The LabPsi project aims at demonstrating that lateral porous silicon membranes integrated into planar microchannels (as opposed to classical porous silicon membranes integrated in 3D fluidics) constitute a single nanotechnological brick to carry out all steps required for the detection of biomolecules in crude samples on-chip: sample preparation (sample filtration and sample enrichment via ion concentration polarization) and biosensing (via interference spectroscopy). This approach provides a promising solution for future diagnostic devices, where monolithic processes could replace current hybrid fabrication methods. Outcomes of this project in the field of nanostructured materials for health care are expected at various levels: increase in fabrication reliability, solutions for material integration and adequate functionalization strategies. As a proof-of-concept, we plan to fabricate a lab-on-a-chip for the detection of Troponin I in blood for myocardial infarction diagnosis.

Many physical and engineering systems are modeled mathematically by the dynamic equations, and the static relations describing constraints on evolution of trajectories. Interconnections of such constrained dynamical systems are observed in many practical applications and control of such systems is, not only of theoretical interest, but also has many advantages. This project proposes the study of control of interconnections of constrained dynamical systems using the mathematical tools from set-valued and variational analysis, with applications such as contact mechanics, traffic networks, and robust control of network of agents. The interesting feature of the constrained systems treated in this project arises from the nonsmooth behavior in the system description, and the trajectories. The mathematical models used for describing the constrained systems form a particular class of time-varying differential inclusions where the set-valued mapping may switch from zero (in the interior of the constraint set), to a cone (at the boundary of the constraint set). Such discontinuities in the vector field, and consequently in the state trajectory, require sophisticated mathematical tools for studying solution properties. When considering interconnections of such systems, which is the topic to be studied within the scope of ConVan, one has to take extreme care with regards to feasibility of such connections. Developing appropriate mathematical models and establishing solution properties for these interconnections is our first main goal. The second goal of this proposal is to carry out rigorous stability analysis for the interconnected constrained systems. Using a connection of two constrained systems as a template (which has its own significance in many control design problems), we aim to develop appropriate stability notions. This will be followed by investigating the use of nonsmooth Lyapunov functions to obtain constructive stability conditions. Once concrete analytical results are obtained for stability, we wish to use them for certain design problems with control inputs. Finally, we aim to use these results in network related applications where either the trajectories of individual subsystems are constrained, or new constraints appear due to interconnections. By working on these research problems, the coordinator aims to study appropriate mathematical models for interconnections of constrained systems, develop tools for stability analysis and control design for systems, and investigate network related applications. This way, ConVan aims to contribute towards development of fundamental research for numerics and control of constrained interconnected systems.

The goal of this project consists in developing a portable and sensitive platform dedicated to the detection of the water pollution for fast diagnoses. The project will be concentrated on the following aspects : detection and analyze of several analytes on only one platform, and miniaturization to carry out the analysis on site. To achieve this goal, a integrated chip made up of electrochemical microsystem (electrochemical microcell with three electrodes) and optic microsystem (organic electroluminescent diodes OLEDs and photodiodes) is proposed. In order to increase the sensitivity and the selectivity of the system, the detection will be based on the use of a biosensor made up of algae or cyanobacteries. The algae are natural biosensors, because they integrate the biological effects of their environment and answer by metabolic changes which are representative of the potential toxic effects. Thus, the measurement of the answer of the algae in real time thanks to microsensors which can be optical, chemical or electrochemical would thus make it possible to detect the presence of possible pollutants. The microfluidic circuit realized with polymer materials and composed of several cells of analysis will allow detection in parallel of different pollutants. OLEDs will be integrated into the substrate and associated with the tanks used for detection, the photodiodes and the electrochemical cells as for them will be integrated in the upper part of the microsystem. The purpose of each optimized OLED, coupled with filters, will be to initiate a different fluorescence reaction according to the alga to be studied, each one requiring an emission with a wavelength given according to its specificity. After the absorption, the reception of the light output of the algae, as for it, will be carried out by the optimized OPD. The electrochemical cells will be made up of three integrated electrodes systems (Ag/AgCl/Cl- reference electrode, Pt counter-electrode and working electrode (Au, Pt, IrO2, WO3, ...) according to the element to detect: dissolved oxygen, pH, peroxide or others molecules of interest) in the higher cap of the microfluidic structure. The signals will be then treated by network of neurons for analysis and will be compared between them. This project constitutes a multi-field approach calling upon chemistry, physics, biology, microsystems engineering with an aim of providing a complete and miniaturized microsystem for the detection of pollutants. The multi-detection system using several different species of algae or cyanobacteries provides on the one hand, the increasing of the reliability of the test on the qualitative point of view by increasing the list of the detected pollutants, and on the other hand, to obtain a selective test concerning the class of pollutants in the water. In fact, each kind of algae has its own morphology and physiology and thus, its sensibilty to pollutant is different to an other algae sensibility. A complete analysis of the pollutants will be done later in specific laboratory : it will reduce significantly the cost of the water analysis because only toxic samples should be analysed completely by specific laboratories.

Controlling the placement of molecules on large surfaces with nanometer precision is a common goal of photonic, electronic and biosensing. Top-down fabrication (through lithography, deposition and etching) has been a very successful technology to shape matter from the centimeter down to the 100-nm range. Yet, as the technology is pushed further down, it becomes prohibitively expensive to overcome the limitation of diffraction and reach for the 1-100 nm range. Bottom-up assembly is a perfect technology to bridge this gap. Inspired by the robustness and precision of self-assembled biological structures, bottom-up assembly relies on the programmed self-assembly of atoms and molecules to build large complexes (10-100nm) from simple bricks (0.1-1nm). Top-down and bottom-up assembly hold together the potential to tailor the properties of materials down to the atomic scales, thus enabling tremendous new applications. I propose to combine bottom-up and top-down assembly, coupled to single-molecule microscopy and microfluidics, in order to address technological locks in the quantification of biomolecules. By arranging biomolecules with nanometer precision on square millimeter surfaces, we aim to build digital arrays that count digitally many distinct targets, with high sensitivity, high specificity, minimal operations and high reliability. Because the array will be developed with potential applications in mind, a particular emphasis will be placed on robustness, reproducibility and integration.

The project deals with the integration in the field of power electronics. It aims at developing new quasi-monolithic or monolithically integrated silicon power switching cells of higher performance and reliability. More precisely, The project aims to demonstrate through technological realisations two new integration approaches of inverter bridge legs in order to reduce the number of discrete silicon chips in a power module making it possible to reduce or suppress wire-bondings as well parasitic coupling capacitances. That will lead to performance as well as reliability improvement. The strategies that we propose for improving the performance and reliability of power modules are new in the sense that they combine both the monolithic and hybrid integration approaches for the optimisation of the entire system. Indeed, generally the followed optimisation approaches focus either on the silicon chip or on the packaging. Interconnection technologies were developed for wire-bonding reduction. However, the technology of realisation is generally very complex. For low power applications (few hundreds of Watts), the monolithic integration of power conversion functions and their driving circuitry can be carried-out through the use of lateral power devices. This integration approach is unfortunately restricted to some applications such as : household appliances and auxiliary power functions. It has however the advantage of allowing wire bonding reduction and it allows a collective fabrication of the power function. For medium power applications (few kW to few 10 kW), the use of vertical power devices is necessary. The vertical devices extend from the upper side of the silicon wafer down to the lower side. When many vertical power devices share the same silicon chip, their drift regions (lightly doped) are not electrically isolated from each other. In this project, a technique based on the use of vertical boron highly walls will be developed. To that end, we have recently started research works on the design and realisation of new multi-switch silicon chips. The integrated switches have a vertical architecture. We intend to set up new solutions that will permit the realisation of power switching cells by assembling the minimum number of power silicon chips as compared to the classical approach. We first target to design and realise new complementary multi-switch silicon chips : common anode and common cathode multi-switch cells. Then we merge the two complementary multi-switch chips in order to devise and realise a monolithic macro-chip of a particular architecture. The complementary power silicon chips as well as the compact packaging will be optimised simultaneously in a system optimisation approach that targets generic applications and laboratory prototypes. The single macro-chip integration approach is the most ambitious approach due to the technological challenges for its realisation. However, if the fixed objective of realising the macro mono-chip is reached, this structure will be for us the ultimate integration and will be very attractive from the applications point of view.