Peter Koltay

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Jens Ducrée

Dublin City University

University of Calgary

Joey Choi

Dong Jin Shin

Johns Hopkins University School of Medicine

Samuel Marre

University of Bordeaux (France)

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Papers by Peter Koltay

Teflon-carbon black as new material for the hydrophobic patterning of polymer labs-on-a-chip

TRANSDUCERS 2009 - 2009 International Solid-State Sensors, Actuators and Microsystems Conference, 2009

We provide a new method for the selective surface patterning of microfluidic chips with hydrophob... more We provide a new method for the selective surface patterning of microfluidic chips with hydrophobic fluoropolymers which is demonstrated by the fabrication of hydrophobic valves. It enables efficient optical quality control for the surface patterning thus permitting the lowcost production of highly reproducible hydrophobic valves. Specifically, a fluoropolymer-solvent-dye solution based on carbon black (CB) is presented which creates superhydrophobic surfaces (contact angle = 157.9°) on chips made from cyclic olefin copolymer (COC). It further provides good visibility for the quality control (QC) in polymer labs-on-a-chip and increases the burst pressure of hydrophobic valves. Finally, an application which aims for the amplification of mRNA on-chip and relies on the defined flow control by hydrophobic valves is presented. Here, the QC in combination with the Teflon-CB coating improves the average standard deviation of the burst pressures from 14.5% down to 6.1 % compared to solely Teflon-coated valves.

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Theoretical evaluation of the dispensing well plate method (DWP part II)

Sensors and Actuators a Physical, Oct 29, 2004

The “dispensing well plate” (DWP™) method is a technique to deliver fluidic jets or droplets with... more The “dispensing well plate” (DWP™) method is a technique to deliver fluidic jets or droplets with volumes of several nanoliters contact free to targets like micro well plates or slides. A cheap and simple pneumatic actuation mechanism allows for the simultaneous delivery of a large number of different liquids. In this paper the dispensing dynamics of a DWP-type nanodispenser is

Vorrichtung und Verfahren zur ortsaufgelösten chemischen Stimulation

Increasing muDMFC efficiency by passive CO2 bubble removal and discontinuous operation

J Micromechanic Microengineer, 2006

A new concept that enables fully passive CO2 gas bubble removal in micro direct methanol fuel cel... more A new concept that enables fully passive CO2 gas bubble removal in micro direct methanol fuel cells (muDMFCs) is presented. The original concept behind the presented degassing structure (flowfield) is based on microchannels with a T-shaped cross section. These channels have defined tapering angles over their cross section (alpha) and along their axis (beta). The tapered channel design creates an intrinsic transport mechanism that removes the gas bubbles from the electrodes by capillary forces only. Computational fluid dynamic (CFD) simulations have been used to determine applicable opening angles of alpha = 5° and beta = 1.5°. The experimental verification was done by using a transparent flowfield to show the passive bubble removal as well as with a fully operational muDMFC. During the operation, the fuel cell delivered an output of up to 8 mW cm-2 without the need for external pumping in short-term measurements. During the long-term measurements, discontinuous pumping showed the highest fuel cell efficiency compared to the continuously pumped fuel supply.

NOVEL STRUCTURE FOR PASSIVE C02 DEGASSING INÂ¿ iDMFC

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The dispensing well plate: a novel nanodispenser for the multiparallel delivery of liquids (DWP Part I)

Sensors and Actuators a Physical, Oct 1, 2004

This paper reports on a novel dispensing system for the massive parallel delivery of liquid volum... more This paper reports on a novel dispensing system for the massive parallel delivery of liquid volumes in the range of 50nL. Due to the similarity of the device to conventional microwell plates used for storage of liquids, the device has been termed “dispensing well plate” (DWP). In contrast to other known microdispensers the DWP can consist of up to 1536

Vorrichtung mit einem ein Medium führenden Kanal und Verfahren zur Entfernung von Einschlüssen

Device Comprising a Channel Carrying a Medium and Method for Removing Inclusions

Method For Operating a Direct Oxidation Fuel Cell and Corresponding Arrangement

Pipettenspitze, Pipetiervorrichtung, Pipettenspitzen-Betätigungsvorrichtung und Verfahren zum Pipetieren im nL-Bereich

Design of a Passive and Portable DMFC Operating in All Orientations

2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems, 2009

A microfluidic layout concept for passive and portable Direct Methanol fuel Cells (DMFCs) is pres... more A microfluidic layout concept for passive and portable Direct Methanol fuel Cells (DMFCs) is presented. We proofed this concept by developing a DMFC that continuously runs for 40 hours in all orientations without the need for any active components such as pumps or valves. In contrast to our previous work [1], the system now is truly portable. In any orientation of the DMFC, a bubble driven self regulating supply mechanism safely removes carbon dioxide and transports at least 3.5 times more methanol to the anode than critically needed to sustain DMFC operation. On the cathode, diffusive oxygen supply and the transport of the reaction product water along a capillary gradient out of the DMFC ensures a stable performance. Compared to our previous work [1], the power output was increased by a factor of 2.5 and reached p = 5.5 mW cm -2 . A stable power output for 40 hours of p = 4 mW cm -2 was achieved for the preferred vertical position with bubbles moving against buoyancy forces. In the most challenging horizontal position with the anode facing downwards, a power output of at least p = 3.1 mW cm -2 was reached for the same period of time.

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Pipette tip, pipette device, pipette tip actuating device and pipetting method in the nanolitre range

Device and method for dosing small amounts of liquid

Vorrichtung und Verfahren zum Erzeugen eines Tropfens einer Flüssigkeit

Apparatus and method for dispensing cells or particles confined in a free flying droplet

Simulation of a micro dispenser using lumped models

In this paper the modelling of a micro dispenser by system simulations according to fluidic netwo... more In this paper the modelling of a micro dispenser by system simulations according to fluidic network theory is reported. The dispensing device under consideration (the so called "Nano-Jet" dispenser) is described in detail in . In this device the dispensing process is triggered by the displacement of a diaphragm. Upon this actuation a free jet of liquid in the volume range of 10 nl to 100 nl is ejected from the orifice of the device. Thus the system is in some sense similar to an ink-jet print head except the fact, that a liquid jet is generated rather than droplets and a much larger volume is delivered. To set up a system model for the sketched device first a lumped model for a circular plate is derived which accounts for all essential features of fluid structure interaction (FSI) in the system. Then the plate model is combined with lumped elements of a fluidic channel and a nozzle to yield the system model of the dispenser. The results obtained with the system model are compared to experimental data in terms of ejected volume and influence of system parameters.

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Non-Contact Nanoliter & Picoliter Liquid Dispensing

TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference, 2007

This paper presents an introduction to non-contact dispensing technologies gaining increasingly i... more This paper presents an introduction to non-contact dispensing technologies gaining increasingly importance in numerous application fields, ranging from the life sciences and medical applications to industrial fabrication. Besides a brief overview on typical applications the basic dimensionless numbers to describe droplet breakup are introduced. Based on this formalism criteria for droplet breakup are given and a classification of droplet dispensers

Fully passive degassing and fuel supply in direct methanol fuel cells

2008 IEEE 21st International Conference on Micro Electro Mechanical Systems, 2008

In this paper a micro direct methanol fuel cell (µDMFC) is presented, which is operated in a comp... more In this paper a micro direct methanol fuel cell (µDMFC) is presented, which is operated in a completely passive way, i.e. the cell does not require an external pump for fuel supply. The surface energy of deformed CO 2 bubbles, generated as a reaction product during DMFC operation, is employed to supply methanol to the anode. In contrast to a digital valve based approach presented earlier by Meng et. al.

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Sub-µ structured lotus surfaces manufacturing

2008 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS, 2008

Sub-micro structured surfaces allow modifying the behavior of polymer films or components. Especi... more Sub-micro structured surfaces allow modifying the behavior of polymer films or components. Especially in micro fluidics a lotus-like characteristic is requested for many applications. Structure details with a high aspect ratio are necessary to decouple the bottom and the top of the functional layer. Unlike to stochastic methods, patterning with a LIGA-mold insert it is possible to structure surfaces very uniformly or even with controlled variations (e.g. with gradients). In this paper we present the process chain to realize polymer sub-micro structures with minimum lateral feature size of 400 nm and up to 4 µm high.

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<title>Microdispenser array for highly parallel and accurate liquid handling</title>

BioMEMS and Smart Nanostructures, 2001

Liquid handling of volumes down to a few nanoliters is a key issue for modern bioanalytical and p... more Liquid handling of volumes down to a few nanoliters is a key issue for modern bioanalytical and pharmaceutical research and industry. In this paper we present a modular dispensing device for the highly accurate delivery of liquids in the range of 10 nL -500 nL at a precision of better than 5 % and a dosage rate up to 1000 nL/s. The reported dispensing technology is based on a fast mechanical displacement of liquid within a micromachined silicon chip (termed "dosage chip"). It overcomes limitations known from piezo-drop-on-demand dispensers or syringe-solenoid systems presently used in laboratory automation. The accurate and very robust multi channel system which is modularly built out of individual dispensers is able to handle a variety of different liquids simultaneously. A wide range of liquids with different physical properties can be handled with an up to now unequalled precision in that volume range. The working principle of the device as well as newest characterization results are presented.

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Teflon-carbon black as new material for the hydrophobic patterning of polymer labs-on-a-chip

TRANSDUCERS 2009 - 2009 International Solid-State Sensors, Actuators and Microsystems Conference, 2009

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Theoretical evaluation of the dispensing well plate method (DWP part II)

Sensors and Actuators a Physical, Oct 29, 2004

Vorrichtung und Verfahren zur ortsaufgelösten chemischen Stimulation

Increasing muDMFC efficiency by passive CO2 bubble removal and discontinuous operation

J Micromechanic Microengineer, 2006

NOVEL STRUCTURE FOR PASSIVE C02 DEGASSING INÂ¿ iDMFC

Download

The dispensing well plate: a novel nanodispenser for the multiparallel delivery of liquids (DWP Part I)

Sensors and Actuators a Physical, Oct 1, 2004

Vorrichtung mit einem ein Medium führenden Kanal und Verfahren zur Entfernung von Einschlüssen

Device Comprising a Channel Carrying a Medium and Method for Removing Inclusions

Method For Operating a Direct Oxidation Fuel Cell and Corresponding Arrangement

Pipettenspitze, Pipetiervorrichtung, Pipettenspitzen-Betätigungsvorrichtung und Verfahren zum Pipetieren im nL-Bereich

Design of a Passive and Portable DMFC Operating in All Orientations

2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems, 2009

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Pipette tip, pipette device, pipette tip actuating device and pipetting method in the nanolitre range

Device and method for dosing small amounts of liquid

Vorrichtung und Verfahren zum Erzeugen eines Tropfens einer Flüssigkeit

Apparatus and method for dispensing cells or particles confined in a free flying droplet

Simulation of a micro dispenser using lumped models

Download

Non-Contact Nanoliter & Picoliter Liquid Dispensing

TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference, 2007

Fully passive degassing and fuel supply in direct methanol fuel cells

2008 IEEE 21st International Conference on Micro Electro Mechanical Systems, 2008

Download

Sub-µ structured lotus surfaces manufacturing

2008 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS, 2008

Download

<title>Microdispenser array for highly parallel and accurate liquid handling</title>

BioMEMS and Smart Nanostructures, 2001

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