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- Eriksson Linsmeier, Cecilia, et al.
(författare)
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Soft tissue reactions evoked by implanted gallium phosphide.
- 2008
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Ingår i: Biomaterials. - : Elsevier BV. - 1878-5905 .- 0142-9612. ; 29:35, s. 4598-4604
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Tidskriftsartikel (refereegranskat)abstract
- Neural devices may play an important role in the diagnosis and therapy of several clinical conditions, such as stroke, trauma or neurodegenerative disorders, by facilitating motor and pain control. Such interfaces, chronically implanted in the CNS, need to be biocompatible and have the ability to stimulate and record nerve signals. However, neural devices of today are not fully optimized. Nanostructured surfaces may improve electrical properties and lower evoked tissue responses. Vertical gallium phosphide (GaP) nanowires epitaxially grown from a GaP surface is one way of creating nanostructured electrodes. Thus, we chose to study the soft tissue reactions evoked by GaP surfaces. GaP and the control material titanium (Ti) were implanted in the rat abdominal wall for evaluation of tissue reactions after 1, 6, or 12 weeks. The foreign-body response was evaluated by measuring the reactive capsule thickness and by quantification of ED1-positive macrophages and total cells in the capsule. Furthermore, the concentration of Ga was measured in blood, brain, liver and kidneys. Statistically significant differences were noticed between GaP and Ti at 12 weeks for total and ED1-positive cell densities in the capsule. The chemical analysis showed that the concentration of Ga in brain, liver and kidneys increased during 12 weeks of implantation, indicating loss of Ga from the implant. Taken together, our results show that the biocompatible properties of GaP are worse than those of the well-documented biomaterial Ti.
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- Johansson, Fredrik, et al.
(författare)
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Nanomodified surfaces and guidance of nerve cell processes
- 2008
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Ingår i: Journal of Vacuum Science and Technology B. - : American Vacuum Society. - 1520-8567 .- 1071-1023. ; 26:6, s. 2558-2561
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Konferensbidrag (refereegranskat)abstract
- Axonal growth and guidance were studied on different micro- and nanostructured surfaces. Nanoimprinted grooves in a polymer, epitaxial III/V nanowires, porous silicon patterns, and chemically altered surfaces were all shown to induce axonal guidance. Neurons were also found to be able to attach and grow on gallium phosphide nanowires without compromising cell survival. The results are important for the construction of a new generation of neuroelectrical interfaces, including high spatial resolution electrodes. The advantages of the different nanostructured surfaces are discussed.
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- Ekström, Simon, et al.
(författare)
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Integrated selective enrichment target (ISET) - A generic microfabricated sample preparation device
- 2005
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Ingår i: Micro Total Analysis Systems 2004, Vol 2. - 0260-6291. - 9780854048960 ; :297, s. 548-550
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Konferensbidrag (refereegranskat)abstract
- A combined sample preparation and sample presentation device, Integrated Selective Enrichment Target (ISET), consisting of an array with 96 perforated nanovials is described. Each perforated nanovial can be filled with soild-phase extraction media for purification and concentration of biomolecules prior to mass spectrometry. The ISET platform provides an efficient, economic and generic sample treatment process, allowing for rapid in-parallel handling of minute sample volumes, with a minimum of sample transfers.
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| 6. |
- Ekström, Simon, et al.
(författare)
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Miniaturized solid-phase extraction and sample preparation for MALDI MS using a microfabricated integrated selective enrichment target
- 2006
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 5:5, s. 1071-1081
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Tidskriftsartikel (refereegranskat)abstract
- A microfabricated proteomic sample preparation and sample presentation device, Integrated Selective Enrichment Target, (ISET), comprising an array of 96 perforated nanovials is described. Each perforated nanovial can be filled with solid-phase extraction media for purification and concentration of peptides prior to matrix-assisted laser desorption/ionization mass spectrometry (MALDI IVIS). The validity of the ISET sample preparation is shown by analysis of low nM-pM standard samples, as well as biological samples. The ISET solid-phase extraction sample preparation was compared to ZipTip and MassPREP PROtarget sample preparation, demonstrating a superior performance with respect to number of detected peptides and signal intensity of detected peptides.
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| 7. |
- Ekström, Simon, et al.
(författare)
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Polymeric integrated selective enrichment target (ISET) for solid-phase-based sample preparation in MALDI-TOF MS
- 2007
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Ingår i: Journal of Mass Spectrometry. - : Wiley. - 1076-5174 .- 1096-9888. ; 42:11, s. 1445-1452
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Tidskriftsartikel (refereegranskat)abstract
- d A polymer microfabricated proteomic sample preparation and MALDI MS sample presentation device, the integrated selective enrichment target (ISET), comprising an array of perforated nanovials is reported. Each perforated nanovial can be filled with selective extraction media (microbeads) for purification and concentration of protein/peptides prior to matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). The main areas covered are the influence of the molding-process-induced surface roughness and how to address the lack of inherent conductivity in the polyetheretherketone (PEEK) material for optimal MALDI MS readout. Application of the disposable polymeric ISET devices for solid-phase extraction and phosphopeptide capture is also demonstrated.
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- Evander, Mikael, et al.
(författare)
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Acoustic Trapping: System Design, Optimization and Applications
- 2006
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Ingår i: Proceedings of the sixth Micro Structure Workshop. ; 1, s. 33-33
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Konferensbidrag (refereegranskat)abstract
- Manipulation, separation and trapping of particles and cells are very important tools in today's bioanalytical and medical field. The acoustic no-contact trapping method presented at earlier MSW 2004 provides a flexible platform for performing cell and particle assays in a perfusion-based microsystem. To further develop the system microfabricated glass channels are now used, resulting in shorter fabrication times and a very inert channel material. The fluidic design has been revised to minimise the risks of leaking and hydrodynamic focusing has been incorporated to ensure a high trapping efficiency. A change of piezoelectric materials has resulted in less thermal losses in the material, higher reproducibility and shorter manufacturing time. The trapping force was estimated by calculating the fluid force exerted on a single particle levitated in the standing wave as a reference. The temperature increase due to the losses in the transducer was measured using a fluorescent dye, indicating a maximum temperature increase of 10 degrees Celsius. Live cells have been trapped and shown to be viable while still suspended in the standing wave, thus making it possible to do on-line studies on, for example, drug response of cell populations.
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| 9. |
- Gustavsson, Per, et al.
(författare)
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Neurite guidance on protein micropatterns generated by a piezoelectric microdispenser
- 2007
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Ingår i: Biomaterials. - : Elsevier BV. - 1878-5905 .- 0142-9612. ; 28:6, s. 1141-1151
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we developed a microdispenser technique in order to create protein patterns for guidance of neurites from cultured adult mouse dorsal root ganglia (DRG). The microdispenser is a micromachined silicon device that ejects 100 picolitre droplets and has the ability to position the droplets with a precision of 6-8 mu m. Laminin and bovine serum albumin (BSA) was used to create adhesive and non-adhesive protein lines on polystyrene surfaces (cell culture dishes). Whole-mounted DRGs were then positioned close to the patterns and neurite outgrowth was monitored. The neurites preferred to grow on laminin lines as compared to the unpatterned plastic. When patterns were made from BSA the neurites preferred to grow in between the lines on the unpatterned plastic surface. We conclude that microdispensing can be used for guidance of sensory neurites. The advantages of microdispensing is that it is fast, flexible, allows deposition of different protein concentrations and enables patterning on delicate surfaces due to its non-contact mode of operation. It is conceivable that microdispensing can be utilized for the creation of protein patterns for guiding neurites to obtain in vitro neural networks, in tissue engineering or rapid screening for guiding proteins. (c) 2006 Elsevier Ltd. All rights reserved.
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| 10. |
- Johansson, Fredrik, et al.
(författare)
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Guidance of neurons on porous patterned silicon: is pore size important?
- 2005
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Ingår i: Physica Status Solidi. C, Current Topics in Solid State Physics. - : Wiley. - 1610-1634. ; 2:9, s. 3258-3262
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Tidskriftsartikel (refereegranskat)abstract
- The paper studies the conditions optimum for the proliferation of neural cells at the surface of porous silicon. The results of this study show that the best results are achieved with meso-porous silicon. Geometrical properties of the wafers are also important through charge distribution at mask edges, change of hydrophobicity, degree of oxidation, the release of adhesion proteins from regenerating axons, etc
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