Symposium 2018 ‘The Chemistry of Collaboration: A World to Live in’
Chairman of the Day
Prof. dr. Wesley R. Browne
- University of Groningen
- Associate Professor and Chair of Molecular Inorganic Chemistry
Prof. dr. Moniek Tromp (Stratingh Speaker)
- University of Groningen
- Professor of Materials Chemistry
Prof. dr. Sandra Van Vlierberghe
- Ghent University \ Vrije Universiteit Brussel
- Biomaterials & polymer chemistry
Prof. dr. Jonathan Nitschke
- University of Cambridge
- Inorganic materials & Supramolecular Chemistry
Dr. Oliver Thorn-Seshold
- Ludwig Maximilians University Munich
- Chemical Biology and Pharmaceutical Chemistry
Dr. ir. Diego Wever
- Royal Dutch Shell
- Polymer research chemist
Evelyn Ramforth, MSc., MBA.
- Springer Nature
- Product Manager
Probing Reactive Species – Application of Advanced X-ray Techniques
Chair of Materials Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands, firstname.lastname@example.org
Detailed information on the structural and electronic properties of a catalyst or material and how they change during reaction is required to understand their reaction mechanism and performance. An experimental technique that can provide structural as well as electronic analysis and that can be applied in situ/operando and in a time-resolved mode, is X-ray spectroscopy. Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy is powerful in determining the local structure of compounds including amorphous materials and solutions, since long-range order is not required. Combined X-ray Absorption and X-ray Emission spectroscopy (XAS and XES resp.) provides detailed insights in the electronic properties of a material. Detailed information about the materials in their dynamic chemical active environment can thus be obtained and structure/electronic – performance relationships and reaction mechanisms derived. A combination of spectroscopic techniques (e.g. UV-Vis, IR) gives complementary information about the system under investigation.
Over the last years, different approaches have been reported to allow operando time resolved XAS on catalytic systems, mostly solid-gas. Our group has developed stopped-flow methodologies allowing simultaneous time-resolved UV–Vis/XAS experimentation on liquid systems down to the millisecond (ms) time resolution . Low X-ray energy systems (light elements) or for low concentrated systems, longer XAS data acquisition times in fluorescence detection are required and therefore a stopped flow freeze-quench procedure has been developed . Pushing the time-resolution has been achieved by synchronizing the synchrotron bunches with an optical laser in order to perform fast pump-probe experiments  or micro-reactors for modulation excitation experiments .
Developments in XAS using new instrumentation and data acquisition methods while selecting specific X-ray energies provide this more detailed electronic information . High energy resolution XAS, XES and Resonant Inelastic X-ray Scattering (RIXS) provide very detailed electronic information on the systems under investigation. The secondary spectrometer design also opens up lab based spectrometer designs as will be demonstrated.
The methodologies and instrumentation have been developed and applied to a wealth of materials science, for homogeneous and heterogeneous catalysis to batteries and fuel cells as well as art objects. In this lecture, several examples will be given, providing insights in activated/reactive species and reaction mechanisms.
Unprecedented Biomedical Opportunities Offered by Hydrogels and 3D Printing
Sandra Van Vlierberghe
Biofabrication is a specific area within the field of tissue engineering which takes advantage of rapid manufacturing (RM) techniques to generate 3D structures which mimic the natural extracellular matrix (ECM). A popular material in this respect is gelatin, as it is a cost-effective collagen derivative, which is the major constituent of the natural ECM. The material is characterized by an upper critical solution temperature making the material soluble at physiological conditions.
To tackle this problem, the present work focusses on different gelatin functionalization strategies which enable covalent stabilization of 3D gelatin structures.
In a second part, synthetic acrylate-endcapped, urethane-based precursors will be discussed with exceptional solid state crosslinking behaviour compared to conventional hydrogels.1, 2
RESULTS AND DISCUSSION
The first modification consists of methacrylation of the primary amines present in gelatin type B using methacrylic anhydride to obtain gel-MOD. As a consequence, the material becomes (photo-) crosslinkable using a chain growth polymerization mechanism. As a result, both extrusion- (e.g. Bioplotting) as well as irradiation-based rapid manufacturing (RM) techniques (e.g. two-photon-polymerization or 2PP) can be applied for biofabrication. Despite the proven material track record in biofabrication, it exhibits limitations in terms of post-production swelling and mechanical properties. To overcome these limitations, additional crosslinkable methacrylates can be introduced by additional carboxylic acid modification of the glutamic and aspartic acid side chains in gel-MOD with aminoethyl methacrylate via conventional carbodiimide coupling chemistry (EDC/NHS) to generate gel-MOD-AEMA.3 As a result, more densely crosslinked hydrogels can be obtained with a low to fully absent swelling degree, making the material more suitable towards high resolution RM techniques including 2PP.
To further increase the gelatin versatility, a third modification strategy was pursued during which norbornene functionalities were introduced to the primary amines.4 These functionalities have a very interesting reactivity towards thiols, as they can be applied for very fast, “spring-loaded” orthogonal thiol-ene “photo-click” reactions. When using multivalent thiol crosslinkers, crosslinked hydrogels can be obtained using significantly shorter irradiation times and/or doses. All developed derivatives were characterized in depth for their material properties (NMR, rheology, swelling,…) as well as biocompatibility by monitoring the metabolic activity of L929 fibroblasts and MC3T3 osteoblasts seeded onto thin crosslinked films. The metabolic assay indicated no significant difference between the gelatin derivatives in terms of biocompatibility. Furthermore, proof of concept biofabrication experiments were performed. Micro-scaffolds were generated using 2PP which indicated superior processing capabilities for the gel-MOD-AEMA and gel-norbornene derivatives.
Chemistry is a valuable tool to tailor the properties of hydrogels towards processing while preserving the material biocompatibility.
Complex and responsive systems via subcomponent self-assembly
Jonathan R. Nitschke
The materials that we depend on rely upon ever-increasing structural complexity for their function. The use of chemical self-assembly as a synthetic technique can simplify materials preparation by shifting intellectual effort away from designing molecules, and towards the design of chemical systems that are capable of self-assembling in such a way as to express desired materials properties and functions. Below are shown the subcomponent precursors and structures of three of products that can form functional constituents of these systems (Figure 1).
Current challenges involve inducing multiple structures to form in parallel, such that they may act in concert to achieve a catalytic goal, our techniques allow entry into the emerging field of systems chemistry. Functional systems that we have recently developed include a fuel-controlled self-assembly process and a series of cages that can phase-segregate and transit between liquid phases.
Figure 1. FeII8 cubic cage 1, FeII tetrahedral cage 2, and electroluminescent
CuIn double-helical polymer 3
Photopharmaceuticals: reimagining medicinal chemistry to bridge between optics and biology
Oliver Thorn-Seshold, LMU Munich, Germany
Drug compounds that modulate protein function drove much of the “revolution” in biology and medicine in the 20th Century. But many of the most important proteins – actin, tubulin, topoisomerases, etc – play multiple roles simultaneously: including some that are critical for healthy cell/organism function, some that are required by pathologies, and others whose function or relevance is not even understood. Hitting all their biological roles indiscriminately by using classical drugs, is therefore not a promising method to properly understand them (or a “clean” method to treat them).
Yet light-responsive drugs – photopharmaceuticals – can deliver both spatial and temporal specificity of bioactivity, and therefore may resolve the complexities of addressing such complex protein targets. In the best case they can act as “chemical levers,” controlled on the one side by highly precise illuminations (delivered by optical microscopes), and acting on the other side by binding potently to their protein targets. As they do not require genetic manipulation of proteins in order to work, they offer to be useful not only in research settings but even in disease therapy in patients.
However, there are still many challenges facing the concept of photopharmacology. This talk will use a case study of light-controlled microtubule inhibitors to highlight both scientific and “sociological” challenges of collaborating to bridge some of the gaps – of methodology, expectations, and even vocabulary – in order to connect the dots from optics, photochemistry, and medicinal chemistry (A), through cell biology (B-C) and biomedicine (D) towards pharmaceutical translation.
Future energy carriers
The world must find ways to meet the rising energy demand while reducing global greenhouse gas emissions to limit the effects of climate change. The historic Paris Agreement adopted by 195 countries in late 2015, and expected to be ratified over the coming year, established a goal to limit the global temperature rise this century to well below 2°C. This reinforces the need to shift our existing energy system to a system based on energy sources that are lower-carbon. It requires a huge undertaking – a global energy transition involves producing and consuming energy in a different way.
A successful energy transition requires substantial investment across all energy sources, including oil and gas production, to meet a growing demand for energy. Despite the tremendous progress in new energy technologies, we still do not have a comprehensive solution for a future energy carrier which is low cost, abundant, dense, clean and safe. Current options such as solar PV, wind, bio-mass, 1G/2G bio-fuels or hydrogen – while having significant commercial potential due to climate change concerns – still face significant compromises preventing them to be the ubiquitous, low-cost back-bone of the future energy system.
Advancing my research using authoritative data sets
Exceptional materials science research goes hand in hand with access to exceptional data. The elements of data integrity, accessibility, usability becomes increasingly complex with large amount of materials science data available. Materials scientists find it challenging to search structured datasets (crystal structures, phase diagrams, thermophysical, mechanical, polymer property data etc.) across disciplines in a centralized space. This interactive session will cover ways to find materials’ properties data efficiently using SpringerMaterials.