| 1. |
- Asplund, Maria, et al.
(författare)
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Construction of wire electrodesand 3D woven logicas a potential technology forneuroprosthetic implants
- 2008
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Ingår i: IEEE Transactions on Biomedical Engineering. - 0018-9294 .- 1558-2531.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- New strategies to improve neuron coupling to neuroelectronic implants are needed. In particular, tomaintain functional coupling between implant and neurons, foreign body response like encapsulation must meminimized. Apart from modifying materials to mitigate encapsulation it has been shown that with extremely thinstructures, encapsulation will be less pronounced. We here utilize wire electrochemical transistors (WECTs) usingconducting polymer coated fibers. Monofilaments down to 10 μm can be successfully coated and weaved intocomplex networks with built in logic functions, so called textile logic. Such systems can control signal patterns at alarge number of electrode terminals from a few addressing fibres. Not only is fibre size in the range where lessencapsulation is expected but textiles are known to make successful implants because of their soft and flexiblemechanical properties. Further, textile fabrication provides versatility and even three dimensional networks arepossible. Three possible architectures for neuroelectronic systems are discussed. WECTs are sensitive to dehydrationand materials for better durability or improved encapsulation is needed for stable performance in biologicalenvironments.
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| 2. |
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| 3. |
- Asplund, Maria, 1978-, et al.
(författare)
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Wire electronics and woven logic, as a potential technology for neuroelectronic implants
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Annan publikation (populärvet., debatt m.m.)abstract
- New strategies to improve neuron coupling to neuroelectronic implants are needed. In particular, to maintain functional coupling between implant and neurons, foreign body response like encapsulation must me minimized. Apart from modifying materials to mitigate encapsulation it has been shown that with extremely thin structures, encapsulation will be less pronounced. We here utilize wire electrochemical transistors (WECTs) using conducting polymer coated fibers. Monofilaments down to 10 μm can be successfully coated and weaved into complex networks with built in logic functions, so called textile logic. Such systems can control signal patterns at a large number of electrode terminals from a few addressing fibres. Not only is fibre size in the range where less encapsulation is expected but textiles are known to make successful implants because of their soft and flexible mechanical properties. Further, textile fabrication provides versatility and even three dimensional networks are possible. Three possible architectures for neuroelectronic systems are discussed. WECTs are sensitive to dehydration and materials for better durability or improved encapsulation is needed for stable performance in biological environments.
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| 4. |
- Björk, Per, et al.
(författare)
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Biomolecular nanowires decorated by organic electronic polymers
- 2010
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Ingår i: JOURNAL OF MATERIALS CHEMISTRY. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 20:12, s. 2269-2276
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the shaping and forming of organic electronic polymers into designer nanostructures using biomacromolecules. In order to create nanowires, nanohelixes and assemblies of these, we coordinate semiconducting or metallic polymers to biomolecular polymers in the form of DNA and misfolded proteins. Optoelectronic and electrochemical devices utilizing these shaped materials are discussed.
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| 5. |
- Hamedi, Mahiar, et al.
(författare)
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Bridging Dimensions in Organic Electronics : Assembly of Electroactive Polymer Nanodevices from Fluids
- 2009
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 9:2, s. 631-635
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Tidskriftsartikel (refereegranskat)abstract
- Processing and patterning of electroactive materials from solvents is a hallmark of flexible organic electronics,(1) and commercial applications based on these properties are now emerging. Printing and ink-jetting are today preferred technologies for patterning, but these limit the formation of nanodevices, as they give structures way above the micrometer lateral dimension. There is therefore a great need for cheap, large area patterning of nanodevices and methods for top-down registration of these. Here we demonstrate large area patterning of connected micro/nanolines and nanotransistors from the conducting polymer PEDOT, assembled from fluids. We thereby simultaneously solve problems of large area nanopatterning, and nanoregistration.
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| 6. |
- Hamedi, Mahiar, et al.
(författare)
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Electrochemical Devices Made from Conducting Nanowire Networks Self-Assembled from Amyloid Fibrils and Alkoxysulfonate PEDOT
- 2008
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 8:6, s. 1736-1740
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Tidskriftsartikel (refereegranskat)abstract
- Proteins offer an almost infinite number of functions and geometries for building nanostructures. Here we have focused on amyloid fibrillar proteins as a nanowire template and shown that these fibrils can be coated with the highly conducting polymer alkoxysulfonate PEDOT through molecular self-assembly in water. Transmission electron microscopy and atomic force microscopy show that the coated fibers have a diameter around 15 nm and a length/thickness aspect ratio >1:1000 . We have further shown that networks of the conducting nanowires are electrically and electrochemically active by constructing fully functional electrochemical transistors with nanowire networks, operating at low voltages between 0 and 0.5 V.
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| 7. |
- Hamedi, Mahiar, et al.
(författare)
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Electronic Polymers and DNA Self-assembled in Nanowire Transistors
- 2013
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Ingår i: Small. - : Wiley-VCH Verlag Berlin. - 1613-6810 .- 1613-6829. ; 9:3, s. 363-368
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Tidskriftsartikel (refereegranskat)abstract
- In this study the fully acidic form of PEDOT-S was used for the purpose of self-assembly onto DNA. We have previously shown that PEDOT-S is a short polymer that is self-doped with !1/3 of the sulfonate side groups acting as the self-doping sites (see supporting info.). The remaining sulfonate groups contribute to a net anionic charge, and a water-soluble polymer, with an intrinsic bulk conductivity of around 30 S/cm. It has been shown that PEDOT-S can bind to oppositely charged cationic amyloid protein structures in water and form conducting nano fibrillar networks, and it has also been shown to form hybrid structures with synthetic peptides, and gold nanoparticles.
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| 8. |
- Hamedi, Mahiar, et al.
(författare)
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Fiber-Embedded Electrolyte-Gated Field-Effect Transistors for e-Textiles
- 2009
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 21:5, s. 573-577
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Tidskriftsartikel (refereegranskat)abstract
- Electrolyte-gate organic field-effect transistors embedded at the junction of textile microfibers are demonstrated. The fiber transistor operates below I V and delivers large current densities. The transience of the organic thin-film transistors current and the impedance spectroscopy measurements reveal that the channel is formed in two steps.
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| 9. |
- Hamedi, Mahiar
(författare)
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Organic electronics on micro and nano fibers : from e-textiles to biomolecular nanoelectronics
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Research in the field of conjugated polymers (CPs) has led to the emergence of a number of interesting research areas and commercial applications, including solar cells, flexible displays, printed electronics, biosensors, e-textiles and more.Some of the advantages of organic electronics materials, as compared to their inorganic counterparts, include high elasticity, and mechanical flexibility, which allows for a natural integration of CPs into fabrics, making them ideal for e-texile. In this thesis, a novel approach for creating transistors is presented, through the construction of electrolyte gated transistors, directly embedded on functional textile fibers. Furthermore theoretical and experimental results of the integration of functional woven devices based on these transistors are shown. The realization of woven digital logic and design schemes for devices that can be placed inside living tissue, for applications such as neural communication, are demonstrated.Reducing feature sizes in organic electronics is necessity just as in conventional microelectronics, where Moore's law has been the most impressive demonstration of this over the past decades. Here the scheme of self-assembly (SA) of biomolecular/CP hybrid nano-structures is used for creating nano electronics. It is demonstrated that proteins in the form of amyloid fibrils can be coated with the highly conducting polythiophene derivative (PEDOT-S) through molecular self-assembly in water, to form conducting nanowire networks and nanodevices at molecular dimensions. In a second SA scheme, large area patterning of connected micro-nano lines and nano transistors from the conducting polymer PEDOT-S is demonstrated through assembly of these from fluids using soft lithography. Thereby the problems of large area nano patterning, and nano registration are solved for organic electronics. The construction of functional nanoscopic materials and components through molecular self-assembly has the potential to deliver totally new concepts, and may eventually allow cheap mass production of complex three dimensional nano electronic materials and devices.
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| 10. |
- Hamedi, Mahiar, et al.
(författare)
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Towards woven logic from organic electronic fibres
- 2007
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-1122 .- 1476-4660. ; 6:5, s. 357-362
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Tidskriftsartikel (refereegranskat)abstract
- The use of organic polymers for electronic functions is mainly motivated by the low-end applications, where low cost rather than advanced performance is a driving force. Materials and processing methods must allow for cheap production. Printing of electronics using inkjets1 or classical printing methods has considerable potential to deliver this. Another technology that has been around for millennia is weaving using fibres. Integration of electronic functions within fabrics, with production methods fully compatible with textiles, is therefore of current interest, to enhance performance and extend functions of textiles2. Standard polymer field-effect transistors require well defined insulator thickness and high voltage3, so they have limited suitability for electronic textiles. Here we report a novel approach through the construction of wire electrochemical transistor (WECT) devices, and show that textile monofilaments with 10–100 m diameters can be coated with continuous thin films of the conducting polythiophene poly(3,4-ethylenedioxythiophene), and used to create micro-scale WECTs on single fibres. We also demonstrate inverters and multiplexers for digital logic. This opens an avenue for three-dimensional polymer micro-electronics, where large-scale circuits can be designed and integrated directly into the three-dimensional structure of woven fibres.
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