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Dynamic Molecular Nanostructures

Final Report Summary - DYNAMOL (Dynamic Molecular Nanostructures)

Research within the ITN DYNAMOL is related to the cutting-edge field of nanotechnology and nano-sized materials, one of the fastest growing areas in modern chemistry and applications. This ITN tackles the preparation of functional molecular nanostructures from a novel chemical bottom-up approach using self-assembly processes. The synthetic strategies rely predominantly on dynamic covalent interactions between molecular building blocks under thermodynamic control, whose reversibility allows deliberate control over dynamic equilibria to generate molecular nanostructures of defined architecture and/or properties. The main objective of this ITN is to train a new generation of highly skilled chemists in this area while gaining profound new knowledge about strategies to control dynamic reactions and their use for the synthesis of molecular nanostructures. We aim to: develop a toolbox that allows deliberate construction of organic nanostructures on different supports, as discrete molecular species, or as the basis for new materials; identify and develop new applications of molecular nanostructures in such diverse fields as information processing (sensors, Boolean logic gates), controlled capture or release of reactive molecules, gas storage, microfluidic systems, or materials science. With this aim, DYNAMOL joins 9 academic partners, all leading scientists in the area of supramolecular and dynamic covalent chemistry, and 3 full and associated industrial partners, serving the critical role of bridging fundamental science with application and commercialisation of the results.

The DYNAMOL website is running and up to date, containing general information about the ITN, its organization and events. “Dropbox” is used as password protected intranet accessible to all members to share documents with training purposes.
Address of the project public website: “www.dynamol.ch.cam.ac.uk”

The training programme was designed to produce highly skilled researchers, who are not only highly knowledgeable in the area of nanotechnology, but also have been educated to be creative and innovative scientists. Six workshops and a summer school were part of the network-wide training programme: Bordeaux (November 2011, 1st workshop/kick off meeting), Lausanne (March 2012, 2nd workshop), Israel (July 2012, 3rd workshop), Cambridge (October 2012, 4th workshop/Mid-term review meeting), Barcelona (April 2013, 5th workshop), Groningen (September 2013, joint summer school with the ReAd ITN) and Lyon (June 2014, 6th workshop). Invited experts delivered lectures on relevant areas to the Network and the fellows presented the results of their personal projects in the form of oral presentations. The fellows also gave poster presentations at the 3rd workshop in Israel as part of the Dwek Research School of Chemical Science symposium and at the 5th workshop in Barcelona in a joint poster session with the Institut de Bioenginyeria de Catalunya (IBEC) and Institut de Ciències de Materials de Barcelona (ICMAB). Four training courses were provided on key techniques in nanotechnology: Isothermal Titration Calorimetry (2nd workshop), X-ray Crystallography (4th workshop), Fundamentals of Nanotechnology (5th workshop) and NMR spectroscopy and Microscopy (summer school). In addition to the network-wide training programme, the fellows all received local training in complementary skills (language courses, specific skills courses), prepared periodic progress reports (also available to all Dynamol members in our intranet) and gave regular presentations in group meetings at their host institutions.

The specific scientific and technological objectives of the network’s programme were divided in four sub-programmes (SP): SP1 – Functional Nanoparticles: WP1 - “Template-directed Dynamic Surface Modification of Gold Nanoparticles” - RUG; WP2 - “Template-directed Thiol Exchange on Gold Nanoparticle Surfaces” - TU Kaiserslautern; WP3 - “Dynamic Ligand Exchange on Cyclodextrin Decorated Nanoparticles” - U Twente/Wageningen. SP2 - Boron-Based Nanostructures: WP4 - “Boron-based Cages and Polymers” - EPFL; WP5 - “Boron-based Dendrimers” - CAU – Kiel. SP3 – Dynamic Molecular Nanocages: WP6 - “Dynamic Nanocage Assembly” - UCAM; WP7 - “Guest Release Dynamics” - UCAM; WP8 - “Dynamic Foldamer Assembly” - UB; WP9 - “Assembly of Synthetic Capsids” - KTH. SP4 - Self-Assembled Molecular Materials: WP10 – “Self-Propagating Assembly of Molecular-based Materials” - Weizmann; WP11 – “Localised Surface Functionalisation within Microfluidic Channels” - Micronit; WP12 - “Supramolecular Chemistry and Macromolecular Crystallography” - Global Phasing.

Each sub-programme was further divided into three Phases: development of synthetic methodologies (Phase 1), nanostructure analysis (Phase 2) and nanostructure applications (Phase 3). In SP1, nanoparticle synthetic procedures were developed, dynamic reactions on nanoparticle surfaces were studied and the resulting functionalised nanoparticles were characterised by different techniques (transmission electron microscopy, dynamic light scattering and NMR spectroscopy). The application of these functionalised nanoparticles in the recognition of biomolecules, such as DNA, lectins and amino acids, was investigated and fluorescent assays were developed. In SP2, a number of boron-based ligands were prepared and exploited to synthesise nanocage structures at EPFL and self-assemble dendritic architectures at CAU-Kiel. In SP3, a variety of nanocages were prepared at UCAM and their host-guest properties were investigated. It was possible to modulate guest uptake and release within the cages exploiting cooperative effects. At KTH, a new family of dynamic, amphiphilic structures based on dendritic scaffolds was developed as synthetic capsids and the release of a probe within the capsid was achieved using a thermal stimulus or biocompatible ligand for competitive binding. At UB, a series of aromatic helical compounds was synthesized and the factors influencing the helical propensity of aromatic monomers were evaluated. In SP4, layer-by-layer deposition in combination with metal-ligand coordination was exploited at WIS to construct coordination polymer films with high redox stability and low switching time and solid-state electrochromic devices were fabricated. At Micronit, the goal of locally functionalizing a closed glass microfluidic channel was achieved through a variety of surface modification techniques and this methodology was applied to develop a novel supramolecular nanoparticle based biosensor with tunable sensitivity (nM to pM), in which the fabrication concept can be easily used in the detection of different proteases (focusing on blood clotting relevant enzymes). The generation of restraint dictionaries in SHELX syntax was implemented into the Grade program at Global Phasing and also made publicly available via the Grade Web Server at http://grade.globalphasing.org.
Therefore, all projects have successfully achieved the objectives set in Annex I for Phases 1, 2 and 3. This work has resulted in the publication of eighteen papers (two of them still in press), submission of another four papers and at least ten papers are currently in preparation to be submitted shortly.

Collaboration between partners and fellows was established through secondments with the timing arranged based on the research needs of the fellows. Synergy both within and between the research sub-programmes was achieved: the chlathrochelate complexes developed at EPFL were exploited to self-assemble dynamic dendrimers at Kiel and nanocages at UCAM; amide-branched dendrons prepared at KTH were combined with the core structures prepared at Kiel; DOSY NMR and TEM measurements were carried out at WU on nanoparticles prepared at TUKL. Opportunities for collaborations outside the network were also made possible through connections of network partners. Maria Oikonomou, ESR at Wageningen, was seconded to Marc-André Delsuc’s group (PI from the ReAd ITN) at NMRTEC in Strasbourg for training on advanced acquisition and processing of DOSY NMR spectra using DOSYMaxEnt. Julian Holstein, ER at Global Phasing, established a collaboration with Dr. Phil Pattison, from the EPFL Cubotron and senior scientist at ESRF beamline BM1A, during his secondment at EPFL in March 2013. Challenging supramolecular samples were provided by the Severin group, the measurements were performed by Dr. Pattison and the data processing and analysis was carried out at Global Phasing.

Nanotechnology is a research field that has gained significant attention recently, in part due to the numerous applications of nano-sized materials in everyday life. Despite the importance of this field in the development of new products, this is a subject that is not currently taught in great depth in universities. This network has educated and trained the next generation of chemical researchers in nanotechnology to ensure Europe remains competitive in this lucrative market. Furthermore, the results from the research have strengthened Europe’s innovation capacity in nanotechnology and there is the potential to exploit these results to develop commercial products.