Project

Back to overview

From DNA-Assembled Oligochromophores to Supramolecular Polymers: Aromatic Oligophosphates as Versatile Building Blocks for Functional Materials

English title From DNA-Assembled Oligochromophores to Supramolecular Polymers: Aromatic Oligophosphates as Versatile Building Blocks for Functional Materials
Applicant Häner Robert
Number 169030
Funding scheme Project funding (Div. I-III)
Research institution Departement für Chemie und Biochemie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Organic Chemistry
Start/End 01.01.2017 - 30.09.2019
Approved amount 600'000.00
Show all

Keywords (6)

DNA; supramolecular polymers; light harvesting systems; energy transfer; 2D polymers; chromophore

Lay Summary (German)

Lead
Desoxyribonukleinsäure (DNA) dient als molekulares Gerüst für die Herstellung von Strukturen im Nanometerbereich. Die starre Struktur der Doppelhelix erlaubt es, funktionelle Moleküle in präzis definierter Geometrie anzuordnen. Im vorliegenden Projekt werden einerseits DNA-basierte Farbstoff-Aggregate hergestellt und untersucht. Andererseits dient die DNA Doppelhelix als Leitmotiv für die Herstellung von 1- und 2-dimensionalen Polymeren. Die Bausteine dieser Polymere sind, wie in der DNA, über anionische Phosphodiester-Brücken verknüpft. Die Kombination von negativer Ladung und aromatischen Chromophoren gewährleistet einerseits eine gute Löslichkeit in Wasser und erlaubt gleichzeitig die effiziente Bildung von Aggregaten durch aromatische Molekülstapelung.
Lay summary

Hintergrund: Die präzise Anordnung von Einzelmolekülen zu einem grösseren Verbund wird aufgrund der vorgegebenen molekularen Struktur der DNA-Doppelhelix ermöglicht. Dadurch lassen sich die Eigenschaften von Multi-Chromophoren studieren, die auf andere Weise nur schwer oder gar nicht zugänglich sind. Auf diese Weise gewonnene Erkenntnisse werden in einem weiteren Schritt dazu verwendet, entsprechende Chromophor-Aggregate ohne DNA-Gerüst herzustellen. Insbesondere lassen sich so Polymere mit speziellen optischen und elektronischen Eigenschaften synthetisieren.

Ziele: Basierend auf den Erkenntnissen, die wir mit der Untersuchung von DNA-Farbstoff-Konjugaten gewonnen haben, werden 1- und 2-dimensionale Polymere mit speziellen strukturellen und elektronischen Eigenschaften hergestellt. Von besonderer Bedeutung sind hierbei Polymere mit lichtsammelnden Eigenschaften.

Bedeutung: Die Verwendung der DNA als intelligentem, molekularen Baugerüst erlaubt die präzise Anordnung von funktionellen Molekülen und kann dadurch Zugang zu neuartigen Materialien mit speziellen elektronischen und physikalischen Eigenschaften verschaffen. Solche Materialien können in der Zukunft zur Energiegewinnung eingesetzt werden, z.B.  in Form von lichtsammelnden Komplexen. Andererseits können sie auch Verwendung finden in optischen Geräten, in Photozellen oder in diagnostischen Hilfsmitteln zur frühen Erkennung von Infektions- oder Erbkrankheiten.
Direct link to Lay Summary Last update: 23.09.2016

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
149148 DNA-based Oligomeric and Polymeric Functional Materials 01.10.2013 Project funding (Div. I-III)

Abstract

The construction and study of novel types of one- and two-dimensional supramolecular polymers from short, DNA-inspired oligomers is proposed. Phosphodiester-linked aromatic oligomers (oligoarenotides) built from various polyaromatic building blocks, such as phenanthrene, pyrene or chrysene, exhibit surprising structural and functional diversity in an aqueous environment. Self-assembly leads to formation of supramolecular structures, including fibres, nanosheets and nanotubes. The resultant polychromophores will be studied for their electronic and structural properties.A major effort will be dedicated to deepen our understanding of the supramolecular polymerization of oligoarenotides. Past studies showed that the morphology of the formed supramolecular polymers is not only influenced by the aromatic residues, but, to a large extent, also by the connecting linkers. Important factors include the geometry (i.e., site of attachment to the aromatic core), the length and the chemical nature (e.g., carboxamide- vs. alkynyl-substitution). Closely related to these activities are efforts aiming at the covalent linkage of assembled oligomers, which would allow the conversion of supramolecular polymers to covalent polymers. Different strategies (photodimerization of anthracene-containing hexagonal DNA networks; disulfide formation of linear and two-dimensional supramolecular polymers) will be pursued. The construction and study of light-harvesting supramolecular polymers will also be of primary interest. We plan to extend our studies of one- and two-dimensional polymers to other types of chromophores, such as cyanines and porphyrins. Additionally, we will start to explore oligoarenotide-based supramolecular polymers as biomimetic and biocompatible materials. These efforts will include probing the interaction of polymers with cationic protein complexes, especially histones, as well as the use of silanized polymers for cellular applications (cellular imaging, in collaboration with Prof. A. Stocker at our department).Once established, synthesis of oligoarenotides and subsequent formation of supramolecular polymers comes as a series of straightforward steps. However, the underlying principles (aggregation behavior, exciton formation, energy transfer) were all established in preceding studies with DNA-assembled oligochromophores. This demonstrates the value of the DNA duplex as a supramolecular scaffold for the precise arrangement of functional compounds. Therefore, we will continue and extend our work in the area of DNA-controlled assembly of chromophores. In particular, we will continue studying the process of excitation energy transfer in DNA-assembled polychromophore systems in collaboration with Prof. T. Feurer and Prof. A. Cannizzo, Institute of Applied Physics, UniBE (NCCR Molecular Ultrafast Science and Technology), as well as PD Dr. M. Calame (Department of Physics & Swiss Nanoscience Institute, University of Basel).Another important aspect is the chemical synthesis of additional types of chromophoric building blocks. While concentrating on the investigation of the well-established polyaromatic hydrocarbons pyrene and phenanthrene, we will also synthesize and test the analogous phenanthroline building blocks. Of major importance in this regard will be the compatibility of the new derivatives with oligonucleotide synthesis, their ability to support the formation of multi-stranded hybrids, and, most importantly, the changes in electronic properties upon formation of multi-chromophoric aggregates. Although not explicitly mentioned in the detailed research plan, we are continuing our efforts with porphyrins and chrysene. Electronic coupling, which is present between chromophores in oligomers, is under investigation in collaboration with Prof. G. Calzaferri at our department.
-