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1.
Anal Chem ; 95(50): 18611-18618, 2023 12 19.
Artículo en Inglés | MEDLINE | ID: mdl-38057995

RESUMEN

Deoxynivalenol (DON) is a mycotoxin secreted by Fusarium species, posing great harm to food safety and human health. Therefore, it is of great significance to study its toxic effects and mechanism. miR-34a is a representative biomarker during the process of DON-induced apoptosis. Herein, a DON-triggered dual-color composite probe was constructed for simultaneous imaging of DON and miR-34a in living cells. The aptamer blocks the recognition sequence of miR-34a to realize DON-triggered cell imaging. The specific binding of DON with its aptamer and HCR induced by miR-34a resulted in the recovery of fluorescence of the dual-color Au NCs. Under the optimal conditions, the correlation between the relative fluorescence intensities of dual-color Au NCs showed good linear relationships with the logarithm of DON and miR-34a concentration, respectively. With the increase in DON concentration (0-20 µg/mL) and stimulation time (0-12 h), the fluorescence of dual-color Au NCs gradually recovered. This dual-color Au NCs composite probe can realize simultaneous detection of DON and miR-34a induced by DON, which is significant for verifying the cytotoxic mechanism of DON.


Asunto(s)
MicroARNs , Micotoxinas , Tricotecenos , Humanos , Oro , Tricotecenos/toxicidad , Micotoxinas/toxicidad , MicroARNs/genética , MicroARNs/metabolismo
2.
Crit Rev Food Sci Nutr ; : 1-20, 2023 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-36660935

RESUMEN

Food safety is a global issue in public hygiene. The accurate, sensitive, and on-site detection of various food contaminants performs significant implications. However, traditional methods suffer from the time-consuming and professional operation, restricting their on-site application. Hydrogels with the merits of highly porous structure, high biocompatibility, good shape-adaptability, and stimuli-responsiveness offer a promising biomaterial to design sensors for ensuring food safety. This review describes the emerging applications of hydrogel-based sensors in food safety inspection in recent years. In particular, this study elaborates on their fabrication strategies and unique sensing mechanisms depending on whether the hydrogel is stimuli-responsive or not. Stimuli-responsive hydrogels can be integrated with various functional ligands for sensitive and convenient detection via signal amplification and transduction; while non-stimuli-responsive hydrogels are mainly used as solid-state encapsulating carriers for signal probe, nanomaterial, or cell and as conductive media. In addition, their existing challenges, future perspectives, and application prospects are discussed. These practices greatly enrich the application scenarios and improve the detection performance of hydrogel-based sensors in food safety detection.

3.
Cancer Cell Int ; 22(1): 143, 2022 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-35366902

RESUMEN

BACKGROUND: Pancreatic adenocarcinoma (PAAD) is a severe malignant with a 5-year survival rate of approximately 9%. Oleanolic acid is a well-known natural triterpenoid which exhibits pharmacological activities. We previously synthesized a series of oleanolic acid derivatives and evaluated the tumor-suppressive activity of olean-28,13ß-lactam (B28) in prostate cancer. However, the detailed mechanism remains to be understood. METHODS: The anti-tumor activity of B28 in PAAD was confirmed by RTCA, colony formation assay and flow cytometry. GO and KEGG enrichment analyses were performed to analyze the differentially expressed genes (DEGs) obtained by RNA sequencing. The effects of B28 on cell bioenergetics were evaluated by seahorse analyzer. Lenti-virus packaged plasmids were performed to knockdown or overexpress target genes. Alteration of mitochondrial membrane potential, ROS and GSH/GSSG were measured by corresponding detection kits according to the manufacturer's protocol. RESULTS: We evaluated and confirmed the promising anti-tumor activity of B28 in vitro. RNA-seq profile indicated that multiple metabolic pathways were interrupted in B28 treated PAAD cells. Next, we demonstrated that B28 induces cellular bioenergetics crisis to inhibit PAAD cells growth and induce cell death. We further validated that cell cycle arrest, inhibition of cell growth, cell apoptosis and cell bioenergetics disruption were functionally rescued by ROS scavenger NAC. Mechanistically, we found glutamine metabolism was inhibited due to B28 administration. Moreover, we validated that down-regulation of GLS1 contributes to ROS generation and bioenergetics interruption induced by B28. Furthermore, we elucidated that YTHDF1-GLS1 axis is the potential downstream target of B28 to induce PAAD cell metabolic crisis and cell death. Finally, we also confirmed the anti-tumor activity of B28 in vivo. CONCLUSIONS: Current study demonstrates B28 disrupts YTDFH1-GLS1 axis to induce ROS-dependent cell bioenergetics crisis and cell death which finally suppress PAAD cell growth, indicating that this synthesized olean-28,13ß-lactam maybe a potent agent for PAAD intervention.

4.
J Immunol ; 205(2): 387-397, 2020 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-32554432

RESUMEN

Dendritic cells (DCs) are essential APCs and play a crucial role in initiating and regulating the adaptive immune response. In this study, we have reported that P2Y6, a member of G protein-coupled receptors, inhibits the maturation and activation of DCs via suppressing the activation of the transcription factor NF-κB. Furthermore, loss of P2Y6 does not impact T cells homeostasis in the steady-state. However, in vitro studies show that P2Y6 signaling inhibits the production of IL-12 and IL-23 and the polarization of Th1 and Th17 subsets mediated by DCs. In addition, we find that mice lacking P2Y6 develop more severe experimental autoimmune encephalomyelitis compared with wild-type mice. Our results indicate that P2Y6 functions as a pivotal regulator on DC maturation, and the loss of P2Y6 results in the aggravated experimental autoimmune encephalomyelitis, which suggests that P2Y6 may play a pivotal role in the pathogenesis of autoimmune diseases.


Asunto(s)
Células Dendríticas/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Esclerosis Múltiple/inmunología , Receptores Purinérgicos P2/metabolismo , Células TH1/inmunología , Células Th17/inmunología , Animales , Diferenciación Celular , Células Cultivadas , Modelos Animales de Enfermedad , Humanos , Interleucina-12/metabolismo , Interleucina-23/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores Purinérgicos P2/genética , Transducción de Señal
5.
J Biochem Mol Toxicol ; 36(11): e23192, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35929395

RESUMEN

To investigate the potential antitumor activity of synthetic triterpenoid, methyl-2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me) in pancreatic ductal adenocarcinoma (PDAC), MTT cytotoxicity assay, and xenograft nude mice assay were performed to evaluate tumor growth in vitro and in vivo. Seahorse XFe96 bioenergetics analyzer was applied to determine aerobic glycolysis and mitochondrial respiration. Western blot and quantitative reverse transcription-polymerase chain reactions are used to detect protein and messenger RNA transcripts of SLC1A5 and metabolic enzymes. We confirmed the strong antitumor activity of CDDO-Me in suppressing PDAC growth. Mechanistically, we demonstrated CDDO-Me induced mitochondrial respiration and aerobic glycolysis dysfunction. We also verified CDDO-Me downregulated glutamine transporter SLC1A5, resulting in excessive reactive oxygen species (ROS) levels that suppressed tumor growth. Moreover, we confirmed that SLC1A5 depletion reduced the ratio of glutathione/oxidized glutathione. We also found CDDO-Me could inhibit N-linked glycosylation of SLC1A5, which promotes protease-mediated degradation. Finally, we confirmed SLC1A5 was significantly overexpressed in PDAC and closely correlated with the poor prognosis of PDAC patients. Our work uncovers CDDO-Me is effective at suppressing PDAC cell growth in vitro and in vivo and illuminates CDDO-Me caused excessive ROS and cellular bioenergetics disruption which contributed to CDDO-Me inhibited PDAC growth. Our data highlights CDDO-Me could be considered a potential compound for PDAC therapy, and SLC1A5 could be a novel biomarker for PDAC patients.


Asunto(s)
Adenocarcinoma , Ácido Oleanólico , Neoplasias Pancreáticas , Triterpenos , Ratones , Animales , Humanos , Triterpenos/farmacología , Especies Reactivas de Oxígeno/metabolismo , Ratones Desnudos , Apoptosis , Ácido Oleanólico/farmacología , Neoplasias Pancreáticas/metabolismo , Línea Celular Tumoral , Metabolismo Energético , Antígenos de Histocompatibilidad Menor/metabolismo , Antígenos de Histocompatibilidad Menor/farmacología , Sistema de Transporte de Aminoácidos ASC/metabolismo , Neoplasias Pancreáticas
6.
Mikrochim Acta ; 189(8): 296, 2022 07 28.
Artículo en Inglés | MEDLINE | ID: mdl-35900604

RESUMEN

Aptamers against deoxynivalenol (DON) were selected through capture-systematic evolution of ligands by exponential enrichment. Through isothermal titration calorimetry and fluorimetric assay, aptamer candidate DN-2 demonstrated good affinity to DON with Kd value of 40.36 ± 6.32 nM. Accordingly, a Forster resonance energy transfer aptasensor was fabricated by using the aptamer DN-2 combined with AuCu bimetallic nanoclusters as energy donor and MoS2 nanosheets as energy acceptor. Under the optimal conditions, the fluorescence response was utilized for DON quantitative determination ranging from 5 to 100 ng/mL with a detection limit of 1.87 ng/mL. The practical application of this method was verified in maize flour samples and demonstrated a satisfied recovery of 94.6 ~ 103.1%. The obtained aptamers and their application in DON determination provide a new tool for DON monitoring in various foodstuff.


Asunto(s)
Aptámeros de Nucleótidos , Aptámeros de Nucleótidos/química , Transferencia Resonante de Energía de Fluorescencia/métodos , Fluorometría , Molibdeno/química , Tricotecenos
7.
Mikrochim Acta ; 190(1): 39, 2022 12 30.
Artículo en Inglés | MEDLINE | ID: mdl-36585487

RESUMEN

Zeolitic imidazolate framework (ZIF-8) base-aptamer "gate-lock" biomaterial probes have been synthesized for monitoring intracellular deoxynivalenol (DON) and cytochrome c (cyt c) levels. The aptamer and organic fluorescent dye were regarded as a recognition element and a sensing element, respectively. In the presence of DON, the aptamers of DON and cyt c were specifically bound with the DON and induced cyt c, leading to the dissociation of aptamers from the porous surface of the probes. The gate was subsequently opened to release methylene blue (MB) and Rhodamine 6G (Rh6G), and their fluorescence (emission of MB at 700 nm and Rh6G at 550 nm) significantly recovered within 6 h. Cell imaging successfully monitored the exposure of DON and the biological process of cyt c discharge triggered by the activation of the DON-induced apoptosis pathway. In addition, the response between DON and cyt c was observed during the apoptosis process, which is of high significance for the comprehensive and systematic development of mycotoxins cytotoxicity.


Asunto(s)
Aptámeros de Nucleótidos , Tricotecenos , Zeolitas , Citocromos c/metabolismo , Tricotecenos/toxicidad
8.
Anal Bioanal Chem ; 413(19): 4855-4863, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34110440

RESUMEN

Acyclic guanosine analogues, a class of widely used antiviral drugs, can cause chronic toxicity and virus resistance. Therefore, it is essential to establish rapid and accurate methods to detect acyclic guanosine analogues. In this study, five acyclic guanosine analogues (acyclovir, famciclovir, ganciclovir, penciclovir, and valaciclovir) were used as positive targets to obtain broad-spectrum aptamers through Capture-SELEX technology. Real-time quantitative PCR (Q-PCR) was used to monitor the aptamer SELEX process. After the sixteen rounds of selection against mixed targets, sequences were obtained by high-throughput sequencing (HTS). Furthermore, a broad-spectrum aptamer, named CIV6, was found as the higher performance aptamer that was suitable for five acyclic guanosine analogues by graphene oxide (GO) polarization and fluorescence assay. Finally, the aptamer CIV6 was used to construct GO fluorescence assay to detect five acyclic guanosine analogues. The limits of detection (LOD) of acyclovir, famciclovir, ganciclovir, penciclovir, and valaciclovir were 0.48 ng·mL-1, 0.53 ng·mL-1, 0.50 ng·mL-1, 0.56 ng·mL-1, and 0.38 ng·mL-1, respectively.


Asunto(s)
Guanosina/análogos & derivados , Técnica SELEX de Producción de Aptámeros/métodos , Aptámeros de Nucleótidos , ADN de Cadena Simple , Biblioteca de Genes , Guanosina/química , Estructura Molecular , Relación Estructura-Actividad
9.
Phytother Res ; 35(4): 2200-2210, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33258205

RESUMEN

Pancreatic ductal adenocarcinoma (PDAC) is severe malignant tumor in human, the outcomes of PDAC is extremely poor. Here, we evaluated the potential anti-tumor activity of chlorogenic Acid (CA) in PDAC. Here, we found CA was effective to suppress PDAC cell growth in vitro and in vivo. Importantly, we found overall oxygen consumption rate was significantly decreased in CA dose-dependent manner. We also found glycolysis reverse was decreased in CA-treated cells, while basal glycolysis and glycolytic capacity were not significantly changed. Mechanistically, we demonstrated TFR1 could be a novel downstream target of CA, which is essential for PDAC cell growth and cellular bioenergetics maintenance. Furthermore, we validated that CA-reduced c-Myc resulted to down-regulation of TFR1, which contributes to mitochondrial respiration dysfunction and cell growth delay. Together, this study indicates that CA suppresses PDAC cell growth through targeting c-Myc-TFR1 axis and suggests CA could be considered as a promising compound for PDAC treatment.


Asunto(s)
Carcinoma Ductal Pancreático/tratamiento farmacológico , Ácido Clorogénico/química , Metabolismo Energético/genética , Animales , Línea Celular Tumoral , Proliferación Celular , Regulación hacia Abajo , Humanos , Masculino , Ratones , Ratones Desnudos
10.
Anal Biochem ; 608: 113844, 2020 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-32763304

RESUMEN

In this work, a colorimetric aptamer-based method for detection of cadmium using gold nanoparticles modified MoS2 nanocomposites as enzyme mimic is established. In short, biotinylated Cd2+ aptamers are immobilized by biotin-avidin binding on the bottoms of the microplate, the complementary strands of Cd2+ aptamers are connected to the Au-MoS2 nanocomposites which have the function of enhanced peroxidase-like activity. The csDNA-Au-MoS2 signal probe and target Cd2+ compete for binding Cd2+ aptamer, the color change can be observed by addition of chromogenic substrate, thereby realizing visual detection of Cd2+. The absorbance of the solution at 450 nm has a clear linear relationship with the Cd2+ concentration. The linear range is 1-500 ng/mL, and the limit of detection is 0.7 ng/mL. The assay was used to test white wine samples, the results are consistent with those of atomic absorption spectrometry; which prove that this method can be used for detection of Cd2+ in real samples.


Asunto(s)
Aptámeros de Nucleótidos/química , Cadmio/análisis , Cadmio/química , Cationes Bivalentes/análisis , Cationes Bivalentes/química , Colorimetría/métodos , Nanocompuestos/química , Compuestos Cromogénicos/química , ADN Complementario/síntesis química , ADN Complementario/química , Disulfuros/química , Pruebas de Enzimas/métodos , Oro/química , Microscopía Electrónica de Transmisión , Molibdeno/química , Oxidación-Reducción , Peroxidasas/química , Espectrofotometría , Vino/análisis , Difracción de Rayos X
11.
Anal Biochem ; 607: 113893, 2020 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-32739349

RESUMEN

Aptamers are small-sized RNA or ssDNA ligands with a unique structure, which have high specificity and affinity to their cognate targets. Thus, in addition to the extensive values in various bio-medical fields, aptamers can also be alternatively used as affinity ligands in the bioprocess, such as for protein purification. In the present study, a hexahistidine specific aptamer named AptHis-C, was developed through the SELEX methodology, which has high affinity to hexahistidine, and its dissociation constant was as low as 20.8 nM. The structural prediction revealed that AptHis-C contains two connected stem-loop conformations. AptHis-C can only specifically recognize recombinant proteins with the hexahistidine-tag in simple or complex situations, and not to those with other tags. When immobilized on magnetic beads, AptHis-C can be used as a tool for hexahistidine-tagged recombinant protein purification. Its effectiveness is as good as traditional Ni-based beads. Besides, due to the intrinsic characteristics of nucleic acids, such as high thermal/chemical stability, immobilized aptamer-magnetic beads can be reused many times without an obvious decrease of purification effectiveness. This aptamer may represent a novel method for the detection and purification of hexahistidine-tagged recombinant proteins.


Asunto(s)
Aptámeros de Nucleótidos/química , ADN de Cadena Simple/química , Histidina/química , Oligopéptidos/química , Proteínas Recombinantes/aislamiento & purificación , Antígeno B7-H1/genética , Antígeno B7-H1/aislamiento & purificación , Cromatografía de Afinidad , Escherichia coli/química , Escherichia coli/genética , Factor 15 de Diferenciación de Crecimiento/genética , Factor 15 de Diferenciación de Crecimiento/aislamiento & purificación , Imanes/química , Microesferas , Receptor de Muerte Celular Programada 1/genética , Receptor de Muerte Celular Programada 1/aislamiento & purificación , Proteínas Recombinantes/genética , Técnica SELEX de Producción de Aptámeros , Propiedades de Superficie
12.
J Sep Sci ; 43(12): 2467-2476, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32212382

RESUMEN

Dummy template surface molecularly imprinted polymers based on silica gel were prepared through the surface molecular imprinting technique. Nonpoisonous nicotinamide, which is a structural analogue of imidacloprid and acetamidine, was chosen as the dummy template molecule. The obtained polymers were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results showed that the polymers exhibited high adsorption capacity and selectivity for imidacloprid and acetamiprid. The maximum adsorption capacities of the polymers toward imidacloprid and acetamiprid were 42.05 and 22.99 mg/g, and the adsorption could reach binding equilibrium within 150 min. The polymers were successfully applied as column-filling materials to extract imidacloprid and acetamiprid from tea polyphenols with a relatively high removal rate (92.36 and 95.20%). The polymers also showed great stability and reusability during the application. The obtained polymers possessed good application prospects for removing imidacloprid and acetamiprid in tea polyphenol production processes.


Asunto(s)
Polímeros Impresos Molecularmente/química , Neonicotinoides/aislamiento & purificación , Nitrocompuestos/aislamiento & purificación , Polifenoles/química , Dióxido de Silicio/química , Té/química , Geles/química , Estructura Molecular , Neonicotinoides/química , Nitrocompuestos/química , Tamaño de la Partícula , Propiedades de Superficie
13.
Mikrochim Acta ; 187(4): 222, 2020 03 12.
Artículo en Inglés | MEDLINE | ID: mdl-32166414

RESUMEN

This paper describes the fabrication of an imprinted fluorescent nanoprobe based on SiO2-coated NaYF4: Yb, Er upconversion nanoparticles (UCNP) encapsulated with a molecularly imprinted polymer (MIP) for determination of acetamiprid. The fluorescent MIP nanoprobe was prepared using UCNP as the material for fluorescence signal readout, acetamiprid as template molecule, methylacrylic acid (MAA) as functional monomer, and ethyleneglycol dimethacrylate (EGDMA) as cross-linking agent. The molecular imprinting layers were immobilized on the surface of the UCNP@SiO2 by polymerization which occurred between the double bonds. UCNP@MIP shows a high selectivity towards acetamiprid with an imprinting factor (IF) of 7.84. When UCNP@MIP combines with acetamiprid, the fluorescence of the UCNP@MIP can be quenched due to the photo-induced electron transfer. Under optimum conditions, the fluorescence method shows a good linear relationship between the decreased fluorescence intensity (with excitation/emission peaks at 980/542 nm) and the variation of acetamiprid in the concentration range 20 to 800 ng mL-1. The limit of detection (LOD) is 8.3 ng mL-1. This fluorescence method was also successfully applied to detect acetamiprid in apple and strawberry samples. The recoveries range from 89.6 to 97.9%, with relative standard deviations between 1.6 and 2.9% (n = 5). Graphical abstractA simple fluorescence nanoprobe which integrates upconversion nanoparticles (UCNPs) and molecular imprinting polymer (MIP) was developed for the determination of acetamiprid. The limit of the detection was determined as 8.3 ng mL-1. The selectivity was enhanced by molecular imprinting, and the sensitivity was improved by the high sensitivity of the fluorescence emitted from the UCNPs.


Asunto(s)
Técnicas Biosensibles , Fluorometría , Impresión Molecular , Nanopartículas/química , Neonicotinoides/análisis , Adsorción , Fluorescencia , Fluoruros/química , Estructura Molecular , Tamaño de la Partícula , Dióxido de Silicio/química , Propiedades de Superficie , Iterbio/química , Itrio/química
14.
Anal Bioanal Chem ; 411(7): 1453-1465, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30739197

RESUMEN

A rapid and highly sensitive time-resolved fluorescence (TRF)-based aptasensor for simultaneous recognition of mycotoxins ochratoxin A (OTA) and fumonisin B1 (FB1) was developed using multi-color, Ln3+-doped time-resolved fluorescence nanoparticles (TRF-NPs) (NaYF4: Ce, Tb and NH2-Eu/DPA@SiO2 NPs) coupled with complementary strand DNA (cDNA) as luminescence probe and aptamers-conjugated amine-functionalized Fe3O4 magnetic nanoparticles (MNPs) act as a capture probe. Under the optimized conditions, the time-resolved fluorescence intensities at 544 and 618 nm corresponded with Tb3+ and Eu3+, respectively, were used to measure FB1 (Y = 19,177.1 + (- 12,054.4)x, R2 = 0.9917) and OTA (Y = 4138.8 + (- 11,182.6)x, R2 = 0.9924), respectively. The limits of detection (LODs) for FB1 and OTA were 0.019 pg mL-1 and 0.015 pg mL-1, respectively, which were much lower than previously described methods for simultaneous recognition of mycotoxins OTA and FB1 while detection range varied from 0.0001-0.5 ng mL-1. This aptasensor was effectively applied to quantity FB1 and OTA in maize samples and results were compared with ELISA method. This is the first reported time-resolved fluorescence (TRF)-based aptasensor to detect two agriculturally important toxins in the maize. The developed aptasensor has potential to be used for detection of toxins in food safety fields. Graphical abstract.

15.
Mikrochim Acta ; 186(7): 401, 2019 06 10.
Artículo en Inglés | MEDLINE | ID: mdl-31183576

RESUMEN

A method is described for single-step detection of V. parahaemolyticus in seafood via aptamer-based SERS. A gold-coated polydimethylsiloxane (PDMS) film was used for the enhancement of Raman scattering. The Raman reporter 4-mercaptobenzoic acid was linked to aptamer modified gold nanoparticles (AuNPs) served as a signalling probe. The negatively charged signalling probe was assembled onto the cysteamine-modified Au-PDMS film through electrostatic adsorption. On addition of V. parahaemolyticus, it will be bound by the aptamer as a biorecognition element, and this leads to the dissociation of the signalling probe from the Au-PDMS film. Hence, the Raman signal (at 1592 cm-1) decreases. The assay has a wide linear response that covers the 1.2 × 102 to 1.2 × 106 cfu·mL-1 V. parahaemolyticus concentration range. The detection limit is 12 cfu·mL-1. The method was successfully applied to the determination of V. parahaemolyticus in oyster and salmon samples. Graphical abstract Schematic presentation of a surface-enhanced Raman spectroscopic method for single step detection of Vibrio parahaemolyticus using gold coated polydimethylsiloxane as the active substrate and aptamer modified gold nanoparticles. This solid substrate simplified the analysis procedures and enhanced the sensitivity.


Asunto(s)
Aptámeros de Nucleótidos/química , Dimetilpolisiloxanos/química , Oro/química , Nanopartículas del Metal/química , Vibrio parahaemolyticus/química , Secuencia de Bases , Benzoatos/química , Técnicas Biosensibles/métodos , Cisteamina/química , Escherichia coli/química , Límite de Detección , Listeria monocytogenes/química , Salmonella typhimurium/química , Sensibilidad y Especificidad , Espectrometría Raman , Staphylococcus aureus/química , Compuestos de Sulfhidrilo/química , Vibrio parahaemolyticus/aislamiento & purificación
16.
Mikrochim Acta ; 185(6): 304, 2018 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-29777309

RESUMEN

An F0F1-ATPase-based aptasensor is described for the fluorometric determination of Vibrio parahaemolyticus. Chromatophores containing F0F1-ATPases were first prepared from Rhodospirillum rubrum cells. Then, an aptamer-functionalized chromatophore acts as the capture probe, and a chromatophore labeled with the pH probe fluorescein acts as the signalling probe. In the presence of V. parahaemolyticus, the rotation rate of F0F1-ATPase is decreased due to the formation of the aptamer-chromatophore complex. This leads to a retarded proton flux out of the chromatophores. As a result, the pH value inside the chromatophores is reduced, and the fluorescence of the pH probe F1300 is accordingly decreased. The relative fluorescence varies linearly over the 15 to 1.5 × 106 cfu·mL-1 Vibrio parahaemolyticus concentration range, and the limit of detection is 15 cfu·mL-1. The method was applied to analyze artificially contaminated salmon samples where it showed excellent perfomance. Graphical abstract In this assay, aptamer functionalized chromatophores act as a capture probe, and the fluoresce in labeled chromatophores as signalling probe. The formation of aptamer-chromatophore complex leads to a retarded proton flux out of the chromatophores. As a result, the pH value inside the chromatophores is reduced, and fluorescence intensity is accordingly decreased.

17.
Mikrochim Acta ; 185(11): 497, 2018 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-30291459

RESUMEN

An aptamer-based test strip is described for visual and instrumental determination of the mycotoxin ochratoxin A (OTA). It is based on the use of NaYF4:Yb,Er upconversion nanoparticles (UCNPs) as a label for the aptamer and on the competition between OTA and its complementary sequence for an OTA-specific aptamer. To improve the analytical performance, the optical properties of the UCNPs, the fluidity of the UCNP-aptamer conjugate, and the migration rate on the nitrocellulose membranes were investigated. Under the optimal experimental conditions and by using a 980-nm laser, the relative fluorescence intensity (test line value/control line value) is proportional to the logarithm of the OTA concentration over a range from 5 to 100 ng·mL-1 (R2 = 0.9955). The limit of the detection is 1.86 ng·mL-1. This aptamer based flow assay can be performed within 15 min and has no serious cross-sensitivity to potentially interfering species. It was successfully applied to the determination of OTA in spiked wheat and beer samples. Graphical abstract An aptamer-based upconversion fluorescent strip based on the use of NaYF4:Yb,Er nanoparticles was developed for sensitive detection of Ochratoxin A. The limit of the detection was determined as 1.86 ng·mL-1. The assay can be performed within 15 min, indicating its great potential in point-of-care testing.


Asunto(s)
Aptámeros de Nucleótidos/química , Técnicas Biosensibles/métodos , Nanopartículas/química , Ocratoxinas/análisis , Límite de Detección , Modelos Moleculares , Conformación de Ácido Nucleico , Ocratoxinas/metabolismo , Tiras Reactivas/química , Espectrometría de Fluorescencia
18.
Anal Biochem ; 508: 58-64, 2016 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-27318239

RESUMEN

Patulin (PAT) is a kind of mycotoxin that has serious harmful impacts on both food quality and human health. A high-affinity ssDNA aptamer that specifically binds to patulin was generated using systemic evolution of ligands by exponential enrichment (SELEX) assisted by graphene oxide (GO). After 15 rounds of positive and negative selection, a highly enriched ssDNA pool was sequenced and the representative sequences were subjected to binding assays to evaluate their affinity and specificity. Of the eight aptamer candidates tested, the sequence PAT-11 bound to patulin with high affinity and excellent selectivity with a dissociation constant (Kd) of 21.83 ± 5.022 nM. The selected aptamer, PAT-11, was subsequently used as a recognition element to develop a detection method for patulin based on an enzyme-chromogenic substrate system. The colorimetric aptasensor exhibited a linear range from 50 to 2500 pg mL(-1), and the limit of detection was found to be 48 pg mL(-1). The results indicated that GO-SELEX technology was appropriate for the screening of aptamers against small-molecule toxins, offering a promising application for aptamer-based biosensors.


Asunto(s)
Aptámeros de Nucleótidos/química , Técnicas de Química Analítica/métodos , Colorimetría , Patulina/análisis , Humanos , Mutágenos/análisis
19.
Analyst ; 141(13): 3942-61, 2016 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-27265444

RESUMEN

Food safety is a global health objective, and foodborne diseases represent a major crisis in health. Techniques that are simple and suitable for fast screening to detect and identify pathogenic factors in the food chain are vital to ensure food safety. At present, a variety of analytical methods have been reported for the detection of pathogenic agents. Whereas the sensitivity of detection and quantification are still important challenges, we expect major advances from new assay formats and synthetic bio-recognition elements, such as aptamers. Owing to the specific folding capability of aptamers in the presence of an analyte, aptasensors have substantially and successfully been exploited for the detection of a wide range of small and large molecules (e.g., toxins, antibiotics, heavy metals, bacteria, viruses) at very low concentrations. Here, we review the use of aptasensors for the development of highly sensitive and affordable detection tools for food analysis.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Contaminación de Alimentos/análisis , Inocuidad de los Alimentos
20.
Anal Bioanal Chem ; 408(14): 3823-31, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-27007737

RESUMEN

A novel aptasensor labeled with Mn(2+)-doped NaYF4:Yb/Er upconversion nanoparticles (NaYF4:Yb,Er/Mn UCNPs) was employed in electrogenerated chemiluminescence (ECL) for the sensitive detection of bisphenol A (BPA). The ECL aptasensor was assembled by immobilizing the thiolated aptamers of BPA covalently on a gold nanoparticle (AuNPs)-modified electrode and pairing with complementary DNA labeled with NaYF4:Yb,Er/Mn UCNPs. The ECL aptasensor can not only rapidly and accurately detect BPA concentrations from 0.05 to 100 ng/mL with a detection limit of 0.037 ng/mL but also provides a new platform for ECL applications based on the use of upconversion nanoparticles as a promising alternative material. Graphical Abstract The NaYF4:Yb,Er/Mn UCNPs combining with the BPA aptamer serving as recognition elements create a ECL platform for the sensitive detection of bisphenol A. The change in ECL signals induced by aptamer-target interactions was measured and a significant decrease in intensity was found on interaction with BPA in the concentration range of 0.05 to 100 ng/mL.


Asunto(s)
Compuestos de Bencidrilo/análisis , Erbio/química , Fluoruros/química , Manganeso/química , Fenoles/análisis , Iterbio/química , Itrio/química , Electroquímica , Límite de Detección , Luminiscencia
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