Publications by Philippe Renaud

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This paper reports the new combination of cell sorting and counting capabilities on a single device. Most state-of-the-art devices combining these technologies use optical techniques requiring complicated experimental setups and labeled samples. The use of ...

We present a fully integrated Mach-Zehnder interferometer in silicon-on- insulator technology. Modulation of the index of refraction is achieved through the plasma dispersion effect resulting in a bandwidth in the 10 MHz range. A particular and innovative design makes this device completely compatible with CMOS technology allowing electronic functions to be integrated on the same substrate. Measurement results, limitations due to thermooptic effect and absorption related to charge injection together with fu

his paper reports on an electrical lysis device with integrated cell counting and evaluation of the lysis efficiency by multiplefrequency impedance measurements. Conventional techniques use chemical reagents to lyse cells, causing unwanted interference wit ...

We present a compact portable biosensor to measure arsenic As(III) concentrations in water using Escherichia coli bioreporter cells. Escherichia coli expresses green fluorescent protein in a linearly dependent manner as a function of the arsenic concentrat ...

The use of neural implants for stimulation and recording show excellent promise in restoring certain functions to the central nervous system; and neuroprostheses remains one of the most important tools of neuroscientists for the elucidation of the brain's function. Ailments such as Parkinson's disease, obesity, blindness, and epilepsy are being studied from this angle. Development of better electrodes for recording and stimulation is therefore critical to ensure continuing progress in this field. This book

This work presents label-free separation of cells in an on-chip flow cytometer based on impedance spectroscopy. The amplitude, opacity, and phase information can be used for discrimination depending on the cell types. Red blood cells, ghosts, and fixed cells are differentiated based on differences in their membrane and cytoplasm dielectric properties. Among other applications, detecting changes in cell conductivity and membrane capacitance will allow the indentification of early-stage apoptosis or cancer.

The increasing interests in micro-electro-mechanical systems (MEMS) has raised the requirement for photoresist materials with improved friction and wear properties for mechanically loaded 3D shaped microstructures. In this work, SU8 photoresist layers rein ...

This paper describes new polymer/ceramic photosensitive resins that can be used in the microstereolithography process for manufacturing complex 3D components in composite material. These new resins contain high loads (up to 80 wt.%) of alumina nanoparticles, used as fillers in a photosensitive acrylate-based resin of low viscosity. With the nanopowder-filled resin we developed, various small polymer/alumina composite components having a real geometric complexity were produced with small manufacturing times.

Electroporation is defined as cell membrane permeabilization under the application of electric fields. The mechanism of hydrophilic pore formation is not yet well understood. When cells are exposed to electric fields, electrical stresses act on their surfa ...

Cell-imprinting technology is a novel method for directing stem cell fate using substrates molded from target cells. Here, we fabricated and studied cell-imprinted substrates for neural priming in human adipose-derived stem cells in the absence of chemical ...

Variations in calcium ion (Ca2+) concentrations play a crucial role in cell-cell communication; periodic changes act as cellular signals. In this study, we developed a solid-state calcium ion-selective electrode (Ca2+ ISE) integrated in a microchannel to measure extracellular Ca2+ variations; an ISE has a high detection sensitivity (as low as 10(-9) M) and selectivity against potassium ions (K+). The sensor was used to monitor the cellular activities of HepG2/C3As cultured in a microchannel. We measured a p

Exposure of a bacterial culture to an antibiotic or other lethal stress typically results in the generation of sub-populations of live cells ("persisters") and dead cells, and, in some cases, viable but non-culturable cells. Studies aimed at understanding the mechanisms of antibiotic killing and bacterial persistence will require the purification and analysis of each of these sub-populations in isolation. This paper reports a method based on continuous-flow dielectrophoresis to separate live and dead cells

This work reports the demonstration of a thermopneumatic microfluidic actuator used to determine blood coagulation time. In this new system, the detection principle is the obstruction of a microfluidic channel by clotted blood. The sample actuation is done ...

The probe has support cylinder (214) that is slidingly provided in distal portion of internal lumen. Several shafts coupled to support cylinder and arranged to be selectively extended from distal end of elongated shaft. Several conductive traces provided o ...

Parylenes are used for a wide range of applications in microelectromechanical systems (MEMS) devices. However, their poor adhesion in a harsh liquid environment can limit the fabrication processes of complex MEMS and bioMEMS devices. Potassium hydroxide (K ...

Nanochannel conductance measurements are commonly performed to characterize nanofluidic devices Theoretical analysis and experimental investigations imply that the nanochannel conductance does not follow the macro-scale models. It is generally accepted tha ...

The simulation of integrated electromagnetic sensors and actuators can be performed in conjunction with the electronics to simulate a complete microsystem. A reluctant micro-relay and an inductive displacement sensor are characterized using finite elements. Macro-models using extracted parameters are coded with analog hardware description languages for circuit simulators, with the goal of global system simulation and optimization. The methodology is applicable to all integrated and hybrid transducers which

On-chip cell handling and analysis is given more and more interest, as new cytometry devices can be realised or efficiently combined and integrated. The developed sensor presents several improvements compared to other integrated flow cytometers. It is aimed at diagnostic applications for cell counting and separation in hematology and allows fast cell screening using simultaneous multi-frequency measurements. One major improvement is that the sensor sensitivity to the electrode properties is eliminated by a

A new surface micromachining method based on porous silicon formation followed by electropolishing is presented in this paper. It generates in a single electrochemical etch step a plate of porous silicon, releases it from the substrate without using a sacrificial layer and lifts it out of plane. The plate can be rotated by a thermal bimorph actuator. Large, flat, astuatable flip-up plates of porous silicon have been realized with a typical thickness of 30 mum and areas ranging from 250 mum by 750 mum to 240

A conductive composite photoresist has been developed for the direct photopatterning of electrodes. It is based on a dispersion of silver nanoparticles in SU8, a non-conductive, negative-tone photoresist. Manufactured structures have an electrical conducti ...

Philippe Renaud

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Cell viability assessment by flow cytometry using yeast as cell model

CMOS compatible fully integrated Mach-Zehnder interferometer in SOI technology

Multiple-frequency Impedance Measurements in Continuous Flow for the Evaluation of Electrical Lysis of Yeast Cells

Compact portable biosensor for arsenic detection in aqueous samples with Escherichia coli bioreporter cells

Microfabricated Cortical Neuroprostheses

Impedance spectroscopy flow cytometry: Parameters for label-free cell differentiation

SU-8 nanocomposite coatings with improved tribological performance for MEMS

Ceramic microcomponents by microstereolithography

Effect of input voltage frequency on the distribution of electrical stresses on the cell surface based on single-cell dielectrophoresis analysis

Neural priming of adipose-derived stem cells by cell-imprinted substrates*

A calcium ion-selective electrode array for monitoring the activity of HepG2/C3As in a microchannel

Separation of antibiotic-treated mycobacterial subpopulations using multiple-frequency dielectrophoresis

On-chip thermopneumatic actuation system for coagulation time measurement

Implantable neurological probe for identifying location of neurological target e.g. neurons, has stylet provided in internal lumen and configured to contact support cylinder to selectively extend shafts during implantation

Optimizing Parylene C Adhesion for MEMS Processes: Potassium Hydroxide Wet Etching

An improved model for predicting electrical conductance in nanochannels

Simulation of integrated electromagnetic device systems

On-chip impedance-spectroscopy for flow-cytometry using a differential electrode sensor

Porous silicon as new micro material for actuated 3D flip-up structures and its applications in microoptics

Conductive SU8 Photoresist for Microfabrication