| 1. |
- Immerstrand, Charlotte, 1974-, et al.
(författare)
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Altered impedance during pigment aggregation in Xenopus laevis melanophores
- 2003
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Ingår i: Medical and Biological Engineering and Computing. - 0140-0118 .- 1741-0444. ; 41:3, s. 357-364
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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.
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| 2. |
- Jager, Edwin, et al.
(författare)
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Biomedical applications of polypyrrole microactuators : from single-cell clinic to microrobots
- 2000
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Ingår i: 1st Annual International, Conference On Microtechnologies in Medicine and Biology. 2000. - : IEEE. - 0780366034 ; , s. 58-61
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)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
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| 3. |
- Jager, Edwin W.H., et al.
(författare)
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The cell clinic : closable microvials for single cell studies
- 2002
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Ingår i: Biomedical microdevices (Print). - 1387-2176 .- 1572-8781. ; 4:3, s. 177-187
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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.
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