The hygienic quality of urban surfaces can be impaired by multiple sources of microbiological contaminants. These surfaces can trigger the development of multiple bacterial taxa and favor their spread during rain events through the circulation of runoff waters. These runoff waters are commonly directed toward sewer networks, stormwater infiltration systems or detention tanks prior a release into natural water ways.
View Article and Find Full Text PDFMercury (Hg) is naturally released by volcanoes and geothermal systems, but the global flux from these natural sources is highly uncertain due to a lack of direct measurements and uncertainties with upscaling Hg/SO mass ratios to estimate Hg fluxes. The 2021 and 2022 eruptions of Fagradalsfjall volcano, southwest Iceland, provided an opportunity to measure Hg concentrations and fluxes from a hotspot/rift system using modern analytical techniques. We measured gaseous Hg and SO concentrations in the volcanic plume by near-source drone-based sampling and simultaneous downwind ground-based sampling.
View Article and Find Full Text PDFCities are patchworks of urban catchments divided into functional units according to their commercial, residential and industrial activities, and socio-urbanistic patterns. The hypothesis of city surface microbiomes being structured by socio-urbanistic variables leading to an emergence of synurbic taxa was tested. According to the r/K microbial ecology theory, a gradient of well-adapted synurbic K-strategists and of opportunistic -r-strategists should occur over city surfaces.
View Article and Find Full Text PDFDespite an increasing level of evidence supporting the individual beneficial effect of polyphenols on cognitive performance, information related to the potential synergistic action of these phytonutrients on cognitive performance during a prolonged cognitive effort is currently lacking. This study investigated the acute and sustained action of a polyphenols-rich extract from grape and blueberry (PEGB), on working memory and attention in healthy students during a prolonged and intensive cognitive effort. In this randomised, cross-over, double blind study, 30 healthy students consumed 600 mg of PEGB or a placebo.
View Article and Find Full Text PDFThree-dimensional (3D) printing technologies will impact the biosensor community in the near future, at both the sensor prototyping level and the sensing layer organization level. The present study aimed at demonstrating the capacity of one 3D printing technique, digital light processing (DLP), to produce hydrogel sensing layers with 3D shapes that are unattainable using conventional molding procedures. The first model of the sensing layer was composed of a sequential enzymatic reaction (glucose oxidase and peroxidase), which generated a chemiluminescent signal in the presence of glucose and luminol.
View Article and Find Full Text PDFThirty-five blood group systems, containing >300 antigens, are listed by the International Society of Blood Transfusion. Most of these antigens result from a single nucleotide polymorphism. Blood group typing is conventionally performed by serology.
View Article and Find Full Text PDFOwing 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.
View Article and Find Full Text PDFOwing 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.
View Article and Find Full Text PDFThis study aims to investigate gadolinium-based nanoparticles (Gd-HNP) for in vitro labeling of human plasmacytoid dendritic cells (HuPDC) to allow for in vivo tracking and HuPDC quantifying using magnetic resonance imaging (MRI) following parenteral injection. Human plasmacytoid DC were labeled (LabHuPDC) with fluorescent Gd-HNP (Gd-FITC-HNP) and injected via intraperitoneal and intravenous routes in 4-5 NOD-SCID β2m(-/-)mice (treated mice = TM). Control mice (CM) were similarly injected with unlabeled HuPDC.
View Article and Find Full Text PDFThe present report describes the integration and application possibilities of a new microarray concept based on adhesive surface. The method was shown to enable the straightforward production of 384 and 1536-well plates modified with 100 and 25 spots per well, respectively. Such in-well densities were only possible thanks to the fabrication process which implies first the deposition of the microarray on a flat adhesive surface and then its assembly with bottomless 384 or 1536-well plates.
View Article and Find Full Text PDFWe 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.
View Article and Find Full Text PDFWe are reporting here a new technology for the straightforward production of integrated microarrays. The approach is based on the use of adhesive supports enabling (i) the immobilization of biomolecules as microarrays (up to 2500 spots per cm(2)) and (ii) the easy assembly of these microarrays with complex 3D structures such as 96-well bottomless microplates or polymer and glass microfluidic networks. The analytical performances of the system were demonstrated for sandwich protein detection (C-reactive protein) and hybridization assays, both in classical 96-well microplate format and microfluidic environment.
View Article and Find Full Text PDFA new approach for the rapid production of microfluidic chips integrating protein spots is described. The technology, called "Print-n-Shrink", is based on the screen-printing of a microfluidic design (using a dielectric ink) onto Polyshrink™ polystyrene sheets. The initial printing which have a minimum size of 15 μm (height)×230 μm (width) was thermally treated (30s, 163°C) to shrink and generate features of 85 μm (height)×100 μm (width).
View Article and Find Full Text PDFAn innovative method for the production of microfluidic chips integrating protein spots is described. The technology, called "Print-n-Shrink", is based on the screen-printing of a microfluidic design (using a dielectric ink) onto Polyshrink polystyrene sheets. The initial print which has a minimum size of 15 microm (height) x 230 microm (width) is thermally treated (30 seconds, 163 degrees C) to shrink and generate features of 85 microm (height) x 100 microm (width).
View Article and Find Full Text PDFA method for the immobilization of proteins at the surface of surface plasmon resonance imaging (SPRi) chips is presented. The technology, based on the electro-deposition of a 4-carboxymethyl aryl diazonium (CMA) monolayer is compared to a classical thioctic acid self-assembled monolayer. SPRi live recording experiments followed by the quantification of the diazonium surface coverage demonstrate the presence of a monolayer of electro-deposited molecules (11*10(12) molecules mm(-2)).
View Article and Find Full Text PDFBiosens Bioelectron
January 2009
"Macromolecules to PDMS transfer" technique relying on the direct entrapment of macromolecules spots during PDMS polymerisation is proposed as an alternative for the easy and simple PDMS surface modification. In the present work, the development of three different applications based on this procedure is presented as proof of the method potentialities. First, C-reactive protein (CRP) sandwich immunoassay using immobilised monoclonal anti-CRP antibodies was developed for sepsis diagnosis.
View Article and Find Full Text PDFFunctionalized gold nanoparticles were applied as contrast agents for both in vivo X-ray and magnetic resonance imaging. These particles were obtained by encapsulating gold cores within a multilayered organic shell which is composed of gadolinium chelates bound to each other through disulfide bonds. The contrast enhancement in MRI stems from the presence of gadolinium ions which are entrapped in the organic shell, whereas the gold core provides a strong X-ray absorption.
View Article and Find Full Text PDFDetection of toxic substances interfering with endocrine system is one of the major preoccupations of the European community. A whole-cell bioassay for pollution detection based on stress induction has been designed. Well characterized toxicants, cadmium chloride and thiram (a dithiocarbamate fungicide), were used to optimize the detection conditions such as time-course conditions, cell line and reporter gene to be used.
View Article and Find Full Text PDFBiochem Biophys Res Commun
September 2005
A whole-cell bioassay has been developed for the total toxicity testing of liquid samples. The method is based on the induction of the bioluminescent activity of genetically manipulated mammalian cells. For that purpose, transfection was used to introduce, in HeLa cells, a DNA sensing element that responds to chemical stress agents (heavy metals, genotoxic agents, and endocrine-disrupting chemicals).
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