Freiburg, Germany
Freiburg, Germany
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Zappe H.,IMTEK
Optics InfoBase Conference Papers | Year: 2016

We will discuss how collaboration between optical engineers, chemists, and technologists has led to new directions in waveguide based integrated optics, moving away from wafer-level processing toward roll-to-roll printing of complex, highly-functional optical circuits. © OSA 2016.

Lorenz R.,Albert Ludwigs University of Freiburg | Benk C.,Albert Ludwigs University of Freiburg | Bock J.,Albert Ludwigs University of Freiburg | Stalder A.F.,Albert Ludwigs University of Freiburg | And 5 more authors.
Magnetic Resonance in Medicine | Year: 2012

The aim of this study was to evaluate the performance of a closed circuit MR compatible pneumatically driven pump system using a ventricular assist device as pulsatile flow pump for in vitro 3D flow simulation. Additionally, a pressure control unit was integrated into the flow circuit. The performance of the pump system and its test-retest reliability was evaluated using a stenosis phantom (60% lumen narrowing). Bland-Altman analysis revealed a good test-retest reliability (mean differences = -0.016 m/s, limits of agreement = ±0.047 m/s) for in vitro flow measurements. Furthermore, a rapid prototyping in vitro model of a normal thoracic aorta was integrated into the flow circuit for a direct comparison of flow characteristics with in vivo data in the same subject. The pneumatically driven ventricular assist device was attached to the ascending aorta of the in vitro model to simulate the beating left ventricle. In the descending part of the healthy aorta a flexible stenosis was integrated to model an aortic coarctation. In vivo and in vitro comparison showed significant (P = 0.002) correlations (r = 0.9) of mean velocities. The simulation of increasing coarctation grade led to expected changes in the flow patterns such as jet flow in the post-stenotic region and increased velocities. Copyright © 2011 Wiley-Liss, Inc.

News Article | November 14, 2016

A team of researchers from the University of Freiburg has developed a system inspired by biology that can detect several different antibiotics in human blood or other fluids at the same time. This biosensor system could be used for medical diagnostics in the future, especially for point-of-care testing in doctors' practices, on house calls and in pharmacies, as well as in environmental and food safety testing. The researchers focused their study on the antibiotics tetracycline and streptogramin in human blood. "The analysis takes only 10 minutes, from sample to result," said the microsystems engineer Dr. Can Dincer, who is the head of the research team: "Our study was about demonstrating the applicability of the platform." The researchers have recently published their results in Analytical Chemistry. Based on these findings, the group is currently working on developing a method to determine how quickly the human body breaks down antibiotics, thus enabling the dosage of medications to be adjusted to each patient. "This technology could pave the way for personalized antibiotic treatments in the future," Dincer said. The all-too-frequent use of antibiotics in human and veterinary medicine causes pathogens to develop resistance. Multidrug resistant bacteria are the reason for an increasing number of life-threatening infections that are difficult to treat with medications available today. In this context, biosensors have so much potential in research, since they are inexpensive and easy to work with. It is expected that biosensors can be employed to customize antibiotic treatments to fit each patient`s requirements, thereby decreasing the development of resistant bacteria in the future. The electrochemical biosensor platform was developed by Prof. Dr. Gerald Urban's research group. It works with extremely small amounts of liquid. "The major advantage of this system is that we can measure up to eight different substances at the same time, quickly and simply," Dincer said. The researchers combined their chip technology with a method developed earlier by the bioengineering expert Prof. Dr. Wilfried Weber, also from the University of Freiburg. The method is based on a naturally occurring sensor protein in resistant bacteria to recognize antibiotics and activate their defence mechanisms. These bacterial sensors react quickly, sensitively and specifically to antibiotics, which makes them ideal for analytical testing. Essentially, the bacteria are providing the researchers with a tool that can be applied to fight them back in the long-run. The eight researchers from the University of Freiburg involved in the interdisciplinary study include Lucas Armbrecht, Dr. Can Dincer, Dr. Jochen Kieninger, André Kling, Edvina Qelibari and Prof. Dr. Gerald Urban -- all from the Sensors Lab of the Department of Microsystems Engineering (IMTEK) -- as well as Claire Chatelle and Prof. Dr. Wilfried Weber from the Synthetic Biology Department of the BIOSS Centre for Biological Signalling Studies cluster of excellence and the Faculty of Biology.

Imtek and Imec | Date: 2011-09-16

A probe for recording and/or stimulating brain activity includes a connecting portion and at least one shank extending from the connecting portion. The at least one shank includes a first side, a second side opposed to the first side, and a fin protruding substantially perpendicularly from the second side and running on at least a part of a length of the at least one shank. The first side includes at least one recording and/or stimulating site.

Imec and Imtek | Date: 2013-03-20

A probe for brain recording or stimulation and a method for fabricating the same, the probe comprising one or more shanks having a same orientation, wherein each of said shanks has a first side and a second side opposed to said first side and comprises at least one recording and/or stimulating site on said first side and a fin protruding perpendicularly from said second side and running on at least a part of the length of said shank along said same orientation.

Czurratis D.,Robert Bosch GmbH | Beyl Y.,Robert Bosch GmbH | Zinober S.,Robert Bosch GmbH | Larmer F.,Robert Bosch GmbH | Zengerle R.,IMTEK
Journal of Micromechanics and Microengineering | Year: 2015

On-chip storage of liquids is one of the major challenges of polymer-based Lab-On-A-Chip (LoC) devices. To ensure long-term storage of even highly volatile reagents in polymer disposal LoC cartridges, robust reagent storage concepts are necessary. Tubular bags, so-called stick packs, are widely used in the packaging industry. They offer sufficient vapor barrier properties for liquid storage. Here we present a polymer multilayer LoC-stack with integrated stick packs for the long-term storage of liquid reagents required for diagnostic applications. The storage concept fulfils two main requirements: firstly, the long-term storage of reagents in stick packs without significant losses or interaction with the surroundings and secondly, the on-demand release of liquids, which is realized by the delamination of a stick pack's peel seam through pneumatic pressure. Furthermore, effects on the opening behavior of stick packs through accelerated aging were investigated after different storage conditions to proof repeatability. This concept enables on-chip storage of liquid reagents at room temperature and allows the implementation in different pressure driven LoC devices or similar applications. Since liquid storage in stick packs is well-established, emerging fields such as Lab-On-A-Chip combined with novel reagent release mechanisms should be of great interest for the commercialization of life science products. © 2015 IOP Publishing Ltd.

Herboth T.,Robert Bosch GmbH | Guenther M.,Robert Bosch GmbH | Zeiser R.,IMTEK | Wilde J.,IMTEK
2013 14th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2013 | Year: 2013

The aim of this study was to analyse the stress state in silicon dies joined by Low Temperature Joining Technology (LTJT) based on measurements and simulation results. The focus was to establish a method to determine the initial stress state and stress-free temperature in a silicon die attached to a copper substrate after the joining process. An approach to analyse the evolution of the stress state after sintering and during thermal cycling was developed. © 2013 IEEE.

Hildenbrand J.,IMTEK | Peter C.,Fraunhofer Institute for Physical Measurement Techniques | Lamprecht F.,Fraunhofer Institute for Physical Measurement Techniques | Kurzinger A.,Fraunhofer Institute for Physical Measurement Techniques | And 6 more authors.
Microsystem Technologies | Year: 2010

A novel micromachined thermal emitter for fast transient temperature operation is presented. Compared to most commercial available thermal emitters, the one here presented is able to operate in a pulsed mode. This allows the use of lock-in techniques or pyrodetectors in the data acquisition without the use of an optical chopper for light modulation. Therefore, these types of thermal emitters are very important for small filter photometers. Several hot-plate suspension concepts were studied in order to find a design with excellent mechanical stability and high thermal decoupling. In contrary to the classical spider suspension design, a novel approach based on a non-axis-symmetric design is presented. The thermal emitters are fabricated using silicon on insulator technology and KOH-etching. The emitters are heated with Pt-meanders. For temperature determination an additional Pt-structure is deposited onto the hot-plates. The emitters are mounted in TO-5 housings using a ceramic adhesive and gold wire bonding. The used operation temperature is 750°C. In pulsed operation it's important to have a large modulation depth in terms of thermal radiation intensity in the needed spectral range. The maximal reachable modulation depth ranges from ambient temperature to steady state temperature. A modulation frequency of 5 Hz still allows using nearly the maximum modulation depth. A parameterized finite element model was realized and adapted to the measured data. This was the basis for the numerical optimization procedure for a new improved design. © 2010 Springer-Verlag.

Rademacher S.,Fraunhofer Institute for Physical Measurement Techniques | Wollenstein J.,IMTEK
European Conference on Smart Objects, Systems and Technologies, Smart SysTech 2014 | Year: 2014

This paper focuses on a gas sensor node for the use in disaster management. The aim is the development of a low cost, low power system for spatially resolved, accurate gas measurements. This is achieved through the integration of various low cost and low power gas, temperature and humidity sensors, combined with intelligent signal processing and information fusion. Furthermore, a low cost localization system for the relative positioning of the sensor nodes is implemented. © VDE VERLAG GMBH Berlin Offenbach, Germany.

Specific and sensitive nucleic acid (NA) testing in research and clinical diagnostics is usually performed by use of labeled oligonucleotide probes. However, the use of target-specific fluorogenic probes increases the cost of analysis. Therefore, universal sequence-dependent (USD) NA detection methods have been developed to facilitate cost-effective target detection using standardized reagents.We provide a comprehensive review of the current methods for fluorescence-based USD NA detection. Initially, we focus on the emergence of these methods as a means to overcome the shortcomings of common NA detection methods, such as hydrolysis probes and molecular beacons. Thereafter, we provide a critical evaluation of the individual detection methods. These methods include (a) target amplification with bipartite primers introducing a universal detection tag to the amplicon (UniPrimer PCR, universal fluorescence energy transfer probe PCR, attached universal duplex probe PCR, and universal strand displacement amplification) or combined with bipartite probes comprising a universal detection region (mediator probe PCR, universal strand displacement amplification, universal quenching probe PCR) and (b) amplification-independent assays employing either a universal variant of the invader assay or universal NA hybridization sensors. We discuss differences between the methods and review clinical applications.The current methods for USD NA testing are cost-effective and flexible and have concordant analytical performance in comparison with common probe-based techniques. They can detect any target sequence by the simple use of a label-free, low-cost primer or probe combined with a universal fluorogenic reporter. The methods differ in the number of target specificities, capability of multiplexing, and incubation requirements (isothermal/thermocycling). Extensive clinical applications comprise detection of single-nucleotide polymorphisms, study of gene expression, in situ PCR, and quantification of pathogen load.

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