Manufacturing of analytical microsystems by thermoplastics micro-milling
Micro-fabrication techniques and especially micro-milling can be used to manufacture microsystem prototypes with a timescale of days, as close as possible to the application. Polymethylmethacrylate (PMMA - Commercial name Plexiglas) is a commonly used material for microsystems fabrication, limited however by its chemical incompatibility with acids and solvents.
The goal of this post-doctoral project is to study the feasibility of machining thermoplastic materials other than PMMA and to optimise the associated manufacturing parameters. The post-doctoral project will start with the selection of materials in line with the aimed applications (optical and physico-chemical properties). The materials will be selected among the thermoplastics family (PC, POM, PS, HDPE, PEEK, PVC, PP, PTFE, ULTEM, etc).
The optimisation of the micro-milling step will be realized by varying parameters such as the tool rotation speed, the feed rates, the depth of cut, etc. The surfaces and channels will be characterized by optical or mechanical profilometry, optical microscopy and/or scanning electron microscopy.
Detection of traces of narcotics in saliva by electrochemiluminescence on diamond electrodes
The consumption of narcotics is becoming a problem for road safety because 23% of road deaths in France occur in an accident involving at least one driver who tested positive. Thus, one objective of road safety in consultation with the concerned ministries (Ministry of Transport, Ministry of Interior, Ministry of Health and Ministry of Economy) is to improve the fight against road insecurity linked to narcotics consumption. In particular, this involves increasing and facilitating roadside checks using a portable device dedicated to controlling the use of narcotics on the roadside, similar to what is already done for breathalyzer tests. Such a device is not commercially available today. The main prerequisites of this device will be to provide reliable, immediate confirmation results with evidentiary value for the courts as well as a purchase cost compatible with large-scale deployment on French road networks. In this context, the subject of study proposed aims to study the possible detection of traces of narcotics in saliva using electroluminescence on a boron-doped diamond electrode. This method is considered promising for such an application because it potentially allows extremely low detection thresholds to be reached and, in accordance with legislative requirements, offers multiple possibilities aimed at achieving high selectivity towards chemical targets, with a high detection capacity. miniaturization of equipment and a relatively low cost of apparatus compared to analytical tools such as mass spectrometer, IMS, etc.
Separation microsystem coupled to mass spectrometry for on-line purification and characterisation of nuclear samples
The miniaturisation of analytical steps commonly carried out in laboratories offers many advantages and particularly in the nuclear sector, where the reduction of material consumption and waste production is of major interest. In this context, one of our laboratory’s focus area is the miniaturisation of analytical tools, particularly chromatographic separation techniques. The aim of this project is to reduce the scale of the purification steps of nuclear samples by solid phase extraction chromatography, prior to the analytical processes. Obtaining these miniaturised extraction devices is based on the in situ synthesis and anchoring of monoliths, in the channels of cyclic olefin copolymer (COC) microsystems. Since this material is chemically inert, COC functionalisation strategies are currently under development to covalently graft reactive sites on its surface, before locally anchoring actinide-specific monoliths in the micro-channels. The aim is to design and fabricate chromatographic extraction microsystems in COC, and to implement them for chemical purification and mass spectrometry measurements, both off-line and on-line.
Leaching foams to extract metals from electronic waste
The subject is part of the ANR "Foamex" project covering TRL from 1 to 5 and focussing on the development of recycling of some metals from a shred of electronic cards, this recycling being carried out in a fluid foam (minimization of the volume of solvents) that can be considered at the first level as a dynamic chromatography column. The principle is to use the foam as a reservoir containing an acid solution and specific oxidizing agents to dissolve and extract metals in the form of ionic species, a phenomenon enhanced by friction between bubbles and simultaneously to concentrate them via the fluid and mobile liquid/air interfaces by flow.
Development of methods for U quantification in cells after exposure to uranium
This project fits into the transverse Toxicology Program, led by CEA, whose purpose is to address by multidisciplinary approaches, the potential effects on living organisms of elements of strategic interest to the CEA. The objective is to provide some understanding on the mechanisms of uranium toxicity and behavior, in connection with its speciation in cells. Indeed, the radionuclides speciation governs their bioavailability, accumulation, biodistribution, toxicity, detoxification mechanisms and their interaction at the molecular level.
The post-doctoral project (12 months) consists in:
- Developing methods to quantify U accumulated in the cells as well as endogenous content of trace elements after exposure of cells to uranium.
- Developing methods to determine the precise isotopic composition of U in the cells after their exposure.
The candidate will be in charge of developing chemical purification and measurement methods for precise elemental and isotopic analyses. The analyses will be performed using inductively coupled plasma quadrupole mass spectrometer (ICP- MS Q) or inductively coupled plasma multi- collection mass spectrometer of the latest generation (ICP- MS MC), to achieve the lowest level of uncertainties.
Gas sensors based on diamond nanoparticles and nanoporous materials
The aim is to develop surface acoustic wave sensors (SAW) with high sensitivity and high selectivity to gaseous compounds (< 100 ppb). The development strategy involves the use of diamond nanoparticles based guiding layers deposited on the piezoelectric substrate and chemically modified to tune the specificity of the sensors. In order to increase further the selectivity, the sensors will be coupled to specific filters placed before the sensors and based on probe molecules trapped in porous sol-gel based materials and able to react non-reversibly with interferent molecules. The topic includes 4 mains sections: 1) synthesis and functionalisation of diamond nanoparticles, 2) study of probe molecules and immobilisation in porous matrices, 3) study of the filtering capacity of the filters toward relevant interferent species, 4) metrology and calibration of the sensors. This work will be carried out in the "Diamond Sensors Laboratory" as well as laboratoire Francis Perrin both located in CEA Saclay.