The Experts below are selected from a list of 8640 Experts worldwide ranked by ideXlab platform
Valérie Pichon - One of the best experts on this subject based on the ideXlab platform.
-
Miniaturized DNA aptamer-based monolithic sorbent for selective extraction of a Target Analyte coupled on-line to nanoLC
Analytical and Bioanalytical Chemistry, 2014Co-Authors: Fabien Brothier, Valérie PichonAbstract:A complete characterization of a novel Target-specific DNA aptamer-based miniaturized solid phase extraction (SPE)-sorbent coupled on-line to nanoLC is presented. A miniaturized oligosorbent (mOS) was prepared via the in situ sol-gel synthesis of a hybrid organic-inorganic monolith in 100 μm i.d. capillary columns using tetraethoxysilane and 3-aminopropyltriethoxysilane as precursors, followed by covalent binding of a 5′-amino-modified DNA aptamer with a C12 spacer arm specific for a molecule of small molecular weight. Ochratoxin A (OTA), one of the most abundant naturally occurring mycotoxins, was chosen as model Analyte to demonstrate the principle of such an approach. The mOS was coupled on-line to RP-nanoLC-LIF. Selective extraction of OTA on several mOSs was demonstrated with an average extraction recovery above 80 % when percolating spiked binding buffer and a low recovery on control monoliths grafted with a non-specific aptamer. Reproducibility of mOSs preparation was highlighted by comparing extraction yields. Otherwise, the mOSs demonstrated no cross-reactivity towards an OTA structural analogue, i.e., ochratoxin B. Due to the high specific surface area of the hybrid silica-based monolith, the coverage density of DNA aptamers covalently immobilized in the capillaries was very high and reached 6.27 nmol μL^−1, thus leading to a capacity above 5 ng of OTA. This miniaturized device was then applied to the selective extraction of OTA from beer samples. It revealed to be effective in isolating OTA from this complex matrix, thus improving the reliability of its analysis at the trace level.
-
miniaturized dna aptamer based monolithic sorbent for selective extraction of a Target Analyte coupled on line to nanolc
Analytical and Bioanalytical Chemistry, 2014Co-Authors: Fabien Brothier, Valérie PichonAbstract:A complete characterization of a novel Target-specific DNA aptamer-based miniaturized solid phase extraction (SPE)-sorbent coupled on-line to nanoLC is presented. A miniaturized oligosorbent (mOS) was prepared via the in situ sol-gel synthesis of a hybrid organic-inorganic monolith in 100 μm i.d. capillary columns using tetraethoxysilane and 3-aminopropyltriethoxysilane as precursors, followed by covalent binding of a 5′-amino-modified DNA aptamer with a C12 spacer arm specific for a molecule of small molecular weight. Ochratoxin A (OTA), one of the most abundant naturally occurring mycotoxins, was chosen as model Analyte to demonstrate the principle of such an approach. The mOS was coupled on-line to RP-nanoLC-LIF. Selective extraction of OTA on several mOSs was demonstrated with an average extraction recovery above 80 % when percolating spiked binding buffer and a low recovery on control monoliths grafted with a non-specific aptamer. Reproducibility of mOSs preparation was highlighted by comparing extraction yields. Otherwise, the mOSs demonstrated no cross-reactivity towards an OTA structural analogue, i.e., ochratoxin B. Due to the high specific surface area of the hybrid silica-based monolith, the coverage density of DNA aptamers covalently immobilized in the capillaries was very high and reached 6.27 nmol μL−1, thus leading to a capacity above 5 ng of OTA. This miniaturized device was then applied to the selective extraction of OTA from beer samples. It revealed to be effective in isolating OTA from this complex matrix, thus improving the reliability of its analysis at the trace level.
-
selective and automated sample pretreatment by molecularly imprinted polymer for the analysis of the basic drug alfuzosin from plasma
Journal of Chromatography A, 2008Co-Authors: F Hugonchapuis, J U Mullot, G Tuffal, Marieclaire Hennion, Valérie PichonAbstract:Abstract A molecularly imprinted polymer synthesized in dichloromethane, was evaluated for the selective extraction of a pharmaceutical compound from human plasma and integrated on-line with liquid chromatography. The Target drug is an α-blocker called alfuzosin widely used for the treatment of benign prostatic hyperplasia. By a comprehensive approach of the retention mechanism, a selective extraction procedure was established by exploiting the development of electrostatic interactions between the Target Analyte and the selective support in LC compatible solvents. By applying this method to plasma, extraction recoveries close to 100% were obtained for alfuzosin while various pharmaceutical compounds currently found in biological fluids were not retained on the support. The high selectivity of the support coupled to the chromatographic system permitted an easy and fast analysis of the drug with a limit of quantification of 15 μg L−1 by UV detection.
Karsten Haupt - One of the best experts on this subject based on the ideXlab platform.
-
Holographic molecularly imprinted polymers for label-free chemical sensing.
Advanced Materials, 2013Co-Authors: Y. Fuchs, O. Soppera, A.g. Mayes, Karsten HauptAbstract:Holographic molecularly imprinted polymer films for the use in chemical sensors are obtained in one step through photopolymerization with interfering laser beams. This results in hierarchical structuring at four length scales: micrometer-scale patterning of millimeter- to centimeter- size polymer objects with holographic optical properties, exhibiting nanometer-scale porosity and specific molecular recognition properties at the molecular scale through self-assembly. Specific binding of the Target Analyte testosterone is measured by diffraction analysis.
-
Molecularly imprinted polymers: synthetic receptors in bioanalysis
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Karsten HauptAbstract:Molecularly imprinted polymers (MIPs) are tailor-made synthetic materials possessing specific cavities designed for a Target molecule. Since they recognise their Target Analyte with affinities and selectivities comparable to those of antibody–antigen, enzyme–substrate and ligand–receptor interactions, they are often referred to as synthetic receptors or plastic antibodies. In this review, we describe the great potential and recent developments of MIPs in affinity separations, with emphasis on their application to the solid-phase extraction (SPE) of Analytes from complex matrices. Research efforts made in this field to obtain water-compatible polymers for their applicability in aqueous environments are described. We particularly discuss problems encountered in the use of MIPs in SPE and the attempts carried out to improve their efficiency. Figure
-
Molecularly imprinted polymers: synthetic receptors in bioanalysis.
Analytical and Bioanalytical Chemistry, 2010Co-Authors: B. Tse Sum Bui, Karsten HauptAbstract:Molecularly imprinted polymers (MIPs) are tailor-made synthetic materials possessing specific cavities designed for a Target molecule. Since they recognise their Target Analyte with affinities and selectivities comparable to those of antibody-antigen, enzyme-substrate and ligand-receptor interactions, they are often referred to as synthetic receptors or plastic antibodies. In this review, we describe the great potential and recent developments of MIPs in affinity separations, with emphasis on their application to the solid-phase extraction (SPE) of Analytes from complex matrices. Research efforts made in this field to obtain water-compatible polymers for their applicability in aqueous environments are described. We particularly discuss problems encountered in the use of MIPs in SPE and the attempts carried out to improve their efficiency.
Pavel Jandera - One of the best experts on this subject based on the ideXlab platform.
-
Molecularly imprinted polymers and their application in solid phase extraction
Journal of Separation Science, 2009Co-Authors: Martina Lasáková, Pavel JanderaAbstract:Solid phase extraction is routinely used in many different areas of analytical chemistry. Some of the main fields are environmental, biological, and food chemistry, where cleaning and pre-concentration of the sample are important steps in the analytical protocol. Molecularly imprinted polymers (MIPs) have attracted attention because they show promise as compound-selective or group-selective media. The application of these synthetic polymers as sorbents allows not only pre-concentration and cleaning of the sample but also selective extraction of the Target Analyte, which is important, particularly when the sample is complex and impurities can interfere with quantification. This review surveys the selectivity of MIPs in solid phase extraction of various kinds of Analytes.
Wolfgang Knoll - One of the best experts on this subject based on the ideXlab platform.
-
magnetic nanoparticle enhanced biosensor based on grating coupled surface plasmon resonance
Analytical Chemistry, 2011Co-Authors: Yi Wang, Jakub Dostalek, Wolfgang KnollAbstract:A highly sensitive surface plasmon resonance (SPR) biosensor employing magnetic nanoparticle (MNP) assays is presented. In the reported approach, MNPs simultaneously served as “vehicles” for rapid delivery of Target Analyte from a sample to the sensor surface and as labels increasing the measured refractive index changes that are associated with the binding of Target Analyte. An optical setup based on grating-coupled surface plasmon resonance (GC-SPR) was used with a magnetic field gradient applied through the sensor chip for manipulating with MNPs on its surface. Iron oxide MNPs and a sensor surface with metallic diffraction grating were modified with antibodies that specifically recognize different epitopes of the Analyte of interest. The sensitivity of the biosensor was investigated as a function of mass transport of the Analyte to the sensor surface driven by diffusion (free Analyte) or by the magnetic field gradient (Analyte bound to MNPs). Immunoassay-based detection of β human chorionic gonadotropi...
Daqian Song - One of the best experts on this subject based on the ideXlab platform.
-
Ultrasensitive magnetic field-assisted surface plasmon resonance immunoassay for human cardiac troponin I
Biosensors and Bioelectronics, 2017Co-Authors: Qiong Wu, Di Zhang, Shuo Li, Yue Zhang, Pinyi Ma, Yang Yu, Xinghua Wang, Daqian SongAbstract:Abstract An ultrasensitive surface plasmon resonance (SPR) immunoassay was developed for the specific detection of human cardiac troponin I (cTnI), a principle diagnostic marker for myocardial damage. The thin gold film evaporated on a glass slate, which was employed as the SPR sensing film, was modified by hollow gold nanoparticles (HGNPs) and polydopamine (PDA) sequentially, and then was immobilized with antibodies for specific recognition of Target Analyte. Electronic coupling of the surface plasmon waves originating from the HGNPs and the gold film leads to the remarkable amplification of SPR response. The PDA film modified on the gold film via self-polymerization of dopamine (DA) facilitates the direct immobilization of capture antibodies (cAb). To separate and enrich the Target Analyte, PDA-wrapped magnetic multi-walled carbon nanotubes (MMWCNTs-PDA) were conjugated with detection antibodies (dAb) and used as the extracting agent for the magnetic extraction of cTnI in sample. Large surface area of MMWCNTs-PDA ensures its loading capacity for dAb, as well as its extraction efficiency for cTnI. By serving as the “vehicles” for fast delivering the concentrated Analyte to the SPR sensing surface, MMWCNTs-PDA-dAb also overcomes the disadvantage of slow diffusion-limited mass transfer and matrix interference effect in regular patterns. The combination of the above improvements results in the significant sensitivity enhancement of the SPR immunoassay. The concentration of cTnI with minimum detectable SPR response obtained by the present assay is 1.25 ng mL −1 , which is 1000-fold lower than that obtained by the traditional SPR immunoassay based on PDA-modified gold film.
