Among the TIPs department, my research interests cover the field of soft/wet microrobotics, at the intersection between fluidic microrobotics and flexible microrobotics:
- Flexible microrobotics deals with motion at small scales relying on passive or active deformation of polymers and glass. These developments enable the production of active and sensitive catheters towards the exploration of gastro-intestinal (20mm) and bronchial (2mm) tracts, or even at smaller scale in the ear-nose-throat or vascualr pathways.
- Keywords: tunable stiffness, active matter digital shaping, glass based compliant mechanisms, in situ strain measurement based on Bragg gratings
- Fluidic microrobotics aims at developing mechanical functions at small scales by taking advantage of the dominant surface tension effects below the millimeter: actuation, kinematic guiding, tunable focus lenses, self-cleaning surfaces, capillary micro-assembly and grippers, thermocapillary micromanipulation, hybrid micro-assembly. This field has now reached enough maturity to consider active control of capillary based micromachines, thanks to a wide variety of stimuli (temperature, pressure, light, electric and magntic fields).
A third activity is dedicated to:
- Nose-to-Brain drug delivery. This recent drug delivery pathway short circuits the blood-brain-barrier, and is therefore a promising solution to deliver drugs against neurological diseases (Parkinson, epilepsy, Almzheimer).
Ongoing and recents projects
ENDOSTAB – Catheter stabilization in bronchial endoscopy (2023-2027)
Funding source: Win4Doc project funded by the Région Wallonne (Win4Doc Grant n° 2310045), in collaboration with Lys Medical (startup company located in Belgium)
Lung cancer is the leading cause of cancer-related deaths worldwide, accounting for 28% of all cancer deaths. In the context of its screening, it is common for lung nodules (suspected cancer) to be located in peripheral areas that are difficult to access through endoscopy. The majority of these nodules are non-cancerous, so it is essential to perform a local biopsy to establish an accurate diagnosis. However, the lung resembles a labyrinth with sections narrowing at each division, making it challenging to access a specific peripheral area. Furthermore, the need for using flexible and miniaturized tools imposes certain limitations. Flexibility is necessary to avoid damaging tissues or harming the patient but can result in tool deformation before biopsy. Reduced size helps minimize the invasiveness of procedures but limits the technologies or performance of accessories used. Therefore, there is still significant room for innovation in these indications.
Drawing from the experience already gained by Lys Medical and its partners in the field (ULB, Femto-ST), this project proposes various innovative approaches that, when combined, will address the mentioned challenges.
Due to various factors (patient positioning, lung inflation during the operation, tool changes, etc.), a significant positioning discrepancy can occur between the area to be sampled and the area actually biopsied. The Endostab project aims to solve this issue with innovative, miniaturized solutions integrated with the various endoscopic accessories or tools currently in development or on the market. Tool stabilization will improve confidence in biopsy, facilitate interventions, save time, and reduce the risk of misdiagnosis.
An examination of technical solutions to stabilize tools with diameters ranging from 1mm to 2mm in bronchial tubes with diameters between 1mm and 10mm will identify one or more solutions for in-depth study. Technical solutions mentioned in the literature rely on mechanisms involving chambers or inflatable balloons, as well as deployable structures. More complex and advanced options, such as robots, are also possibilities for development. Robotic actuation depends on actuators, control, feedback loops, etc. Various solutions can be evaluated and tested under appropriate conditions (realistic phantoms or ex-vivo trials) to validate the achieved performance.
ULB FER grant (2023) – Nanoscribe laser
Funding source: ULB, Fonds d’encouragement à la Recherche (2023-2024)
Summary: Laser source for the Nanoscrobe Photonic GT
FNRS CDR T.XXXX.YY (Promotor Prof. Jonathan GOOLE) – Instrumented Nasal Cast for Nose–to–Brain Drug Delivery
Funding source: FNRS (2023-2025)
FNRS PDR T.XXXX.YY (E-space 40013908) – 3D–Printed Voxel–based Soft Actuators with Selective Actuation (Voxels)
Funding source: FNRS (2023-2027)
Candidate: to be appointed
Summary: This project aims at producing miniaturized soft robots with the following characteristics: soft structures made of active voxels, produced with digital manufacturing at the sub-millimetric scale (without molding nor assembly). The voxels are composed of stimuli-responsive hydrogels, exhibit 5 of the 6 degrees-of-freedom, and can be selectively actuated, by responding to well-defined wavelengths of light thanks to the embedding of plasmonic nanoparticles. An example of application could be the construction of active structures made of active voxels and supporting miniaturized cameras to explore endoscopic pathways. The project falls into 5 work packages: production of active hydrogel materials, identification of the printing parameters, identification of the materials model, optimization of the active voxels with numerical simulation fed with the materials model, and finally, a proof-of-concept of printing voxels at the tip of an optical fibre, carrying the ligh at the selective wavelength needed for selective actuation of the voxels.
Fonds Emile DEFAY 2021 – Modélisation de la physique des écoulements au sein du système lymphatique
Funding source: Fonds Emile DEFAY (2021)
Résumé: Le système lymphatique assure le transport de la lymphe, crucial pour la défense et l’’élimination des déchets du corps humain. Ce transport se fait grâce à un réseau de canaux lymphatiques, comprimés par des muscles , dotés de valves anti-retour et dont la petite taille complique la modélisation des écoulements qui y prennent place. Nos expériences microfluidiques modèles aideront à bâtir des modèles physiques, permettant la compréhension et la résolution de problèmes d’écoulement de la lymphe.
Postdoc FNRS (Semaphore 40001013) – Bioinspired Soft Textured and Active Channels: from lymphatic vascular systems to microfluidics
Funding source: FNRS (2020-2023)
Candidate: Dr Martin BRANDENBOURGER
Summary: Mimicking the lymphatic system, this project aims at developing a novel fluidic flow system, replacing rigid channels and pressure sources by soft (i.e. compliant) channels and distributed actuation. In this biological system, recent studies have shown that self-regulated contractions of soft channels and asymmetric protuberances, called leaflets, anchored along the channel control the transport of lymph through a living body in a very efficient and robust way. This mechanical process will first be studied in a model system, incorporating the 3D-printed key geometrical features of soft channels (protuberances shape and distribution) inspired by the lymphatic system. In a second phase, I will introduce active distributed deformations using reactive polymers blocks and active resins. During both steps, experiments will be backed-up by numerical simulations and predictive theoretical models. In a third phase, the key features identified in the aforementioned processes will be implemented in microscale engineering devices, manufactured with the micro-printing facilities available at the TiPs laboratory (ULB). These prototypes will enable flow control in soft microfluidic channels, generating unidirectional flow and pressure from local active polymer actuation thus replacing external pressure sources commonly used in pneumatic soft robots. This 3 years project will therefore bring a better understanding of lymph flow, and develop new flow controls in microfluidics and soft robotics. On the long term, thanks to the blooming bioprinting techniques, our results are likely to be transferred directly to the lymphatic vascular system, and to overcome current limitations of soft robots and microfluidic systems in terms of actuation, autonomy and cost.
COMPLEXURF: Laboratorium voor complexe oppervlakken en grensoppervlakken
Funding source: FWO (2020-2024)
Zoals Nobelprijswinnaar Wolfgang Pauli stelde: “God maakte het bulkmateriaal; oppervlakken werden uitgevonden door de duivel ”. Oppervlakken en grenslagen zijn gevoelig voor fysische en chemische modificaties als gevolg van interacties met ongecontroleerde atmosferen, reorganisatie van het oppervlak en verontreinigingen. Kwalitatief hoogwaardig onderzoek van interfaces kan daarom alleen worden uitgevoerd als oppervlakken op eenzelfde plaats kunnen worden voorbereid, behandeld en geanalyseerd. De KU Leuven is zeer actief op dit gebied. Dit wordt ondersteund door een verzameling van ultramoderne apparatuur die bijdraagt aan een beter begrip van de mechanismen die de interface-eigenschappen bepalen. Het ontbreekt ons echter nog aan hulpmiddelen om oppervlakken van materialen met verschillende vormen (vlakke monolieten, vezels, deeltjes) op relatief grote schaal (20×20 cm²), snel en nauwkeurig te behandelen en te karakteriseren. Dit is de ontbrekende schakel tussen fundamentele studies en toegepaste onderzoeken waarbij schaaleffect, herhaalbaarheid, snelheid van metingen, veelzijdigheid met behoud van nauwkeurigheid een belangrijke rol spelen. Dit project heeft tot doel een laboratorium op te zetten dat zich toelegt op de studie van complexe oppervlakken en interfaces en wordt ondersteund door een groep wetenschappers en ingenieurs met complementaire kerncompetenties die zullen bijdragen tot het ontrafelen van complexe fysisch-chemische interface verschijnselen.
FNRS PDR T.0049.20 (Semaphore 35248376) – Instrumented flexible glass structure (INFuSE)
Funding source: FNRS (2020-2024)
Candidate: Loïc AMEZ-DROZ and Mateo TUNON DE LARA
Summary: This proposal combines two key ingredients towards the development of resonators for inertial sensors and sensor arrays with embedded photonics for force/strain and biochemical sensing. The first key is related to the outstanding properties of glass, among which low loss factor (excellent for resonators), low thermal expansion (excellent for precision mechanics), optical quality surface finish, optical properties excellent to measure deformation of flexures by photo-elasticity or Bragg gratings, high elastic limit to Young modulus ratio (very good for large range and high resolution force sensors). However shaping glass at the small scale (<1mm) is very challenging. This will be solved thanks to the second key, which is the FEMTOprint machine. This new equipment allows 3D printed micro-devices out of glass and other transparent materials with sub-micron resolution, enabling the integration of fluidic, optical and mechanical functionalities in single monoliths at nano- and micro-scale. The technique is based on a 2 steps process: direct laser writing, followed by a chemical wet etching. Typical applications include precision mechanics (flexure hinges, microfluidics, micromolding, and micro-optics (microlenses, diffractive optical elements, nanogratings, waveguide and lab-on-fiber, integrated optical monitoring and sensing, the latter one is our target). This equipment would enrich our experimental platform micromilli.ulb.be and complement the Nanoscribe Photonic GT platform avaible for micron scale structuration of polymeric structures.
ULB grant – INFuSE
Funding source: ULB (2019-2020)
ULB FER – Femtoprint
Funding source: ULB (2019-2020)
Summary: Etching cabinet and ultrasonic bath
FNRS CDR – SMP molding of smart catheters
Funding source: FNRS CDR 33662043 (2019-2020)
This project aims at studying the manufacturing of Shape Memory Polymers (SMPs) for smart structures smaller than 3mm, with applications in soft robotics and in the medical field. Today, polymers are the key materials used in soft robotics because of their high flexibility, low cost, light weight and ability to withstand large strains. In many applications, a flexible state is required for shape conformity and for safe human interactions, while a rigid state is necessary for accurate positioning and force transmission. Interestingly, SMPs exhibit a large change in elastic properties with the temperature. Indeed, their Young modulus value can drop up to three orders of magnitude around their transition temperature, making them promising candidates for controllable stiffness solutions. Furthermore, they present shape memory effect that could be applied to develop actuators and smart structures. These polymers can be 3D printed from filaments with classical Fused Deposition Modelling technique or molded from 2-parts resins. 3D printing the polymers would be improved by the use of a multimaterial printer for creating segmented structures with localized active parts. A planetary vacuum mixer would allow for molding the SMP with higher resolution than FDM 3D printing making possible the miniaturization of the solutions targeted in this project. After manufacturing SMP samples, their thermo-mechanical characterization will take place thanks to the available equipment for tensile and bending stiffness evaluation in function of the temperature and the manufacturing parameters. Based on the experimental data, an improved finite element model will be developed in COMSOL. Modelling the SMP in this software would help for designing further proofs of concept and for optimization on the design. Finally, functional structures will complete the current promising proofs of concept based on this smart material for controllable stiffness solutions applied to small scale catheters.
FRIA GRANT – Capillary gripping
Funding source: FNRS FRIA PhD grant 33929287, Adam CHAFAI (2018-2022)
This project will allow to master capillary gripping and handling of objects under both theorical and experimental aspects. This technology could overcome the technical limitations of existing handling systems (showing manipulation and centring issues for small devices and being hazardous for fragile surfaces). Points that have to be mastered to ensure a great understanding and stability in any process involving capillary gripping will be studied (as the drop generation on the tool or the design and manufacturing of appropriate prototypes thanks to high-end equipment). Moreover, numerical simulations will be built to describe and anticipate the dynamic behaviour of components handled by capillary forces. Many experimental campaigns will be possible thanks to the scientific equipment of the host laboratory. Those facilities will allow to run tests with real conditions of speeds, accelerations and complex movements of the handlers.
FRIA GRANT – Soft Actuators for minimal invasive surgery
Funding source: FNRS FRIA PhD grant 34320231, Gilles DECROLY (2018-2022)
Collaborations: Prof. Alain DELCHAMBRE (ULB)
Soft robotics opens many new opportunities, but the lack of adapted actuation methods makes difficult the rise of new applications. In the medical field of minimally invasive surgery (MIS), soft steerable devices (typically catheters) could enable reaching locations through tortuous trajectories in the human body, while minimizing the risk of damage on tissues. They could become an alternative to the commercially available cable actuated or magnetic steerable catheters, because of their softness, safety, ability achieve more complex movements, and low cost. This work aims at investigating the possibility to use the solutions of soft robotics to develop a miniaturized actuator (diameter lower than 3mm) meeting the specific MIS requirements. Among the main types of soft actuation solution adaptable for MIS (cable, fluidic, or smart materials actuation), fluidic actuation and the innovative use of swelling materials are especially interesting for their high energy density. To assess the potential of these two solutions, several scientific questions have been identified, relative to the modeling of the soft actuator, the identification of the key design parameters, the influence of the material, the potential for miniaturization, the mechanical programming of complex movements, and the manufacturing. Therefore, the project will be divided in three tasks: (1) preliminary work (literature review, test bench development and MIS requirements). (2) Study of the two solutions: (a) fluidic actuation and (b) swelling material (development of prototypes, numerical and empirical models). (3) Development and characterization of a steerable catheter and integration of the stiffness variation as proof of concept. This thesis will take place in the BEAMS department (ULB) under the supervision of prof. Alain Delchambre (BEAMS) and Pierre Lambert (TIPs). This environment will indeed provide the multidisciplinary expertise in terms of miniaturisation and MIS devices.
FNRS GEQ – Glass-Based Optomicromechatronics (FEMTOprint)
Funding source: FNRS GEQ U.G025.19F, sémaphore 32930248 (2019-2020)
Collaboration: Prof. Benoit SCHEID (ULB), Prof. Christophe COLLETTE (ULg), Prof. Christophe CAUCHETEUR (UMons)
This proposal combines two key ingredients towards the development of resonators for inertial sensors and sensor arrays with embedded photonics for force/strain and biochemical sensing. The first key is related to the outstanding properties of glass, among which low loss factor (excellent for resonators), low thermal expansion (excellent for precision mechanics), optical quality surface finish, optical properties excellent to measure deformation of flexures by photo-elasticity or Bragg gratings, high elastic limit to Young modulus ratio (very good for large range and high resolution force sensors). However shaping glass at the small scale (<1mm) is very challenging. This will be solved thanks to the second key, which is the FEMTOprint machine. This new equipment allows 3D printed micro-devices out of glass and other transparent materials with sub-micron resolution, enabling the integration of fluidic, optical and mechanical functionalities in single monoliths at nano- and micro-scale. The technique is based on a 2 steps process: direct laser writing, followed by a chemical wet etching. Typical applications include precision mechanics (flexure hinges, microfluidics, micromolding, and micro-optics (microlenses, diffractive optical elements, nanogratings, waveguide and lab-on-fiber, integrated optical monitoring and sensing, the latter one is our target). This equipment would enrich our experimental platform micromilli.ulb.be and complement the Nanoscribe Photonic GT platform avaible for micron scale structuration of polymeric structures.
FNRS PDR – Thermo-Magneto-Capillary Self-Assembly
Funding source: FNRS PDR T.0129.18, Sémaphore 31252084 (2018-2022)
Collaboration: Prof. Nicolas VANDEWALLE (ULg)
Spontaneous generation of order in systems made of numerous components, called self-assembly, is known to be ubiquitous in biology and chemistry at the molecular level. Self-assembly is also encountered across length scales (from μm to cm), offering opportunities to generate 2D and 3D elaborated structures with low cost and simplified manipulations. This scale is called the mesoscale, in between bottom-up and top-down forms of fabrication. Using capillary driven mesoscale self-assembly to create complex structures is a scientific challenge that we will address in this project, focusing in particular on particles trapped along a liquid-air interface (this reduces the viscous drag when compared with the bulk, and enables interfacial phenomena such as long range capillary interactions). Our groups at ULB and ULg have indeed developed complementary ways to manipulate particles along interfaces: (i) The group at ULB has developed a micromanipulation station to manipulate tiny objects along liquid interfaces thanks to the thermocapillary effect. (ii) The group at ULg générâtes magnetocapillary assemblies made of identical soft ferromagnetic particles that are suspended at water-air interface, and subjected to a uniform magnetic field generated by Helmholtz coils. This project aims to combine these magneto- and thermocapillary effects to create complex active structures floating at the water-air interface. Practically, we will study (1) how the thermocapillary effect can affect the magnetocapillary bond and impact magnetocapillary assemblies; (2) how the magnetic field can be used as a elastic restoring force to measure thermocapillary forces (nN-μN range); (3) how the thermocapillary flow can be used to correct selfassembled patterns by adding/removing particles individually; (4) how thermocapillary barriers can confine magnetocapillary swimmers; (5) how thermocapillary flow can be used to improve the swimming capability of magnetocapillary assemblies.
FNRS PDR – Bioinspired passive liquid dispensing strategy at the micrometer scale
Funding source: FNRS PDR 26037417(2016-2020)
Collaborations: Prof. Tristan GILET (ULg) and Prof. Philippe COMPERE (ULg)
In nature, capillary forces shape the microscopic realm. However their use in microengineering and microrobotics is currently limited by the lack of a robust handling strategy of the tiny volumes of liquid involved. Most insects rely on capillary forces for terrestrial locomotion. Some (incl. beetles) have hairy adhesive pads on their legs that provide fast and reversible attachment on almost any substrate. A femtoliter of liquid is passively dispensed to the tip of each hair, where it forms a bridge with the substrate and provides robust capillary adhesion. Liquid footprints are minimized when the pad detaches. This research project aims at understanding and mimicking the liquid management strategy of these hairy pads. Through a biomimetic approach, we will (1) identify a robust fluidic design for passive liquid dispensing at the micrometer scale, and (2) determine the optimal kinematics of pad detachment that minimizes liquid residuals on the substrate.
FRIA GRANT – STIFFNESS – Controllable stiffness mechanisms for endoscopic catheter
Funding source: FNRS FRIA PhD grants, Loïc BLANC (2015-2019)
Collaborations: Prof. Alain DELCHAMBRE (ULB)
This research project aims at studying controllable stiffness mechanisms for catheters to be used in endoscopy (diameter lower than 3mm). Some applications indeed require to alternate between a flexible state (e.g. to follow a path) and a rigid one (e.g. force transmission). Such variable stiffness is required for applications in robotics, in active control for mechatronics, in aerospace and in biomedical field. Among these applications, the case study chosen for this PhD project is related to catheters used in case of vascular occlusions, transbronchial biopsy or interventional gastroenterology. These case studies require to go beyond the available state of the art with specifications as miniaturisation (diameter lower than 3mm for insertion in the working channels of endo- and bronchoscopes) or bending curvature compatible with anatomic constraints. In order to obtain controllable stiffness, literature already mentioned different principles (use of polymers, granular or layer jamming systems, etc.) which still need to be quantitatively compared and whose limits must be carefully detailed with respect to the above mentioned requirements. Moreover, the questions to answer are to know stiffness order of magnitude and variation range, control stimuli and design rules. Therefore, the plan of work includes 4 steps: (1) Test bench development, (2) Experimental study of granular jamming mechanisms as it seems promising in terms of performances, applications and fundamental questions open to research (no clear design rules available yet to engineer such mechanisms), (3) Study of layer jamming systems for similar reasons, (4) Prototype of a catheter with controllable stiffness. Funded by the FNRS FRIA PhD grants (candidate: Loïc BLANC).
FNRS GEQ (22687275) – 3D microstructuration and microengineering of surfaces with 2 photon lithography
Funding source: FNRS GEQ (2014-2016)
Collaborations: Prof. Pierre COLINET (ULB), Prof. Benoit SCHEID (ULB), Prof. Tristan GILET (ULg), Prof. Joël DE CONINCK (UMons)
Related: Bio-inspired capillary adhesion (PhD, Sophie Gernay)
Among the research framework of the Belgian research network on microfluidics and micromanipulation (PAI 7/38 MicroMAST) – whose all French speaking partners (ULB, UMons, ULg) support this current application – we aim at studying two scientific domains. The first one is devoted to the study of capillary adhesion (and release) mechanisms developed by some hexapods (insects), and the second one is the study of the wetting dynamics on structured surfaces. Both domains are complementary and full of promising perspectives (as well applied as fundamental perspectives). Let us mention for instance the possible application of the capillary adhesion mechanism to the industrial pick and place of electronic components smaller than 100μm. More fundamentally, an exciting perspective of this project would be to unify the current hydrodynamic and molecular theories describing wetting dynamics, especially on textured surfaces. To study these questions experimentally and pioneer beyond the state of the art, it would be necessary to control manufacturing of microstructures below the micron scale, which indeed drives the wetting and adhesion underlying mechanisms. The equipment targeted in this application is the micro/nanomanufacturing station developed by the Nanoscribe company. This equipment is based on 2 photon photo-polymerisation of proprietary resins (resolution of about 0.3μm). It has been demonstrated to produce various microstructures including periodic pattern, controlled disorder, porous structures as well as large aspect ratio geometries observed in the complex geometries of insect legs extremities.
IAP 7/38 MicroMAST – Microfluidics and Micromanipulation: Multiscale Applications of Surface Tension
Funding source: BELSPO (2012-2017)
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The scientific objectives of this network are driven by fundamental questions raised in microfluidics, interfacial science, and micromanipulation. The rational use of surface tension, surface stress and capillary effects in micromanipulation will be applied to a selected number of highly relevant case studies by the network partners, including capillary gripping, capillary filling, capillary alignment, capillary sealing, capillary self-assembly and droplet manipulation.
These fundamental questions can be grouped into three categories:
- Fluid statics and dynamics: How much force is applied on solids by menisci and micro-flows in a given geometry? What happens if the solid bends when subject to these forces? Are the interfaces stable and what if not? What is the effect of an electric field? How can the microscopic description of wetting be translated into an adequate boundary condition at the macroscopic level?
- Surface engineering: How does a contact line move on a rough surface? Can one pattern the surface microscopically to control this motion? How is the motion affected by evaporation, or by the presence of colloid particles in the liquid or at the interface? Do these particles interact with the micro-patterns on the surface? Can one create highly 3D patterns on the surface by using capillary forces?
- Liquid engineering: How to measure the interfacial properties of complex liquids where apart from surface tension a surface viscoelastic response is present? How to infer macroscopic properties from the dynamics at the molecular scale? And how to engineer liquids and tailor them to the requirements arising from applications? Can one make a liquid that is biocompatible, and has a large surface tension and a low viscosity?
The proposed program is highly multidisciplinary, as it combines the forefront research in physics, material science, chemistry and engineering. It will cover topics that range from fundamental theory with atomistic simulations to experiments to investigate the fundamentals and selected more applied case studies. It will address both static and dynamic points of view, and establish the link between the microscopic properties of liquids and surfaces, and the macroscopic performances expected in the case studies. To that aim, this IAP project has gathered a multi-disciplinary research team that covers all the disciplines listed above.
The originality of this network relies in the efforts to enhance the collaboration of both the interfacial science, microfluidics and microengineering communities.
ARC – PREDICTION – PRotein dEtection for in vivo DIagnosis using CaTheterlc Optical fibre bioseNsors
Funding source: ARC (2012-2017)
Highly multidisciplinary, this project involves groups of ULB and UMons : Department of Gastroenterology, Hepato-pancreatology and Digestive Oncology – Jacques Devière (Faculté de Médecine, ULB), Bio-, Electro- and Mechanical Systems Department – Pierre Lambert (BEAMS, Ecole Polytechnique de Bruxelles, ULB), Service d’Electromagnétisme et de Télécommunications (SET, UMons) and Service de Protéomique et Microbiologie (ProtMic, UMons).
Related: Design of smart catheter for cancer cells detection in the lungs (PhD, Jean-Charles Larrieu)
Optical fiber biosensors can perform sensitive and quantitative measurements of the presence and concentration of biomolecules such as proteins or DNA. They can therefore contribute to major advances in medical diagnosis, food quality control, drug development and environmental monitoring. Additionally they offer the prospect of being used for in vivo detection, which would considerably improve the rapidity and reliability of a diagnosis. The key point of such biosensors is the joint development of the sensing platform, the biochemistry around and the protective packaging. The sensing platform comprises the development of the optical fiber sensors and their interrogation while the biochemistry mainly consists in coating the fiber with bioreceptors that will enable to detect ligands through the antibody/antigen affinity. An innovative protective packaging will be developed for the proposed application.
FNRS PDR – Micro-Macro study of the capillarity effects on mechanical behaviour of granular materials
Funding source: FNRS PDR (2014-2018)
Collaborations: Prof. Bertrand François (Promotor), Prof. Pierre Gérard, Prof. T.J. Massart
When the pore space of granular materials is filled by more than one fluid phase, liquid bridges including capillary meniscus link particles together. In the conventional geomechanical approaches, suction is used as the stress variable that controls the mechanical effects linked to the partial saturation of the voids, not considering explicitely the role of the capillary forces. The objective of this project is to quantify the combined effects of suction and capillary forces on mechanical behaviour of granular materials from joined microscopic (at the scale of the meniscus between two grains) and macroscopic (at the scale of an assembly of hundreds of grains) approaches. At microscale, the capillary forces will be evaluated experimentally and corroborated with numerical models based on the geometry of meniscus and surface tensions of the fluids. At macroscale, experimental tests will be developed to follow the compressibility as well as shear strength of granular materials under partial water saturation. The computational development carried out at the small scale will be extended to a larger scale by taking into account the tri-dimensional grain organisations through a granular microstructure generator tool previously developed by one of the promotors. The water retention curve will be used as the macroscopic properties controlling the mechanical response of the material. A computational homogenisation technique will manage the transition between micro- and macro-scales that will allow to perform numerical prediction of geomechanical structural problem (such as slope stability problem). This project encompasses various expertises in a unified research framework: the physics of capillarity, the experimental geomechanics of unsaturated geomaterial and the computational mechanics of porous media.
RW Beware Academia – MULTISCO
Funding source: Région wallonne, BEWARE Academia (2014-2018)
Collaborations: Prof. Jean-Marie RAQUEZ (Promotor, UMons), Endo tools Therapeutics S.A.
Les matériaux polymères à mémoire de forme (PMFs) trouvent de nombreuses applications dans le domaine biomédical comme fils de suture « intelligents » et cathéters auto-répondants pour applications cardiovasculaires complexes. La plupart des PMFs sont généralement actionnés via une différence de température, combinant un domaine permanent (structure chimiquement ou physiquement réticulée) et un domaine d’actionnement associée à une température de transition (température de transition vitreuse ou de fusion). Leur efficacité dépend de la structure chimique du polymère, du degré de réticulation et de la fraction massique entre les domaines amorphes et cristallins. L’énergie qui est restaurée lors de l’actionnement (changements de forme) est fonction de celle stockée au cours de la programmation. Malheureusement, par rapport aux autres technologies d’actionneurs, la déformation est généralement associée à une faible reprise de la rigidité des matériaux. L’inclusion de nanoparticules telles que des nanotubes de carbone pour leur conductivité électrique a récemment permis d’améliorer les propriétés mécaniques des matériaux polymères à mémoire de forme. L’objectif de ce programme de recherche sera donc de développer des nanocomposites polymères à mémoire de forme à actionnements multiples en termes de nombre de changements de forme à adopter (induits suite à un stimulus thermique), d’amplitude de la réponse et de rigidité pour des applications endoscopiques. En collaboration avec le BEAMS-ULB et la PME Endotools, de tels dispositifs seront, en effet, évaluées dans l’optique d’interventions endoscopiques en développant des aiguilles endoscopiques, alliant ses différentes fonctionnalités techniques lors de l’opération chirurgicale afin de minimiser le nombre d’actes chirurgicales et donc le traumatisme post-opératoire.