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Research

Metal-Mediated Self-Assembly of Nano-Cages and DNA G-Quadruplexes

Our work is motivated by the structural and functional complexity we find in nature’s biochemical machinery. We take delight in designing and constructing artificial devices, aggregates and complex systems on a molecular scale. We create functional molecules and supramolecular assemblies by a bottom-up assembly which serve as foundation for new diagnostic tools, selective reagents and stimuli-responsive materials.

We are thrilled by the progress in self-assembly of nanostructures under thermodynamic control, but most known architectures consist of only few different components. How can we add even higher levels of complexity through smart combination of different building blocks, assembling in non-statistical manner and acting together to show emergent behavior?

Can we trigger state changes in self-assembled systems via stimuli-responsive elements, make them operate away from thermodynamic equilibrium, perform cascaded interconversions, transfer in­for­mation on the nanoscale, e.g. by propagating chirality via non-covalent interactions?

Will self-assembly strategies developed in our lab allow chromophores and redox centers to be positioned in space to control exciton and electron transfer processes?

Can we make artificial nanoscale objects interact with biomolecules and serve as diagnostic tools or mediators for biochemical processes?

Can bio-artificial hybrid compounds exploit the benefits from both the natural world as well as man-made technology? In this sense, can the biologically proven concept of selective catalysis in a nano-confined metallo-protein pocket be transferred to artificial host systems or tailor-made oligonucleotide folds equipped with metal-binding sites?

Metallo-supramolecular assemblies form the basis of our research. We have developed a large family of self-assembled coordination cages, including hosts with a range of cavity sizes and shapes, mechanically interlocked systems showing allosteric guest binding behavior and chiral recognition environments. Our current focus is set on dye-based assemblies, light-switchable and -harvesting systems and catalytically active architectures.

Our specialty are heteroleptic assemblies, formed under integrative self-sorting conditions along non-statistical routes. They form the basis for multifunctional nanostructures consisting of a set of distinguishable components, combined in a modular and synthetically simple way. Examples below show how we implement photoswitches as chiral in­for­mation carriers, create new amphiphiles from anisotropic coordination cages and use bowl-shaped hosts as supramolecular protecting groups to control the functionalization of fullerenes.

A further section of our group synthesizes ligand-modified DNA G-quadruplexes able to carry transition metal ions in their loop regions to serve as tunable enantioselective catalysts, switchable binding systems and highly rigid EPR labels. Our studies on the chiroptical recognition of DNA secondary structures by dye-functionalized helicates bridge both of these fields.

Our lab combines a profound expertise in the synthesis of functional organic building blocks with a toolbox of metal-mediated assembly strategies, tailored application of non-covalent interactions and implementation of stimuli-responsive elements reacting to light or chemical inputs. Besides multistep organic synthesis, coordination chemistry, automated solid-phase preparation of DNA and modern purification methods (recycling GPC, chiral HPLC), we employ a wide range of analytical tools to characterize the supramolecular systems, including dynamic NMR, ion mobility mass spectrometry, single crystal X-ray diffraction, isothermal titration calorimetry, chiroptical methods (circular dichroism, circularly polarized luminescence). We use computational methods to design new assemblies, compare energies of isomeric structures, determine gas phase collisional cross sections and various spectroscopic properties.

The fruits of our work are meant to contribute fundamental knowledge to the fields of non-covalent interactions (interplay of effects in complex systems, temporal development under stimuli-response, competitive binding), multi-component self-assembly (entropy and strain effects, solvation and templation, constitutional dynamic libraries) and DNA nanotechnology (metal-base pairing in non-duplex DNA systems, control over oligonucleotide topologies, rational enantioselective catalysis).

We further aim to demonstrate that increasing structural and functional complexity of supramolecular systems can be achieved based on rational design rather than serendipitous findings. Finally, concepts and compounds arising from our research are evaluated in target-oriented development rounds for exploring their application potential. Our short-term goals include the development of new reagents for fullerene chemistry, chiroptical and EPR probes for biopolymers as well as modular catalysts. On the long term, we see potential benefit for the fields of molecular biology, diagnostics, intelligent materials as well as molecular electronics and photovoltaics.

Find out more about our projects on the following page. The following shortcuts lead to our current focus areas.

Location & approach

The campus of TU Dort­mund University is located close to interstate junction Dort­mund West, where the Sauerlandlinie A 45 (Frankfurt-Dort­mund) crosses the Ruhrschnellweg B 1 / A 40. The best interstate exit to take from A 45 is "Dort­mund-Eichlinghofen" (closer to Campus Süd), and from B 1 / A 40 "Dort­mund-Dorstfeld" (closer to Campus Nord). Signs for the uni­ver­si­ty are located at both exits. Also, there is a new exit before you pass over the B 1-bridge leading into Dort­mund.

To get from Campus Nord to Campus Süd by car, there is the connection via Vogelpothsweg/Baroper Straße. We recommend you leave your car on one of the parking lots at Campus Nord and use the H-Bahn (suspended monorail system), which conveniently connects the two campuses.

TU Dort­mund University has its own train station ("Dort­mund Uni­ver­si­tät"). From there, suburban trains (S-Bahn) leave for Dort­mund main station ("Dort­mund Hauptbahnhof") and Düsseldorf main station via the "Düsseldorf Airport Train Station" (take S-Bahn number 1, which leaves every 20 or 30 minutes). The uni­ver­si­ty is easily reached from Bochum, Essen, Mülheim an der Ruhr and Duisburg.

You can also take the bus or subway train from Dort­mund city to the uni­ver­si­ty: From Dort­mund main station, you can take any train bound for the Station "Stadtgarten", usually lines U41, U45, U 47 and U49. At "Stadtgarten" you switch trains and get on line U42 towards "Hombruch". Look out for the Station "An der Palmweide". From the bus stop just across the road, busses bound for TU Dort­mund University leave every ten minutes (445, 447 and 462). Another option is to take the subway routes U41, U45, U47 and U49 from Dort­mund main station to the stop "Dort­mund Kampstraße". From there, take U43 or U44 to the stop "Dort­mund Wittener Straße". Switch to bus line 447 and get off at "Dort­mund Uni­ver­si­tät S".

The H-Bahn is one of the hallmarks of TU Dort­mund University. There are two stations on Campus Nord. One ("Dort­mund Uni­ver­si­tät S") is directly located at the suburban train stop, which connects the uni­ver­si­ty directly with the city of Dort­mund and the rest of the Ruhr Area. Also from this station, there are connections to the "Technologiepark" and (via Campus Süd) Eichlinghofen. The other station is located at the dining hall at Campus Nord and offers a direct connection to Campus Süd every five minutes.

The AirportExpress is a fast and convenient means of transport from Dort­mund Airport (DTM) to Dort­mund Central Station, taking you there in little more than 20 minutes. From Dort­mund Central Station, you can continue to the uni­ver­si­ty campus by interurban railway (S-Bahn). A larger range of in­ter­na­tio­nal flight connections is offered at Düsseldorf Airport (DUS), which is about 60 kilometres away and can be directly reached by S-Bahn from the uni­ver­si­ty station.

The facilities of TU Dort­mund University are spread over two campuses, the larger Campus North and the smaller Campus South. Additionally, some areas of the uni­ver­si­ty are located in the adjacent "Technologiepark".

Site Map of TU Dort­mund University (Second Page in English).