Time filter

Source Type

Sainte-Foy-lès-Lyon, France

Desmet C.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Blum L.J.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Marquette C.A.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Marquette C.A.,AXO Science SAS
Analytical Chemistry

The present study described the development and evaluation of a new fully automated multiplex competitive immunoassay enabling the simultaneous detection of five water pollutants (okadaic acid (OA), 2-chloro-4-ethylamino-6- isopropylamino-1,3,5-triazine (atrazine), 2.4-dichlorophenoxyacetic acid (2,4-D), 2,4,6-trinitrotoluene (TNT), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX)). The technology is taking advantage of an optical-clear pressure-sensitive adhesive on which biomolecules can be immobilized and that can be integrated within a classical 96-well format. The optimization of the microarray composition and cross-reaction was performed using an original approach where probe molecules (haptens) were conjugated to different carriers such as protein (bovine serum albumin or ovalbumin), amino-functionalized latex beads, or dextran polymer and arrayed at the surface of the adhesive. A total of 17 different probes were then arrayed together with controls on the adhesive surface and screened toward their specific reactivity and cross-reactivity. Once optimized, the complete setup was used for the detection of the five target molecules (less than 3 h for 96 samples). Limits of detection of 0.02, 0.01, 0.01, 100, and 0.02 μg L-1 were found for OA, atrazine, 2,4-D, TNT, and RDX, respectively. The proof of concept of the multiplex competitive detection (semiquantitative or qualitative) of the five pollutants was also demonstrated on 16 spiked samples. © 2012 American Chemical Society. Source

Boccoz S.A.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Boccoz S.A.,AXO Science SAS | Blum L.J.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Marquette C.A.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry

At present, 33 blood groups representing over 300 antigens are listed by the International Society of Blood Transfusion (ISBT). Most of them result from a single nucleotide polymorphism (SNP) in the corresponding DNA sequence, i.e. approx. 200 SNPs. In immunohematology laboratories, blood group determination is classically carried out by serological tests, but these have some limitations, mostly in term of multiplexing and throughput. Yet, there is a growing need of extended blood group typing to prevent alloimmunization in transfused patients and transfusion accidents. The knowledge of the molecular bases of blood groups allows the use of molecular biology methods within immunohematology laboratories. Numerous assays focused on blood group genotyping were developed and described during the last 10. years. Some of them were real biochips or biosensors while others were more characterized by the particular molecular biology techniques they used, but all were intending to produce multiplex analysis. PCR techniques are most of the time used followed by an analytical step involving a DNA biosensor, biochip or analysis system (capillary electrophoresis, mass spectrometry). According to the method used, the test can then be classified as low-, medium- or high-throughput. There are several companies which developed platforms dedicated to blood group genotyping able to analyze simultaneously various SNPs or variants associated with blood group systems.This review summarizes the characteristics of each molecular biology method and medium-/high-throughput platforms dedicated to the blood group genotyping. © 2013 Elsevier Inc. Source

Desmet C.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Blum L.J.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Marquette C.A.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Marquette C.A.,AXO Science SAS
Environmental Sciences: Processes and Impacts

The present study describes the development, optimization and performance comparison of three ELISAs and one multiplex immunoassay in a microarray format. The developed systems were dedicated to the detection of three different classes of pollutants (pesticide, explosive and toxin) in water. The characteristics and performances of these two types of assays were evaluated and compared, in order to verify that multiplex immunoassays can replace ELISA for multiple analyte sensing. 2,4-Dichlorophenoxyacetic acid, 2,4,6-trinitrotoluene and okadaic acid were chosen as model targets and were immobilized in classical microtiter plate wells or arrayed at the surface of a microarray integrated within a classical 96-well plate. Once optimized, the classical ELISAs and microarray-based ELISA performances were evaluated and compared in terms of limit of detection, IC50, linearity range and reproducibility. Classical ELISAs provided quite good sensitivity (limit of detection down to 10 μg L-1), but the multiplex immunoassay was proven to be more sensitive (limit of detection down to 0.01 μg L-1), more reproducible and an advantageous tool in terms of cost and time expenses. This multiplex tool was then used for the successful detection of the three target molecules in spiked water samples and achieved very promising recovery rates. © 2013 The Royal Society of Chemistry. Source

Miladi I.,CNRS Laboratory of Physical Chemistry of Luminescent Materials | Miladi I.,French Institute of Health and Medical Research | Alric C.,CNRS Laboratory of Physical Chemistry of Luminescent Materials | Dufort S.,Nano H S.A.S | And 18 more authors.

The gadolinium chelate coated gold nanoparticles (Au@DTDTPA-Gd 50) which were designed as contrast agents for magnetic resonance imaging (MRI) also behave as radiosensitizers. Their follow-up by MRI allows determining the delay between the irradiation of the tumor and the injection of the nanoparticles. As a result, the use of Au@DTDTPA-Gd50 nanoparticles leads to the improvement of the effect of radiotherapy. Owing to the high atomic number (Z) of gold element, the gold nanoparticles appear as very promising radiosensitizing agents. This character can be exploited for improving the selectivity of radiotherapy. However, such an improvement is possible only if irradiation is performed when the gold content is high in the tumor and low in the surrounding healthy tissue. As a result, the beneficial action of irradiation (the eradication of the tumor) should occur while the deleterious side effects of radiotherapy should be limited by sparing the healthy tissue. The location of the radiosensitizers is therefore required to initiate the radiotherapy. Designing gold nanoparticles for monitoring their distribution by magnetic resonance imaging (MRI) is an asset due to the high resolution of MRI which permits the accurate location of particles and therefore the determination of the optimal time for the irradiation. We recently demonstrated that ultrasmall gold nanoparticles coated by gadolinium chelates (Au@DTDTPA-Gd) can be followed up by MRI after intravenous injection. Herein, Au@DTDTPA and Au@DTDTPA-Gd were prepared in order to evaluate their potential for radiosensitization. Comet assays and in vivo experiments suggest that these particles appear well suited for improving the selectivity of the radiotherapy. The dose which is used for inducing similar levels of DNA alteration is divided by two when cells are incubated with the gold nanoparticles prior to the irradiation. Moreover, the increase in the lifespan of tumor bearing rats is more important when the irradiation is performed after the injection of the gold nanoparticles. In the case of treatment of rats with a brain tumor (9L gliosarcoma, a radio-resistant tumor in a radiosensitive organ), the delay between the intravenous injection and the irradiation was determined by MRI. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Le Goff G.C.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Corgier B.P.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | Corgier B.P.,AXO Science SAS | Mandon C.A.,CNRS Institute of Molecular and Supramolecular Chemistry and Biochemistry | And 4 more authors.
Biosensors and Bioelectronics

We report here a comparison of support materials for colorimetric hybridization assays on microarrays. Four surfaces with various chemistries and architectures (roughness and porosity) were evaluated: (i) bare and (ii) activated polystyrene surfaces classically used for ELISA; (iii) a double-sided adhesive support; and (iv) a porous nitrocellulose/cellulose acetate membrane. Each substrate was functionalized with a microarray of probes and subjected to an enzymatic colorimetric DNA hybridization test. Tests were carried out in a 96-well assembly suitable for automated high-throughput analysis. Colorimetry results, microscopy observations and a chemiluminescence study showed that the test efficiency not only depends on the surface probe density but that the capacity of the material to retain the colored enzymatic product is also a critical parameter. All parameters being considered, the adhesive coated surface proposes the best surface properties for efficient colorimetric microarrays. © 2012 Elsevier B.V.. Source

Discover hidden collaborations