Guillaume Suarez - Academia.edu (original) (raw)

Papers by Guillaume Suarez

Langmuir, 2010

The present work describes a methodology for patterning biomolecules on silicon-based analytical ... more The present work describes a methodology for patterning biomolecules on silicon-based analytical devices that reconciles 3-D biological functionalization with standard resist lift-off techniques. Unlike classic sol-gel approaches in which the biomolecule of interest is introduced within the sol mixture, a two-stage scenario has been developed. It consists first of patterning micrometer/submicrometer polycondensate scaffold structures, using classic microfabrication tools, that are then loaded with native biomolecules via a second simple incubation step under biologically friendly environmental conditions. The common compatibility issue between the biological and microfabrication worlds has been circumvented because native recognition biomolecules can be introduced into the host scaffold downstream from all compatibility issues. The scaffold can be generated on any silicon substrate via the polycondensation of aminosilane, namely, aminopropyltriethoxy silane (APTES), under conditions that are fully compatible with resist mask lithography. The scaffold porosity and high primary amine content allow proteins and nucleic acid sequences to penetrate the polycondensate and to interact strongly, thus giving rise to micrometer/submicrometer 3-D structures exhibiting high biological activity. The integration of such a biopatterning approach in the microfabrication process of silicon analytical devices has been demonstrated via the successful completion of immunoassays and nucleic acid assays.

Les cahiers de la Recherche. Santé, Environnement, Travail, Jun 1, 2018

Antioxidants

Exhaled breath condensate (EBC) has attracted substantial interest in the last few years, enablin... more Exhaled breath condensate (EBC) has attracted substantial interest in the last few years, enabling the assessment of airway inflammation with a non-invasive method. Concentrations of 8-Hydroxydesoxyguanosine (8-OHdG) and 8-isoprostane in EBC have been suggested as candidate biomarkers for lung diseases associated with inflammation and oxidative stress. EBC is a diluted biological matrix and consequently, requires highly sensitive chemical analytic methods (picomolar range) for biomarker quantification. We developed a new liquid chromatography coupled to tandem mass spectrometry method to quantify 8-OHdG and 8-isoprostane in EBC simultaneously. We applied this novel biomarker method in EBC obtained from 10 healthy subjects, 7 asthmatic subjects, and 9 subjects with chronic obstructive pulmonary disease. Both biomarkers were below the limit of detection (LOD) despite the good sensitivity of the chemical analytical method (LOD = 0.5 pg/mL for 8-OHdG; 1 pg/mL for 8-isoprostane). This la...

e aim of the symposium is to provide a scienti c forum for researchers and practitioners to prese... more e aim of the symposium is to provide a scienti c forum for researchers and practitioners to present and discuss the latest researches on occupational and environmental health issues of nanotechnolog y. Nanomaterial processing and characterization Health effects and toxicity (in vivo, in vitro) of manufactured nanomaterials ADME (Absorption, distribution, metabolism and excretion) and methodology for kinetic study of manufactured nanomaterials Environmental toxicity of manufactured nanomaterials Exposure assessment in the workplaces producing or handling manufactured nanomaterials Risk assessment of manufactured nanomaterials Risk management of manufactured nanomaterials Outreach for occupational and environmental health in nanotechnology Epidemiology on the workers exposed to manufactured nanomaterials Worker protection: Identifying and training the nanomaterial workforce

Sustainability

We developed a Bayesian spline model for real-time mass concentrations of particulate matter (PM1... more We developed a Bayesian spline model for real-time mass concentrations of particulate matter (PM10, PM2.5, PM1, and PM0.3) measured simultaneously in the personal breathing zone of Parisian subway workers. The measurements were performed by GRIMM, a gravimetric method, and DiSCmini during the workers’ work shifts over two consecutive weeks. The measured PM concentrations were analyzed with respect to the working environment, the underground station, and any specific events that occurred during the work shift. Overall, PM0.3 concentrations were more than an order of magnitude lower compared to the other PM concentrations and showed the highest temporal variation. The PM2.5 levels raised the highest exposure concern: 15 stations out of 37 had higher mass concentrations compared to the reference. Station PM levels were not correlated with the annual number of passengers entering the station, the year of station opening or renovation, or the number of platforms and tracks. The correlati...

Medicine in Novel Technology and Devices, 2022

Exposure day: complementary table to main results, TableÂ 4. Coefficients with standard error and... more Exposure day: complementary table to main results, TableÂ 4. Coefficients with standard error and p-value for the different mixed models used for explaining the evolution of oxidative stress biomarkers in EBC, plasma and creatinine-corrected urine. *Indicates significant increase at the time point as compared to T1. +Total reducing capacity concentration was measured in whole blood and not plasma. (DOC 47Â kb)

Percentage of samples with concentrations below the Limit of Detection (LOD) for biomarkers in bi... more Percentage of samples with concentrations below the Limit of Detection (LOD) for biomarkers in biological liquids, in total. +Total reducing capacity concentration was measured in whole blood and not plasma. (DOC 29Â kb)

Control day: Median concentrations of oxidative stress biomarkers in EBC, plasma and creatinine c... more Control day: Median concentrations of oxidative stress biomarkers in EBC, plasma and creatinine corrected urine (respective unit/g creatinine), presented by time point. EBC was not assessed for 8-OHdG concentrations. +Total reducing capacity concentration was measured in whole blood and not plasma. (DOC 47Â kb)

Archives Des Maladies Professionnelles Et De L Environnement, 2018

Contexte La prevention des effets respiratoires lies aux expositions professionnelles a des aeroc... more Contexte La prevention des effets respiratoires lies aux expositions professionnelles a des aerocontaminants est un enjeu important pour les medecins du travail. Entre 20 et 30 % des bronchites chroniques obstructives (BPCO) sont liees a des expositions professionnelles, comme les particules fines ou ultrafines, qui peuvent induire un stress oxydant. Des biomarqueurs du stress oxydant pourraient etre proposes pour le depistage precoce des effets respiratoires, notamment de la BPCO, a condition d’etre valides et mesurables dans des prelevements biologiques peu invasifs. Methodes Une revue de litterature sur les biomarqueurs pertinents pour la surveillance de travailleurs a ete realisee, puis un projet de recherche collaborative entre l’IST et l’UPST-RATP a ete propose pour selectionner et valider les biomarqueurs du stress oxydatif non invasifs. Resultats Le projet Respiratory disease Occupational Biomonitoring Collaborative Project (ROBoCop) est bâti dans le cadre du consortium euro...

En la presente Tesis Doctoral se ha llevado a cabo el diseno y desarrollo de arquitecturas molecu... more En la presente Tesis Doctoral se ha llevado a cabo el diseno y desarrollo de arquitecturas moleculares organizadas basadas en interacciones electrostaticas para la construccion de biosensores amperometicos. La sintesis, caracterizacion y optimizacion del modulo electroquimico, junto con la manipulacion de la carga neta de los diferentes polielectrolitos manteniendo sus actividad o propiedades redox ha permitido la construccion de diferentes biosensores enzimaticos con una optima conversion electrocatalitica, y cuya sensibilidad puede ser facilmente controlada mediante el numero de capas depositadas. La aplicabilidad de las estructuras supramoleculares desarrolladas se demuestra con la construccion de un sistema bioelectrocatalitico basado en la Fructosa Deshidrogenasa asi como de un sistema bienzimatico compuesto por una Alcohol Oxidasa y una Peroxidasa, ofreciendo este ultimo una gran permeabilidad para el peroxido de hidrogeno generado. Las estructuras desarrolladas se han caracte...

Antioxidants, 2021

There are several methods for quantifying malondialdehyde (MDA), an oxidative stress biomarker, i... more There are several methods for quantifying malondialdehyde (MDA), an oxidative stress biomarker, in exhaled breath condensate (EBC). However, due to the very diluted nature of this biological matrix, a high variability is observed at low concentrations. We aimed to optimize a 2,4-dinitrophenylhydrazine-based method using liquid chromatography coupled to tandem mass spectrometry and characterize the uncertainty associated with this method. We investigated the following parameters for the method validation: calibration linearity, limit of detection (LOD), precision, recovery, and matrix effect. The results were used to identify the main sources of uncertainty and calculating the combined uncertainty. The applicability of this method was evaluated in an ongoing epidemiological study by analyzing 164 EBC samples collected from different professional groups in subway environments. The optimized method was sensitive (LOD: 70 pg/mL), precise (inter-day variation < 19%) and accurate (reco...

Journal of Nanoparticle Research, 2020

Photocatalytic cement is self-cleaning due to the addition of titanium dioxide (TiO2) nanoparticl... more Photocatalytic cement is self-cleaning due to the addition of titanium dioxide (TiO2) nanoparticles, which react with sunlight (UV) and produce reactive oxygen species (ROS). Construction workers using photocatalytic cement are exposed not only to cement particles that are irritants but also to nano TiO2 and UV, both carcinogens, as well as the generated ROS. Quantifying ROS generated from added nano TiO2 in photocatalytic cement is necessary to efficiently assess combined health risks. We designed and built an experimental setup to generate, under controlled environmental conditions (i.e., temperature, relative humidity, UV irradiance), both regular and photocatalytic cement aerosols. In addition, cement working activities—namely bag emptying and concrete cutting—were simulated in an exposure chamber while continuously measuring particle size distribution/concentration with a scanning mobility particle sizer (SMPS). ROS production was measured with a newly developed photonic sensin...

BMJ Global Health, 2020

IntroductionDuring pandemics, such as the SARS-CoV-2, filtering facepiece respirators plays an es... more IntroductionDuring pandemics, such as the SARS-CoV-2, filtering facepiece respirators plays an essential role in protecting healthcare personnel. The recycling of respirators is possible in case of critical shortage, but it raises the question of the effectiveness of decontamination as well as the performance of the reused respirators.MethodDisposable respirators were subjected to ultraviolet germicidal irradiation (UVGI) treatment at single or successive doses of 60 mJ/cm2 after a short drying cycle (30 min, 70°C). The germicidal efficacy of this treatment was tested by spiking respirators with two staphylococcal bacteriophages (vB_HSa_2002 and P66 phages). The respirator performance was investigated by the following parameters: particle penetration (NaCl aerosol, 10–300 nm), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry and mechanical tensile tests.ResultsNo viable phage particles were recovered from any of th...

Water, 2021

Eco-friendly showers aim to lower energy and water consumption by generating smaller water drople... more Eco-friendly showers aim to lower energy and water consumption by generating smaller water droplets than those produced by traditional systems. To evaluate the risk of users inhaling the contaminants associated with such water droplets—namely, chemical components or opportunistic bacterial pathogens such as Legionella—we modeled the behavior of water droplets aerosolized by water-atomization technology at a flow rate of 2.2 L/min and compared the results obtained using this model with those determined experimentally in a typical shower stall. Additionally, we monitored the number and mass of inhalable water droplets emitted by twelve showerheads—eight using water-atomization technology and four using continuous-flow technology—which have distinct characteristics in terms of water flow rate, water pressure, spray angle, and number of and diameter of nozzles. The water-atomizing showers tested not only had lower flow rates, but also larger spray angles, less nozzles, and larger nozzle...

Environment International, 2021

BACKGROUND Air pollution in subway environments is a growing concern as it often exceeds WHO reco... more BACKGROUND Air pollution in subway environments is a growing concern as it often exceeds WHO recommendations for indoor air quality. Ultrafine particles (UFP), for which there is still no regulation nor a standardized exposure monitoring method, are the strongest contributor to this pollution when the number concentration is used as exposure metric. OBJECTIVES We aimed to assess the real-time UFP number concentration in the personal breathing zone (PBZ) of three types of underground Parisian subway professionals and analyze it using a novel Bayesian spline approach. Consecutively, we investigated the effect of job, week day, subway station, worker location, and some further events on UFP number concentrations. METHODS The data collection procedure originated from a longitudinal study and lasted for a total duration of 6 weeks (from October 7 to November 15, 2019, i.e. two weeks per type of subway professionals). Time-series were built from the real-time particle number concentration (PNC) measured in the PBZ of professionals during their work-shifts. Complementarily, contextual information expressed as Station, Environment, and Event variables were extracted from activity logbooks completed for every work-shift. A Bayesian spline approach was applied to model the PNC within a Bayesian framework as a function of the mentioned contextual information. RESULTS Overall, the Bayesian spline method suited a real-time personal PNC data modeling approach. The model enabled estimating the differences in UFP exposure between subway professionals, stations, and various locations. Our results suggest a higher PNC closer to the subway tracks, with the highest PNC on subway station platforms. Studied event and week day variables had a lesser influence. CONCLUSION It was shown that the Bayesian spline method is suitable to investigate individual exposure to UFP in underground subway settings. This method is informative for better documenting the magnitude and variability of UFP exposure, and for understanding the determinants in view of further regulation and control of this exposure.

Journal of Hazardous Materials, 2020

Although, photocatalytic cement contains nanosized TiO2, a possibly carcinogen, no exposure asses... more Although, photocatalytic cement contains nanosized TiO2, a possibly carcinogen, no exposure assessments exist for construction workers. We characterized airborne nanoparticle exposures during construction activities simulated in an exposure chamber. We collected some construction site samples for regular cement in Switzerland and Thailand for comparison. Airborne nanoparticles were characterized using scanning mobility particle sizer (SMPS), portable aerosol spectrometer (PAS), diffusion size classifier (DiSCmini), transmission electron microscopy (TEM), scanning electron microscope energy dispersive X-ray spectroscopy (SEM-EDX), and X-ray diffraction. Bagged photocatalytic cement had 2.0 wt% (GSD±0.55) TiO2, while TiO2 in aerosols reached 16.5 wt% (GSD±1.72) during bag emptying and 9.7 wt% (GSD±1.36) after sweeping. The airborne photocatalytic cement particles were far smaller (approximately 50 nm) compared to regular cement. Cutting blocks made from photocatalytic cement or concrete, resulted in similar amounts of airborne nano TiO2 (2.0 wt% GSD±0.57) particles as in bagged material. Both photocatalytic and regular cement had a geometric mean diameter (GMD) < 3.5 µm. Main exposures for Thai workers were during sweeping and Swiss workers during drilling and polishing cement blocks. Targeted nanoparticle exposure assessments are needed as a significantly greater exposure to nano TiO2 were observed than what would have been predicted from the material's nano-TiO2 contents.

Journal of Breath Research, 2019

Exposure to environmental and occupational particulate matter (PM) induces health effects on the ... more Exposure to environmental and occupational particulate matter (PM) induces health effects on the cardio-pulmonary system. In addition, associations between exposure to PM and metabolic syndromes like diabetes mellitus or obesity are now emerging in the literature. Collection of exhaled breath condensate (EBC) is an appealing non-invasive technique to sample pulmonary fluids. This hypothesis-generating study aims to (1) validate an ion chromatography method allowing the robust determination of different metabolism-related molecules (lactate, formate, acetate, propionate, butyrate, pyruvate, nitrite, nitrate) in EBC; (2) apply this method to EBC samples collected from workers exposed to quartz (a known inflammatory particle), to soapstone (a less inflammatory particle than quartz), as well as to controls. A multi-compound standard solution was used to determine the linearity range, detection limit, repeatability and bias from spiked EBC. The biological samples were injected without fu...