| 1. |
- Björk, Per, et al.
(författare)
-
Oligothiophene Assemblies Defined by DNA Interaction : From Single Chains to Disordered Clusters
- 2009
-
Ingår i: SMALL. - : Wiley. - 1613-6810 .- 1613-6829. ; 5:1, s. 96-103
-
Tidskriftsartikel (refereegranskat)abstract
- The organization of conjugated polyelectrolytes (CPEs) interacting with biomolecules sets conditions for the biodetection of biological processes and identity, through the use of optical emission from the CPE. Herein, a well-defined CPE and its binding to DNA is studied. By using dynamic light scattering and circular dichroism spectroscopy, it is shown that the CPE forms a multimolecule ensemble in aqueous solution that is more than doubled it? size when interacting with a small DNA chain, while single chains are evident in ethanol. The related changes in the fluorescence spectra upon polymer aggregation are assigned to oscillator strength redistribution between vibronic transitions in weakly coupled H-aggregates. An enhanced single-molecule spectroscopy technique that allows full control of excitation and emission light polarization is applied to combed and decorated;,DNA chains. It is found that the organization of combed CPE-lambda DNA complexes (when dry on the surface) allows considerable variation of CPE distances and direction relative to the DNA chain. By analysis of the polarization data. energy transfer between the polymer chains in individual complexes is confirmed and their sizes estimated.
|
|
| 2. |
- Björk, Per, et al.
(författare)
-
Soft lithographic printing of patterns of stretched DNA and DNA/electronic polymer wires by surface-energy modification and transfer
- 2006
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 2:8-9, s. 1068-1074
-
Tidskriftsartikel (refereegranskat)abstract
- Aligned and stretched λ DNA is directed to specific locations on solid substrates. Surface-energy modification of glass substrates by using patterned polydimethylsiloxane (PDMS) stamps is used to direct DNA onto the surface-energy-modified micrometer-scale pattern through molecular combing. As an alternative, patterned and nonpatterned PDMS stamps modified with polymethylmethacrylate (PMMA) are utilized to direct the stretched DNA to the desired location and the results are compared. The DNA is elongated through molecular combing on the stamp and transfer printed onto the surfaces. PMMA-modified stamps show a more defined length of the stretched DNA, as compared to bare PDMS stamps. A combination of these two methods is also demonstrated. As an application example, transfer printing of DNA decorated with a semiconducting conjugated polyelectrolyte is shown. The resulting patterned localization of stretched DNA can be utilized for functional nanodevice structures, as well as for biological applications.
|
|
| 3. |
- Hamedi, Mahiar, et al.
(författare)
-
Electronic Polymers and DNA Self-assembled in Nanowire Transistors
- 2013
-
Ingår i: Small. - : Wiley-VCH Verlag Berlin. - 1613-6810 .- 1613-6829. ; 9:3, s. 363-368
-
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.
|
|
| 4. |
- Herland, Anna, et al.
(författare)
-
Alignment of a conjugated polymer onto amyloid-like protein fibrils
- 2007
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 3:2, s. 318-325
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
