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Sökning: WFRF:(Inganäs Olle) > Lundström Ingemar

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  • Assadi, A., et al. (författare)
  • Interaction of planar polymer Schottky barrier diodes with gaseous substances
  • 1994
  • Ingår i: Sensors and actuators. B, Chemical. - Elsevier. - 0925-4005. ; 20:1, s. 71-77
  • Tidskriftsartikel (refereegranskat)abstract
    • Conducting polymers appear very attractive as sensor materials either as the gas-sensitive component or as a matrix for easy immobilization of a specific substrate. The planar Schottky barrier diode with poly(3-octylthiophene), P3OT, as the semiconductor is used as a sensor for the detection of different gas species. The shifts in the current-voltage (C-V) characteristics as well as the C-V characteristics of the diodes due to water and ethanol vapour, ammonia gas and nitric oxide gases are studied. Nitric oxide and ammonia give the largest and most specific changes of the C-V characteristics. Nitric oxide has a doping effect, which increases the reverse current, while ammonia is the only gas that causes a negative change in the forward bias current of the I-V curve. The planar configuration of the Schottky barrier diode facilitates the absorption of gaseous species in the environment, and provides a simple method for production of gas sensors.
  • Filippini, Daniel, et al. (författare)
  • Computer screen photo-assisted spectral fingerprinting of luminescent polythiophene pH reporter
  • 2004
  • Ingår i: IEEE Sensors. Proceedings. - IEEE. - 1930-0395. ; 3, s. 1377-1380
  • Tidskriftsartikel (refereegranskat)abstract
    • The capability of the computer screen photo-assisted technique (CSPT)for the spectral fingerprinting of a photoactive polythiophene derivative (POWT) used as pH reporter is demonstrated. POWT is part of a family of industrial scalable materials, well established for organic electronics and biomedical applications, which is used here to demonstrate the capability of CSPT for tracing key spectral features. The ability of CSPTfor substance classification, corroborated by principal component analysis (PCA), successfully compares to standard spectroscopy, especially considering the involved equipments: CSPT is only a computer set and a web camera.
  • Immerstrand, Charlotte, 1974-, et al. (författare)
  • Altered impedance during pigment aggregation in Xenopus laevis melanophores
  • 2003
  • Ingår i: Medical and Biological Engineering and Computing. - 0140-0118. ; 41:3, s. 357-364
  • Tidskriftsartikel (refereegranskat)abstract
    • Melanophores are dark-brown pigment cells located in the skin of amphibia, fish and many invertebrates. The skin colour of these organisms is regulated by the translocation of pigment organelles, and the pigment distribution can be altered by external stimuli. The ability to change colour in response to stimuli makes these cells of interest for biosensing applications. It was investigated whether pigment aggregation in Xenopus laevis melanophores can be detected by impedance measurements performed in transparent microvials. The results show that cell attachment, cell spreading and pigment aggregation all resulted in impedance changes, seen particularly at the highest frequency tested (10 kHz). The mechanisms behind the impedance changes were investigated by the addition of latrunculin or melatonin, both of which cause pigment aggregation. The latrunculin-induced aggregation was associated with cell area decrease and filamentous actin (F-actin) breakdown, processes that can influence the impedance. Lack of F-actin breakdown and an increase in cell area during melatonin-induced aggregation suggest that some other intracellular process also contributes to the impedance decrease seen for melatonin. It was shown that impedance measurements reflect not only cell attachment and cell spreading, but also intracellular events.
  • Jager, Edwin, et al. (författare)
  • Biomedical applications of polypyrrole microactuators from single-cell clinic to microrobots
  • 2000
  • Ingår i: 1st Annual International, Conference On Microtechnologies in Medicine and Biology. 2000. - IEEE. - 0-7803-6603-4 ; s. 58-61
  • Konferensbidrag (övrigt vetenskapligt)abstract
    • Microtools that will be useful for the positioning and investigation microstructures must operate relevant environments, such as cell culture media or blood plasma. They must also be comparatively strong, and preferably allow a muscle like mode of movement. This is given by a novel family of actuators based on conjugated polymers (like polypyrrole, PPy). By miniaturising these structures using standard photolithographic techniques, the authors can reduce the size down to 10-micrometer dimensions and build mechanically active microdevices. These can be moved and positioned by applying a potential to dope or undope the PPy. These novel structures are now being developed as a unique microactuator technology, suitable for operation in applications coupled to cell biology and biomedicine
  • Jager, Edwin, 1973-, et al. (författare)
  • Microrobots for Micrometer-Size Objects in Aqueous Media : Potential Tools for Single-Cell Manipulation
  • 2000
  • Ingår i: Science. - 0036-8075. ; 288:5475, s. 2335-2338
  • Tidskriftsartikel (refereegranskat)abstract
    • Conducting polymers are excellent materials for actuators that are operated in aqueous media. Microactuators based on polypyrrole-goldbilayers enable large movement of structures attached to theseactuators and are of particular interest for the manipulationof biological objects, such as single cells. A fabrication methodfor creating individually addressable and controllable polypyrrole-goldmicroactuators was developed. With these individually controlledmicroactuators, a micrometer-size manipulator, or microroboticarm, was fabricated. This microrobotic arm can pick up, lift,move, and place micrometer-size objects within an area of about250 micrometers by 100 micrometers, making the microrobot an excellenttool for single-cell manipulation.
  • Jager, Edwin, 1973-, et al. (författare)
  • Perpendicular Actuation with Individually Controlled Polymer Microactuators
  • 2001
  • Ingår i: Advanced Materials. - 0935-9648. ; 13:1, s. 76-79
  • Tidskriftsartikel (refereegranskat)abstract
    • Actuator systems based on conducting polymers, such as polypyrole, with which three-dimensional movement can be controlled, are described. The Figure shows a combination of two such microactuators which are used to “kick” a glass bead across the surface of a silicon wafer. The microfabrication methods used to produce the systems are described and the potential uses, for example microrobotic arms, discussed.
  • Jager, Edwin, 1973-, et al. (författare)
  • Polypyrrole micro actuators
  • 1999
  • Ingår i: Synthetic metals. - 0379-6779. ; 102:1-3, s. 1309-1310
  • Tidskriftsartikel (refereegranskat)abstract
    • The doping and undoping of conjugated polymers is accompanied by a volume change. This volume change can be used to make micro-actuators. We have built polypyrrole (PPy) gold bilayer structures. The volume change of PPy induces a bending of the bilayer. We have made micro-actuators based on this principle, which have been examined with video-microscopy. Some applications for these microactuators are proposed, including opening and closing boxes for cell biology and nanoliter chemistry and micro-robotics.
  • Jager, Edwin W.H., et al. (författare)
  • The cell clinic closable microvials for single cell studies
  • 2002
  • Ingår i: Biomedical microdevices (Print). - 1387-2176. ; 4:3, s. 177-187
  • Tidskriftsartikel (refereegranskat)abstract
    • We present the development of a cell clinic. This is a micromachined cavity, or microvial, that can be closed with a lid. The lid is activated by two polypyrrole/Au microactuators. Inside the microvials two Au electrodes have been placed in order to perform impedance studies on single or a small number of cells. We report on impedance measurements on Xenopus leavis melanophores. We could measure a change in the impedance upon cell spreading and identify intracellular events such as the aggregation of pigment granules. The electrical data is correlated to optical microscopy.
  • Lundberg, Bo, et al. (författare)
  • Pressure-dependent electrical conductivity of polypyrrole
  • 1985
  • Ingår i: Molecular Crystals and Liquid Crystals vol. 118 : Proceedings of the International Conference on the Physics and Chemistry of Low-Dimensional Synthetic Metals (ISCM '84), Abano Terme 1984. ; s. 155-158
  • Konferensbidrag (refereegranskat)abstract
    • The results of pressure dependent electrical conductivity measurements in polypyrrole are consistent with a simple extension of the variable-range-hopping model of electronic transport in disordered media.
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