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Quist J.,MESA Institute for Nanotechnology | Sarajlic E.,SmartTip B.V. | Lai S.C.S.,MESA Institute for Nanotechnology | Lemay S.G.,MESA Institute for Nanotechnology
20th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2016 | Year: 2016

To analyze the molecular content of single cells, cell lysis is typically required, yielding a snapshot of cell behavior only. To follow complex molecular profiles over time, subcellular sampling methods potentially can be used, but to date these methods involve laborious offline analysis. Here we report a "tip chip" device for continuous online coupling of subcellular sampling and on-chip sample analysis. The device contains a hollow, sharp, out-of-plane tip connected to a microfluidic channel structure. After positioning a cell onto the tip using a fluidic force microscope, intracellular molecules diffuse into the microchannel and are directly analyzed using isotachophoresis.


Yamahata C.,Ecole Polytechnique Federale de Lausanne | Stranczl M.,Ecole Polytechnique Federale de Lausanne | Stranczl M.,Nivarox FAR S.A. | Sarajlic E.,SmartTip B.V. | And 2 more authors.
Journal of Microelectromechanical Systems | Year: 2012

A simple optical method is proposed for performing in-plane experimental modal analysis of micromachined structures with a conventional charge-coupled device (CCD) camera. The motion of a micromechanical device actuated by high-frequency sinusoidal forces (kilohertz range) is recorded at the fixed sampling rate of a camera (typically, 28 frames/s) which is configured with a short shutter aperture time (1/5000 s). Provided a CCD sensor with sufficient sensitivity, much information is contained in the video on the dynamics of the vibrating system despite the limited frame rate. Taking advantage of the theory of undersampling, we show that the dynamics of the systems with several-kilohertz bandwidth can be retrieved very easily. For demonstration purposes, we first study a push-pull electrostatic comb-drive actuator, which is a well-known damped harmonic oscillator system. Then, we show that our measurement method also provides useful information on the behavior of nonlinear systems. In particular, we can characterize the systems' superharmonic and subharmonic resonances in a straightforward way. © 2012 IEEE.


Dorig P.,ETH Zurich | Stiefel P.,ETH Zurich | Behr P.,ETH Zurich | Behr P.,Cytosurge LLC | And 9 more authors.
Applied Physics Letters | Year: 2010

The FluidFM technology uses microchanneled atomic force microscope cantilevers that are fixed to a drilled atomic force microscope cantilevers probeholder. A continuous fluidic circuit is thereby achieved extending from an external liquid reservoir, through the probeholder and the hollow cantilever to the tip aperture. In this way, both overpressure and an underpressure can be applied to the liquid reservoir and hence to the built-in fluidic circuit. We describe in this letter how standard atomic force microscopy in combination with regulated pressure differences inside the microchanneled cantilevers can be used to displace living organisms with micrometric precision in a nondestructive way. The protocol is applicable to both eukaryotic and prokaryotic cells (e.g., mammalian cells, yeasts, and bacteria) in physiological buffer. By means of this procedure, cells can also be transferred from one glass slide to another one or onto an agar medium. © 2010 American Institute of Physics.


Yamahata C.,Ecole Polytechnique Federale de Lausanne | Sarajlic E.,SmartTip B.V. | Krijnen G.J.M.,University of Twente | Gijs M.A.M.,Ecole Polytechnique Federale de Lausanne
Journal of Microelectromechanical Systems | Year: 2010

In-plane linear displacements of microelectromechanical systems are measured with subnanometer accuracy by observing the periodic micropatterns with a charge-coupled device camera attached to an optical microscope. The translation of the microstructure is retrieved from the video by phase-shift computation using discrete Fourier transform analysis. This approach is validated through measurements on silicon devices featuring steep-sided periodic microstructures. The results are consistent with the electrical readout of a bulk micromachined capacitive sensor, demonstrating the suitability of this technique for both calibration and sensing. Using a vibration isolation table, a standard deviation of σ = 0.13 nm could be achieved, enabling a measurement resolution of 0.5 nm (4 σ) and a subpixel resolution better than 1/100 pixel. © 2006 IEEE.


Sarajlic E.,SmartTip B.V. | Sarajlic E.,Tokyo International University | Yamahata C.,Ecole Polytechnique Federale de Lausanne | Yamahata C.,Tokyo International University | And 2 more authors.
Journal of Microelectromechanical Systems | Year: 2010

Electrostatic stepper motors, also known as synchronous variable-capacitance motors, operate by utilizing the electrical energy stored in the variable capacitances formed between the poles of their rotor and stator. We present the design, modeling, and experimental characterization of a three-phase rotary stepper micromotor that employs a flexural suspension of the rotor to avoid any frictional contact during operation, providing precise, repeatable, and reliable bidirectional stepping motion without feedback control. A monolithic micromotor with high-aspect-ratio poles and an integrated three-phase electrical network was fabricated in a standard single-crystal silicon wafer by combining vertical trench isolation and bulk micromachining. The experimental characterization of a prototype having a diameter of 1.4 mm has demonstrated a rotational range of 2613 at 75 V and a maximum speed of 1.67 hbox{ms}. Half-stepping and microstepping operation modes were demonstrated with step sizes of 1/6 and 1/48, respectively. The exceptional performance of the motor makes it suitable for use in hard-disk drives as a secondary stage actuator to maintain a constant orientation between the read/write head and the recording tracks. © 2006 IEEE.


Stranczl M.,Ecole Polytechnique Federale de Lausanne | Sarajlic E.,SmartTip B.V. | Fujita H.,Tokyo International University | Gijs M.A.M.,Ecole Polytechnique Federale de Lausanne | Yamahata C.,Ecole Polytechnique Federale de Lausanne
Journal of Microelectromechanical Systems | Year: 2012

Flexible bearings are advantageous for microelectromechanical systems as they enable precise, accurate, repeatable, and reliable motion without frictional contact. Based on the principle of a rotary folded-beam suspension, we have designed, fabricated, modeled, and characterized an electrostatic rotary stepper micromotor in silicon. Using 3-D finite-element analysis simulations that were corroborated by extensive characterizations performed in quasi-static, transient, and dynamic regimes, we could establish a consistent electromechanical model of the motor. In particular, dynamic nonlinearities such as superharmonic and subharmonic resonances are well described by the proposed model. Two prototypes of monolithic three-phase stepper motors have been fabricated with standard silicon-on-insulator (SOI) technology, using either a two-mask or a single-mask process. The two-mask SOI motor has a rotor diameter of 1.4 mm and has an angular range of 30° (± 15°) for a 65-V (130 V pp) sinusoidal actuation. The single-mask SOI motor has a rotor diameter of 1.8 mm and incorporates a differential capacitive sensor for angular position measurement. It reaches a maximum angular speed of 1°/ms and has an angular range of 30° for a 23-V (46 V pp) sinusoidal actuation. The exceptional performance of the motor and the demonstration of successful capacitive sensing make it suitable for use as an active joint module in future microrobotic applications. © 2012 IEEE.


Stranczl M.,Ecole Polytechnique Federale de Lausanne | Sarajlic E.,SmartTip B.V. | Krijnen G.J.M.,University of Twente | Fujita H.,University of Tokyo | And 2 more authors.
Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) | Year: 2011

We present the design, modeling and characterization of a 3-phase electrostatic rotary stepper micromotor. The proposed motor is a monolithic device fabricated using silicon-on-insulator (SOI) technology. The rotor is suspended with a frictionless flexural pivot bearing and reaches an unprecedented rotational range of 30° (+/- 15°) at 65 V. We have established a mechanical model of the deformation structure and performed finite element analysis (FEA) simulations of the dynamic properties. These studies are consistent with the extensive experimental characterization performed in the quasi-static, transient, and dynamic regimes.


Yamahata C.,Ecole Polytechnique Federale de Lausanne | Sarajlic E.,SmartTip B.V. | Stranczl M.,Ecole Polytechnique Federale de Lausanne | Krijnen G.J.M.,University of Twente | Gijs M.A.M.,Ecole Polytechnique Federale de Lausanne
2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11 | Year: 2011

We present a straightforward method for measuring in-plane linear displacements of microelectromechanical systems (MEMS) with subnanometer resolution. The technique is based on Fourier transform analysis of a video recorded with a Charge-Coupled Device (CCD) camera attached to an optical microscope and can be used to characterize any device featuring periodic patterns along the direction of motion. Using a digital microscope mounted on a vibration isolation table, a subpixel resolution better than 1/100 pixel could be achieved, enabling quasi-static measurements with a resolution of 0.5 nm. © 2011 IEEE.


Schon P.,MESA Institute for Nanotechnology | Geerlings J.,MESA Institute for Nanotechnology | Tas N.,MESA Institute for Nanotechnology | Sarajlic E.,MESA Institute for Nanotechnology | Sarajlic E.,SmartTip B.V.
Analytical Chemistry | Year: 2013

We report here first results obtained on a novel, in situ renewable mercury microelectrode integrated into an atomic force microscopy (AFM) cantilever. Our approach is based on a fountain pen probe with appropriate dimensions enabling reversible filling with (nonwetting) mercury under changing the applied pressure at a connected mercury supply in a dedicated experimental setup. The fountain pen probe utilizes a special design with vertical pillars inside the channel to minimize mechanical perturbation. In proof of principle experiments, dropping and hanging mercury drop were observed as a function of the applied pressure at the external mercury supply. Electrical conductivity occurred only through the mercury after filling, and the empty fountain pen probe showed excellent electrical insulation. This was demonstrated by chronoamperometric measurements in the electrolyte and by mechanical and electrical contacting of an ITO substrate with a mercury-filled and empty probe in air. Finally, cyclic voltammetry and square wave voltammetry were done in a static mercury electrode fountain pen configuration, demonstrating the principle usability of the mercury probe for electrochemical studies. Our findings are of fundamental importance as they enable further integration of a renewable mercury electrode probe into an AFM setup, which is the subject of ongoing work. © 2013 American Chemical Society.


The present invention relates to a method of manufacturing a probe comprising a cantilever with a conduit. According to the invention, an etchant window is provided in a layer covering an elongated sacrificial conduit core that is to form the conduit. This allows for an etching process where the elongated sacrificial conduit core is etched away before all material of a substrate is etched away, the remaining material of the substrate material making the probe stronger without being in the way during use of the probe.

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