activity have played a vital role in the construction of PEC sensing platform. Thus, this Review introduces the recent advances of semiconductor nanomaterials-based PEC analysis, and describes the typical PEC sensing strategies. Some representative nanomaterials, including metallic oxides, metallic sulfides, graphitic carbon nitride, transition-metal dichalcogenides and quantum dots, are summarized for advanced PEC devices, as well as their applications in nucleic acid analysis, immunoassays, cell detection, protein and enzyme sensing, and small biomolecule monitoring. Finally, some future opportunities and challenges of PEC biosensing are also discussed.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas , Nanoestruturas/química , Semicondutores , Biomarcadores/análise , Grafite/química , Humanos , Metais/química , Ácidos Nucleicos/análise , Proteínas/análise
11.
Proc Biol Sci ; 284(1869)2017 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-29237851

RESUMO

Arthropods comprise the majority of all described animal species, and understanding their evolution is a central question in biology. Their developmental processes are under the precise control of distinct hormonal regulators, including the sesquiterpenoids juvenile hormone (JH) and methyl farnesoate. The control of the synthesis and mode of action of these hormones played important roles in the evolution of arthropods and their adaptation to diverse habitats. However, the precise roles of non-coding RNAs, such as microRNAs (miRNAs), controlling arthropod hormonal pathways are unknown. Here, we investigated the miRNA regulation of the expression of the juvenile hormone acid methyltransferase gene (JHAMT), which encodes a rate-determining sesquiterpenoid biosynthetic enzyme. Loss of function of the miRNA bantam in the fly Drosophila melanogaster increased JHAMT expression, while overexpression of the bantam repressed JHAMT expression and resulted in pupal lethality. The male genital organs of the pupae were malformed, and exogenous sesquiterpenoid application partially rescued the genital deformities. The role of the bantam in the regulation of sesquiterpenoid biosynthesis was validated by transcriptomic, qPCR and hormone titre (JHB3 and JH III) analyses. In addition, we found a conserved set of miRNAs that interacted with JHAMT, and the sesquiterpenoid receptor methoprene-tolerant (Met) in different arthropod lineages, including insects (fly, mosquito and beetle), crustaceans (water flea and shrimp), myriapod (centipede) and chelicerate (horseshoe crab). This suggests that these miRNAs might have conserved roles in the post-transcriptional regulation of genes in sesquiterpenoid pathways across the Panarthropoda. Some of the identified lineage-specific miRNAs are potential targets for the development of new strategies in aquaculture and agricultural pest control.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Metiltransferases/genética , Transdução de Sinais/genética , Animais , Artrópodes/genética , Artrópodes/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Metiltransferases/metabolismo , MicroRNAs
12.
Biosens Bioelectron ; 96: 8-16, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28454070

RESUMO

Photoelectrochemical (PEC) biosensing is a popular research hotspot that has attracted substantial attention from chemists and biologists due to its low cost and desirable sensitivity. The PEC biosensing mainly refers to the influence of the interaction between recognition element and analyte on photocurrent signal, which involves the charge and energy transfer of PEC reaction between electron donor/acceptor and photoactive material upon light irradiation. Understanding the fundamentals of PEC strategy benefits the development of next-generation PEC sensors. However, the research on detection mechanism of PEC sensors is in the initial stage and need to be further exploited. Thus, with a particular focus on the signal transduction formats, this review highlights the novel concept on PEC sensing strategies, and categorizes the recent illustrative examples into three signaling principles: reactant determinant, electron transfer and energy transfer, providing the comprehensive design guidelines for researchers to develop more advanced PEC sensors. The prospects and challenges for future work are also included.


Assuntos
Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Nanoestruturas/química , DNA/análise , Transporte de Elétrons , Transferência de Energia , Fluorometria/métodos , Oxirredução , Propriedades de Superfície
13.
Pest Manag Sci ; 73(9): 1944-1952, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28247468

RESUMO

BACKGROUND: In a previous study we have demonstrated that insect 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) can be a potential selective insecticide target. Three series of inhibitors were designed on the basis of the difference in HMGR structures from Homo sapiens and Manduca sexta, with the aim of discovering potent selective insecticide candidates. RESULTS: An in vitro bioassay showed that gem-difluoromethylenated statin analogues have potent effects on JH biosynthesis of M. sexta and high selectivity between H. sapiens and M. sexta. All series II compounds {1,3,5-trisubstituted [4-tert-butyl 2-(5,5-difluoro-2,2-dimethyl-6-vinyl-4-yl) acetate] pyrazoles} have some effect on JH biosynthesis, whereas most of them are inactive on human HMGR. In particular, the IC50 value of compound II-12 (37.8 nm) is lower than that of lovastatin (99.5 nm) and similar to that of rosuvastatin (24.2 nm). An in vivo bioassay showed that I-1, I-2, I-3 and II-12 are potential selective insecticides, especially for lepidopteran pest control. A predictable and statistically meaningful CoMFA model of 23 inhibitors (20 as training sets and three as test sets) was obtained with a value of q2 and r2 of 0.66 and 0.996 respectively. The final model suggested that a potent insect HMGR inhibitor should contain suitable small and non-electronegative groups in the ring part, and electronegative groups in the side chain. CONCLUSION: Four analogues were discovered as potent selective lepidopteran HMGR inhibitors, which can specifically be used for lepidopteran pest control. The CoMFA model will be useful for the design of new selective insect HMGR inhibitors that are structurally related to the training set compounds. © 2017 Society of Chemical Industry.


Assuntos
Hidroximetilglutaril-CoA Redutases/metabolismo , Inibidores de Hidroximetilglutaril-CoA Redutases/química , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Inseticidas/química , Inseticidas/farmacologia , Lepidópteros/enzimologia , Relação Quantitativa Estrutura-Atividade , Animais , Desenho de Fármacos , Humanos , Hidroximetilglutaril-CoA Redutases/química , Modelos Moleculares , Conformação Proteica
14.
Chem Sci ; 7(1): 774-780, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-28966769

RESUMO

In this work, a wavelength-resolved ratiometric photoelectrochemical (WR-PEC) technique was investigated and employed to construct a new type of PEC sensor with good sensitivity and anti-interference ability. The WR-PEC hybrid photoelectrodes were stepwise assembled using semiconductor quantum dots (QDs) and photoactive dyes. Under continuous irradiation, the photocurrent-wavelength (I-λ) curves reveal the dependence of the photocurrent on the wavelength. By monitoring the ratios of the two different PEC peak values, a wavelength-resolved ratiometric strategy was realized. Using CdS QDs and methylene blue (MB) as photoactive models, a dual-anodic WR-PEC sensor was established for sensitive detection of Cu2+. This ratiometric strategy was identified to be based on the quenching effect of Cu2+ towards CdS QDs and enhancement of the MB photocurrent through catalytic oxidation of leuco-MB. Under continuous illumination from 400 nm to 800 nm at a 0.1 V bias potential, a WR-PEC sensor for Cu2+ was developed with a wide linear range and a detection limit of 0.37 nM. This WR-PEC had a greatly improved anti-interference ability in a complex environment, and showed acceptable stability. Moreover, using the CdS/magnesium phthalocyanine (MgPc) and CdTe/MgPc as photoelectrodes, anodic-cathodic and dual-cathodic WR-PEC sensors were established, respectively. The WR-PEC technique could serve as a novel concept for designing ratiometric or multi-channel PEC sensors.

15.
Biosens Bioelectron ; 77: 557-64, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26476013

RESUMO

This work developed a CdS/MoS2 heterojunction-based photoelectrochemical biosensor for sensitive detection of DNA under the enhanced chemiluminescence excitation of luminol catalyzed by hemin-DNA complex. The CdS/MoS2 photocathode was prepared by the stepwise assembly of MoS2 and CdS quantum dots (QDs) on indium tin oxide (ITO), and achieved about 280% increasing of photocurrent compared to pure CdS QDs electrode due to the formation of heterostructure. High photoconversion efficiency in the photoelectrochemical system was identified to be the rapid spatial charge separation of electron-hole pairs by the extension of electron transport time and electron lifetime. In the presence of target DNA, the catalytic hairpin assembly was triggered, and simultaneously the dual hemin-labeled DNA probe was introduced to capture DNA/CdS/MoS2 modified ITO electrode. Thus the chemiluminescence emission of luminol was enhanced via hemin-induced mimetic catalysis, leading to the physical light-free photoelectrochemical strategy. Under optimized conditions, the resulting photoelectrode was proportional to the logarithm of target DNA concentration in the range from 1 fM to 100 pM with a detection limit of 0.39 fM. Moreover, the cascade amplification biosensor demonstrated high selectivity, desirable stability and good reproducibility, showing great prospect in molecular diagnosis and bioanalysis.


Assuntos
DNA/análise , DNA/genética , Medições Luminescentes/instrumentação , Molibdênio/química , Semicondutores , Análise de Sequência de DNA/instrumentação , Técnicas Biossensoriais/instrumentação , Compostos de Cádmio/química , Condutometria/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Dispositivos Ópticos , Óxidos/química , Fotoquímica/instrumentação , Reprodutibilidade dos Testes , Compostos de Selênio/química , Sensibilidade e Especificidade , Análise de Sequência de DNA/métodos
16.
Vaccine ; 33(32): 3859-64, 2015 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-26126669

RESUMO

Despite significant efforts directed toward research on HIV-1 vaccines, a truly effective immunogen has not been achieved. However, the broadly neutralizing antibodies (BnAbs) 2F5 and 4E10, targeting the highly conserved membrane proximal external region (MPER) of HIV-1, are two promising tools for vaccine development. Here we engrafted the MPER into the linker domain between the trimeric core structure and the transmembrane domain of influenza A virus HA2 to investigate the potential of such chimeric viruses to elicit HIV-1 neutralizing antibodies. In the context of proliferating attenuated influenza A viruses, these HIV-1 neutralizing antibody epitopes could be continuously expressed and mimicked their native conformation to induce humoral immune responses. While MPER-specific antibodies could be detected in serum of guinea pigs vaccinated with the chimeric viruses, they exhibited only weakly neutralizing activities. These antisera from vaccinated animals neutralized viruses of clades B and BC (tier 1), but not of clades AE (tier 1) and C (tier 2). These results suggest that influenza A virus can be used as a vehicle for displaying MPER and inducing BnAbs, but it provides limited protection against HIV-1 infection. In the future development of HIV-1 vaccines by rational design, a more effective live virus vector or multiple antigens should be chosen to facilitate the process of neutralizing antibody maturation.


Assuntos
Vacinas contra a AIDS/genética , Vacinas contra a AIDS/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Anti-HIV/sangue , HIV-1/imunologia , Vacinas contra Influenza/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Animais , Reações Cruzadas , Feminino , Cobaias , HIV-1/genética , Testes de Neutralização , Vacinas Atenuadas/genética , Vacinas Atenuadas/imunologia , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética
17.
Anal Chem ; 87(10): 5430-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25902380

RESUMO

A catalytic hairpin assembly (CHA)-programmed porphyrin-DNA complex was designed to trigger the chemiluminescence as photoelectrochemical initiator for DNA sensing. First, the programmed double strand DNA (dsDNA) was formed using two hairpin DNAs as assembly components via target-assisted CHA reaction, and then immobilized on a capture DNA/CdS quantum dots modified electrode. The porphyrin (FeTMPyP) was conveniently assembled on a dsDNA scaffold via the groove interaction. The FeTMPyP@dsDNA complex possessed high catalytic activity toward luminol oxidation to generate the desirable chemiluminescence with high stability under various temperature and alkaline conditions. By integrating the signal amplification capacity of CHA and in situ FeTMPyP-mediated chemiluminescence as excitation light, an amplified photoelectrochemical sensing strategy is proposed for DNA detection. Under optimized conditions, the biosensor shows a wide linear range from 5 to 10000 fM with a detection limit of 2.2 fM. Moreover, the developed photoelectrochemical device exhibits excellent selectivity, high stability, and acceptable fabrication reproducibility. The CHA-programmed porphyrin-DNA strategy not only extends the applications of photoelectrochemistry, but also presents a novel methodology in bioanalysis.


Assuntos
Técnicas Biossensoriais/métodos , DNA/análise , DNA/química , Sequências Repetidas Invertidas , Luz , Metaloporfirinas/química , Sequência de Bases , Compostos de Cádmio/química , Catálise , DNA/genética , Eletroquímica , Concentração de Íons de Hidrogênio , Limite de Detecção , Medições Luminescentes , Modelos Moleculares , Conformação de Ácido Nucleico , Oxirredução , Pontos Quânticos/química , Sulfetos/química , Temperatura
18.
Hum Vaccin Immunother ; 10(12): 3642-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25483696

RESUMO

Traditionally, infectivity of a trivalent live attenuated influenza vaccines (LAIVs) is titrated by determining the 50% egg infectious dose assay (EID50) or plaque forming units (PFU), which requires specific monoclonal antibodies to neutralize 2 strains while estimating the titer of the non-neutralized strain. Compared to this time-consuming, laborious, subjective and variable process, reverse transcription-quantitative real-time PCR (RT-qPCR) technology has advantages of rapidity, sensitivity, reproducibility and reduced contamination, thus has been applied widely for detecting pathogens and measuring viral titers. In this study, the critical harvest time was determined to be 18 h post-infection (hpi) for type A influenza and 12 hpi for type B influenza, but no significant difference between titers at 12 hpi and 18 hpi for the type B strain was observed. In conclusion, trivalent LAIVs can be titrated simultaneously within 24 h by this one-step RT-qPCR assay, which yielded titers comparable to those obtained by the traditional EID50 assay. Therefore, the RT-qPCR assay may be used as a highly specific, sensitive, precise and rapid alternative to the EID50 assay for titering LAIVs.


Assuntos
Vacinas contra Influenza/normas , Orthomyxoviridae/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Humanos , Vacinas contra Influenza/análise , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Vacinas Atenuadas/normas
19.
Anal Chem ; 86(24): 12362-8, 2014 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-25393151

RESUMO

A novel photoelectrochemical sensing strategy is designed for DNA detection on the basis of in situ generation of an electron acceptor via the catalytic reaction of hemin toward H2O2. The photoelectrochemical platform was established by sequential assembly of near-infrared CdTe quantum dots, capture DNA, and a hemin-labeled DNA probe to form a triple-helix molecular beacon (THMB) structure on an indium tin oxide electrode. According to the highly catalytic capacity of hemin toward H2O2, a photoelectrochemical mechanism was then proposed, in which the electron acceptor of O2 was in situ-generated on the electrode surface, leading to the enhancement of the photocurrent response. The utilization of CdTe QDs can extend the absorption edge to the near-infrared band, resulting in an increase in the light-to-electricity efficiency. After introducing target DNA, the THMB structure is disassembled and releases hemin and, thus, quenches the photocurrent. Under optimized conditions, this biosensor shows high sensitivity with a linear range from 1 to 1000 pM and detection limit of 0.8 pM. Moreover, it exhibits good performance of excellent selectivity, high stability, and acceptable fabrication reproducibility. This present strategy opens an alternative avenue for photoelectrochemical signal transduction and expands the applications of hemin-based materials in photoelectrochemical biosensing and clinical diagnosis.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas/métodos , Elétrons , Hemina/química , Processos Fotoquímicos , Sequência de Bases , Catálise , Primers do DNA
20.
ACS Appl Mater Interfaces ; 6(18): 15991-7, 2014 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-25170538

RESUMO

A "signal-on" photoelectrochemical sensing strategy for selective determination of Pb(2+) is designed on the basis of the combination of Pb(2+)-induced conformational conversion, the amplified effect of reduced graphene oxide (RGO) and resonance energy transfer between CdS quantum dots (QDs) and gold nanoparticles (AuNPs). The RGO/CdS/aptamer platform is constructed via a stepwise modification method, and characterized by electrochemical impedance spectroscopy. In the absence of Pb(2+), the AuNP-labeled DNA, as a signal quenching element, can be introduced by hybridization with aptamer on the surface of sensing platform, which quenches the photocurrent of QDs via an energy transfer process. Upon addition of Pb(2+), the aptamer is induced into a G-quadruplex structure, which can greatly hinder the hybridization between aptamer and AuNP-labeled DNA due to the competitive occupation of binding sites and steric effect, leading to the recovery of photocurrent. Under optimized conditions, this "signal-on" photoelectrochemical biosensor shows a linear relationship between photocurrent variation and the logarithm of Pb(2+) concentration in the range of 0.1-50 nM with a detection limit of 0.05 nM. Meanwhile, it also exhibits good selectivity for Pb(2+) over other interfering ions, and is successfully applied to the detection of Pb(2+) in environmental water samples. By substituting the aptamers with other sequences, this proposed strategy could be conveniently extended to detect different targets as versatile photoelectrochemical devices.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Chumbo/análise , Pontos Quânticos/química , Técnicas Biossensoriais/instrumentação , Compostos de Cádmio/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Transferência Ressonante de Energia de Fluorescência/instrumentação , Transferência Ressonante de Energia de Fluorescência/métodos , Grafite/química , Sulfetos/química
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