Anisotropic composite polymer for high magnetic force in microfluidic systems

International audienceAnisotropic carbonyl iron-PolyDiMethylSiloxane (PDMS) composites were developed and implemented in microfluidic devices to serve as magnetic flux concentrators. These original materials provide technological solutions for heterogeneous integration with PDMS. Besides microfabrication advantages, they offer interesting modular magnetic properties. Applying an external magnetic field during the PDMS reticulation leads to the formation of 1D-agglomerates of magnetic particles, organized in the non-magnetic polymer matrix. This induces an increase of susceptibility as compared to composites with randomly dispersed particles. In this report, we explored the gain in reachable magnetophoretic forces in operating microfluidic devices, from the study of magnetic micro-beads motion injected in the microchannel. We show that even at relatively large distances from the magnetically-functionalized channel wall, the anisotropic composite leads to a factor two increase in the magnetophoretic force. Finally, further investigations based on finite element description suggest that the measured benefit of anisotropic composite polymers does not only rely on the global susceptibility increase but also on the local magnetic field gradients originating from the microstructure

Impedimetric biosensor based on electrospun PEI/PVA decorated with gold nanoparticles for glucose detection.

International audienceImpedimetric biosensor based on electrospun PEI/PVA decorated with gold nanoparticles for glucose detection

NMR implantable probe: limit of metabolites detection

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NMR planar microcoil for microanalysis

This article deals with the analysis of small sample volume by using a planar microcoil and a micromachined cavity. This microcoil is used as a nuclear magnetic resonance (NMR) radio frequency detection coil in order to perform in vitro NMR analysis of the sample introduced into the microcavity. It is a real challenging task to develop microsystem for NMR spectrum extraction for smaller and smaller sample volume. Moreover, it is advantageous that these microsystems could be integrated in a Micro Total Analysing System ($\mu$-TAS) as an analysing tool. In this paper, NMR theory, description, fabrication process and electrical characterization of planar microcoils receiver are described. Results obtained on NMR microspectroscopy experiments have been performed on water and ethanol, using a 1 mm diameter planar coil. This microcoil is tuned and matched at 85.13 MHz which is the Larmor frequency of proton in a 2 T magnetic field

Impedimetric biosensor based on electrospun PEI/PVA decorated with gold nanoparticles for glucose detection.

International audienceImpedimetric biosensor based on electrospun PEI/PVA decorated with gold nanoparticles for glucose detection

Investigation of NMR limits of detection for implantable microcoil

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Anisotropic composite polymer for high magnetic force in microfluidic systems (vol 21, 170, 2017)

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ALL-organic electrostrictive polymer composites with low driving electrical voltages for micro-fluidic pump applications

International audienceThis paper focuses on the improvement of a relaxor ferroelectric terpolymer, i.e., poly (vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) [P(VDF-TrFE-CFE)], filled with a bis(2-ethylhexyl) phthalate (DEHP). The developed material gave rise to a significantly increased longitudinal electrostrictive strain, as well as an increased mechanical energy density under a relatively low electric field. These features were attributed to the considerably enhanced dielectric permittivity and a decreased Young modulus as a result of the introduction of only small DEHP plasticizer molecules. In addition, the plasticizer-filled terpolymer only exhibited a slight decrease of the dielectric breakdown strength, which was a great advantage with respect to the traditional polymer-based electrostrictive composites. More importantly, the approach proposed herein is promising for the future development and scale-up of new high-performance electrostrictive dielectrics under low applied electrical fields through modification simply by blending with a low-cost plasticizer. An experimental demonstration based on a flexible micro-fluidic application is described at the end of this paper, confirming the attractive characteristics of the proposed materials as well as the feasibility of integrating them as micro-actuators in small-scale devices