liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Conjugated Polymers, Amyloid Detection and Assembly of Biomolecular Nanowires
Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The research field of conjugated polymers has grown due to the optical and electronic properties of the material, useful in applications such as solar cells and printed electronics, but also in biosensors and for interactions with biomolecules. In this thesis conjugated polymers have been used in two related topics; to detect conformational changes in proteins and to assemble the polymers with biomolecules into nanowires.

Within biosensing, conjugated polymers have been used for detection of a wide range of biological events, such as DNA hybridization or enzymatic activity, utilizing both electronic and optical changes in the polymer. Here the focus has been to use the polymers as optical probes to discriminate between native and misfolded protein, as well as to follow the misfolding processes in vitro. The understanding and detection of protein misfolding, for example amyloid fibril formation, is a topic of growing importance. The misfolding process is strongly associated with several devastating diseases such as Alzheimer’s disease, Parkinson’s disease and Bovine Spongiform Encephalopathy (BSE). We have developed detection schemes for discrimination between proteins in the native or amyloid fibril state based on luminescent polythiophene derivatives. Through a synthesis strategy based on polymerization of trimer blocks rather than of monomers, polythiophene derivatives with higher optical signal specificity for amyloid-like fibrils were obtained.

Self-assembly of nanowires containing conjugated polymers is a route to generate structures of unique opto-electrical characteristics without the need for tedious topdown processes. Biomolecules can have nanowire geometries of extraordinary aspect ratio and functionalities. The DNA molecule is the most well known and exploited of these. In this thesis work the more stable amyloid fibril has been used as a template to organize conjugated polymers. Luminescent, semi-conducting, conjugated polymers have been incorporated in and assembled onto amyloid fibrils. Using luminescence quenching we have demonstrated that the conjugated material can retain the electro-activity after the incorporation process. Furthermore, the amyloid fibril/conjugated polymer hybrid structures can be organized on surfaces by the means of molecular combing and soft lithography.

In the process of generating self-assembled biomolecular nanowires functionalized with conjugated polymers, we have shown a new synthesis strategy for a water-soluble highly conducting polythiophene derivative. This material, PEDOT-S, has shown affinity for amyloid fibrils, but can also be very useful in conventional opto-electronic polymer-based devices.

Place, publisher, year, edition, pages
Institutionen för fysik, kemi och biologi , 2007.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1117
Keyword [en]
Conjugated Polymers, Amyloid Fibrils, Nanowires, Self-Assembly, Sensor, Amyloid Detection
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:liu:diva-9577ISBN: 978-91-85831-42-5 (print)OAI: oai:DiVA.org:liu-9577DiVA: diva2:23998
Public defence
2007-09-04, Planck, Physics Building, Linköping University, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2007-10-12 Created: 2007-10-12 Last updated: 2009-04-29
List of papers
1. Synthesis of a regioregular zwitterionic conjugated oligoelectrolyte, usable as an optical probe for detection of amyloid fibril formation at acidic pH
Open this publication in new window or tab >>Synthesis of a regioregular zwitterionic conjugated oligoelectrolyte, usable as an optical probe for detection of amyloid fibril formation at acidic pH
Show others...
2005 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, Vol. 127, no 7, 2317-2323 p.Article in journal (Refereed) Published
Abstract [en]

Changes of the optical properties of conjugated polyelectrolytes have been utilized to monitor noncovalent interactions between biomolecules and the conjugated polyelectrolytes in sensor applications. A regioregular, zwitterionic conjugated oligoelectrolyte was synthesized in order to create a probe with a defined set of optical properties and hereby facilitate interpretation of biomolecule−oligoelectrolyte interactions. The synthesized oligoelectrolyte was used at acidic pH as a novel optical probe to detect amyloid fibril formation of bovine insulin and chicken lysozyme. Interaction of the probe with formed amyloid fibrils results in changes of the geometry and the electronic structure of the oligoelectrolyte chains, which were monitored with absorption and emission spectroscopy.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-14598 (URN)10.1021/ja045835e (DOI)
Available from: 2007-10-12 Created: 2007-10-12 Last updated: 2014-04-08
2. Conjugated polyelectrolytes: conformation-sensitive optical probes for detection of amyloid fibril formation
Open this publication in new window or tab >>Conjugated polyelectrolytes: conformation-sensitive optical probes for detection of amyloid fibril formation
2005 (English)In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 44, no 10, 3718-3724 p.Article in journal (Refereed) Published
Abstract [en]

The in vivo deposition of amyloid fibrils is a hallmark of many devastating diseases known as the amyloidoses. Amyloid formation in vitro may also complicate production of proteins in the biotechnology industry. Simple, sensitive, and versatile tools that detect the fibrillar conformation of amyloidogenic proteins are thus of great importance. We have developed a negatively charged conjugated polyelectrolyte that displays different characteristic optical changes, detected visually or by absorption and emission, depending on whether the protein with which it forms a complex is in its native state or amyloid fibril conformation. This simple, rapid, and novel methodology was applied here to two amyloidogenic proteins, insulin and lysozyme, and its validity for detection of their fibrillar conformation was verified by currently used methods such as circular dichroism, transmission electron microscopy, and Congo red absorption.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-14599 (URN)10.1021/bi047402u (DOI)
Available from: 2007-10-12 Created: 2007-10-12 Last updated: 2014-04-08
3. Studies of luminescent conjugated polythiophene derivatives-Enhanced spectral discrimination of protein conformational states
Open this publication in new window or tab >>Studies of luminescent conjugated polythiophene derivatives-Enhanced spectral discrimination of protein conformational states
Show others...
2007 (English)In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 18, no 6, 1860-1868 p.Article in journal (Refereed) Published
Abstract [en]

Improved probes for amyloid fibril formation are advantageous for the early detection and better understanding of this disease-associated process. Here, we report a comparative study of eight luminescent conjugated polythiophene derivates (LCPs) and their discrimination of a protein (insulin) in the native or amyloid-like fibrillar state. For two of the LCPs, the synthesis is reported. Compared to their monomer-based analogues, trimer-based LCPs showed significantly better optical signal specificity for amyloid-like fibrils, seen from increased quantum yield and spectral shift. The trimer-based LCPs alone were highly quenched and showed little interaction with native insulin, as seen from analytical ultracentrifugation and insignificant spectral differences from the trimer-based LCP in buffered and native protein solution. Hence, the trimer-based LCPs showed enhanced discrimination between the amyloid-like fibrillar state and the corresponding native protein.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-14600 (URN)10.1021/bc700180g (DOI)
Available from: 2007-10-12 Created: 2007-10-12 Last updated: 2014-04-08
4. Electroactive luminescent self-assembled bio-organic nanowires: Integration of semiconducting oligoelectrolytes within amyloidogenic proteins
Open this publication in new window or tab >>Electroactive luminescent self-assembled bio-organic nanowires: Integration of semiconducting oligoelectrolytes within amyloidogenic proteins
Show others...
2005 (English)In: Advanced Materials, ISSN 0935-9648, Vol. 17, no 12, 1466-1471 p.Article in journal (Refereed) Published
Keyword
Biomaterials, Luminescence, Nanowires, Peptides, Poly(3, 4-ethylenedioxythiophene) (PEDOT), Self-assembly
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-14601 (URN)10.1002/adma.200500183 (DOI)
Available from: 2007-10-12 Created: 2007-10-12 Last updated: 2014-04-08
5. Alignment of a conjugated polymer onto amyloid-like protein fibrils
Open this publication in new window or tab >>Alignment of a conjugated polymer onto amyloid-like protein fibrils
Show others...
2007 (English)In: Small, ISSN 1613-6810, Vol. 3, no 2, 318-325 p.Article in journal (Refereed) Published
Abstract [en]

The amyloid-like fibril is a biomolecular nanowire template of very high stability. Here we describe the coordination of a conjugated polyelectrolyte, poly(thiophene acetic acid) (PTAA), to bovine insulin fibrils with widths of <10 nm and lengths of up to more than 10 m. Fibrils complexed with PTAA are aligned on surfaces through molecular combing and transfer printing. Single-molecule spectroscopy techniques are applied to chart spectral variation in the emission of these wires. When these results are combined with analysis of the polarization of the emitted light, we can conclude that the polymer chains are preferentially aligned along the fibrillar axis.

Keyword
fibrils, nanowires, polymers, self-assembly, template synthesis
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-14602 (URN)10.1002/smll.200600377 (DOI)
Available from: 2007-10-12 Created: 2007-10-12 Last updated: 2009-04-29
6. Decoration of amyloid fibrils with luminescent conjugated polymers
Open this publication in new window or tab >>Decoration of amyloid fibrils with luminescent conjugated polymers
Show others...
2008 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 18, no 1, 126-132 p.Article in journal (Refereed) Published
Abstract [en]

In this work we report the coating of a biological template with a polar, but uncharged, luminescent conjugated polymer, soluble in organic solvents but not in water, to produce a nanowire. Amyloid fibrils from bovine insulin were decorated with an alternating polyfluorene derivative. Decorated fibrils were partially aligned on hydrophobic surfaces as separate and bundled fibrils, by means of molecular combing. The single molecule spectroscopy technique utilizing excitation by rotating linearly polarized light and fluorescence detection through a rotating polarizer showed a high degree of anisotropy of the polymer chains on the individual fibrils. The high degree of polarization indicated highly oriented polymer chains with the preferential orientation of the polymer backbone along the fibrils. The anisotropy ratios are comparable with those of well-oriented polymer chains in films. © The Royal Society of Chemistry.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-14603 (URN)10.1039/b712829k (DOI)000251580400016 ()
Available from: 2007-10-12 Created: 2007-10-12 Last updated: 2010-04-26
7. Iron Catalyzed Polymerization of Alkoxysulfonate-Functionalized EDOT gives
Open this publication in new window or tab >>Iron Catalyzed Polymerization of Alkoxysulfonate-Functionalized EDOT gives
Show others...
2007 (English)In: Chemistry of Materials, ISSN 0897-4756Article in journal (Refereed) Submitted
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-14604 (URN)
Available from: 2007-10-12 Created: 2007-10-12

Open Access in DiVA

cover(538 kB)112 downloads
File information
File name COVER01.pdfFile size 538 kBChecksum SHA-1
00026d9efd17ed2e5d1b58efaaffb16c0a7d00f74ec7f498724677e218df91d577db3860
Type coverMimetype application/pdf
errata(10 kB)75 downloads
File information
File name ERRATA01.pdfFile size 10 kBChecksum SHA-1
e49a344dadf5314d62163cd69b259ddcdb6fdfb980537341cf4e142d54f6c8c0903ee68b
Type errataMimetype application/pdf
fulltext(1315 kB)4290 downloads
File information
File name FULLTEXT01.pdfFile size 1315 kBChecksum SHA-1
8603381c543b0b356ca054a7664f0c7a7575c8746d22dec1b5543a030169f49ca79c604f
Type fulltextMimetype application/pdf

Authority records BETA

Herland, Anna

Search in DiVA

By author/editor
Herland, Anna
By organisation
Biomolecular and Organic Electronics The Institute of Technology
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 4290 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1913 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf