Faculty of Chemistry


In 2014, the Collaborative Research Centre 1093, “Supramolecular Chemistry on Proteins”, was launched, which is coordinated and managed by our Faculty. In this CRC, working groups from Chemistry and Biology work together to develop chemical tools (called ligands) that bind themselves specifically to proteins and which can thereby influence their biological functions. For one thing, this requires a precise understanding of the structure and operation of the proteins in question – this is the area of expertise of those working in Biology. Based on this structural information, the chemists carefully design molecules that can bind themselves to specific parts of the proteins. The entire methodological range of modern chemistry (e.g. synthesis of natural product derivatives, solid-phase synthesis, combinatorial methods and polymer chemistry, to name just a few examples) is used to this end. The latter, combined with a thorough understanding of the molecular interactions that allow molecules to bind themselves to each other and the use of customized synthetic gripping tools, mean that efficient ligands can be developed that recognise specific individual proteins. The Essen-based chemists are recognised experts, both nationally and internationally, in the area of supramolecular chemistry, which this year incidentally was once again awarded the Nobel Prize in Chemistry, the last time being in 1987. Although CRC 1093 has only been running for just over two years, it has already generated a substantial amount of exciting and fascinating results. Multi-armed molecules have been identified from a combinatory library that enhance the interaction of the so-called 14-3-3 proteins with their natural binding partners (adaptor proteins such as cRaf or Tau) by up to two orders of magnitude. The molecular adhesives achieve this by using their multiple arms to simultaneously bind themselves both to the 14-3-3 protein and the adaptor protein, so that the two then stick together. As the 14-3-3 proteins are a very important class of proteins involved in many cell signalling processes, the chemists in Essen hope to also be able to precisely alter cellular functions with such molecules in the next step. Other work has shown that small molecular tweezers – a ring-shaped molecule – only surround certain selected groups like a napkin ring on the surface of a highly-complex protein machine. The scientists have even succeeded in recording the crystal structure, i.e. a kind of molecular photo, of such a complex – something rarely achieved elsewhere in the world.

Another large research group in which the Faculty of Chemistry plays a major role is the NRW Progress Group FUTURE WATER. Within this doctoral programme, supported between 2014 and 2018 by the Ministry of Innovation, Science and Research of North Rhine-Westphalia, research is carried out on sustainable urban water management under the leadership of the Faculty of Chemistry in a group that encompasses various scientific disciplines and industrial mentors. In addition to social, cultural, and scientific issues and regulatory aspects, the researchers focus on the assessment of the significance of transformation products for wastewater treatment and the role of viruses in waste water for long-term sustainable urban water management. The examination of water in the urban context is also making it clear that the systems and issues which are to be evaluated are becoming increasingly complex. The well-established analytical methods that have been known for decades now often reach their limits. For this reason, researchers working in analytical chemistry at our Faculty are, for example, attempting to refine traditional chromatographic techniques, so that complex samples can be divided into up to four independent property dimensions. As a result, mixtures, whose compositions previously could not be separated, will become examinable. This in turn could allow us in future to understand more precisely how we should treat our drinking water. Such methods also help identify substances and materials (e.g. food and natural products such as plant extracts) and can be used in some cases for detecting counterfeit products.

As well as pollutants, urban wastewater also contains many recyclables. Often these are, however, only present in very small amounts. Therefore, in collaboration with the affiliated institute DTNW, our scientists are working on the development of absorbent materials, which can be used to enrich valuable materials such as precious metals and rare earths using wastewater. After enrichment, the recyclables can then be recovered in an economical way. This research has been awarded the 2015 Paul Schlack Prize (to Dr. Klaus Opwis), and the KlimaExpo.NRW's 2015 "Engine for Progress" prize.

The Faculty's research in the area of Nanosciences is wide-ranging and highly interdisciplinary. In several projects in the field of Nanomedicine, researchers have succeeded in documenting the benefits of precious metal nanoparticles in medical applications. Gold, for example, is an inert metal that causes no or only minimal reactions in contact with blood or other body fluids. This makes it an optimum carrier material for medical agents. Research groups within our Faculty have developed new methods in recent years for producing microscopic gold nanoparticles and for selectively functionalizing them with essentially any other molecules on the surface. Thus, naked precious metal nanoparticles can also be manufactured in gram quantities using laser ablation, which then react with the molecules present in the solution and bind them to their surface. For this technology, one of the world's fastest ultrafast lasers has been installed in Essen. Its pulses last just two picoseconds, i.e. 0.000,000,000,002 seconds. This is so short that the laser pulses barely heat the material despite the enormously high energy of the laser beam. Thus, laser ablation is very efficient, allowing large amounts of nanoparticles to be produced. It is also so gentle that it can be carried out in the presence of heat-sensitive biomolecules, which are then bonded to the surface of the nascent nanoparticles. These constructs can then be tested for biochemical or medical applications. Often, the efficacy of active ingredients increases on the surface of such nanoparticles, because many of these molecules are simultaneously present and can bind themselves to the biological target. This is referred to as multivalence. In one project, the chemists in Essen have been able to show how the folding and aggregation processes of proteins can be influenced using such surface-functionalized gold nanoparticles. The misfolding of proteins and, in particular, the aggregation of misfolded proteins, is directly linked to neurodegenerative diseases such as Alzheimer's and dementia. Physicochemical, biophysical and biological tests have showed, that the multivalent presentation of small protein molecules on the surface of the nanoparticles inhibits the aggregation of the Aβ-protein – currently the focus of Alzheimer's research. The effect is much stronger than the effect of the protein molecules alone due to the multivalency. This work carried out in the field of nanobiomedicine is therefore contributing to the development of potential drug candidates for protein misfolding diseases. This is a topic that is becoming increasingly important in a world with an ageing population and the associated neurodegenerative diseases such as Alzheimer's.

Besides gold, silver is also a focus of research at our Faculty. It has long been known that silver has an antibacterial effect. For this reason, garments, for example, are coated with silver and refrigerators are fitted on the interior with a thin, invisible layer of silver to prevent the growth of germs and bacteria. However, the silver ions are harmful to healthy human cells. The Essen chemists are therefore investigating, for example, how the antibacterial properties of silver nanoparticles depend on their size and shape (spheres, rods, plates, and cubes). It has been found that the antibacterial effect especially depends on the specific surface area, with their effect on normal human cells being independent of the latter. Particles with a high surface emit the antibacterial silver ions faster, and thus have a higher overall antibacterial effect. This in turn paves the way for the synthesis of bacteria-specific silver nanoparticles that specifically harm bacteria and germs but do little damage to healthy (human) tissue.

In another field, the scientists of the Faculty of Chemistry are exploring how active compounds, proteins and genetic material can be transported into cells. Such transport operations are essential for modern medicine, allowing, for example, specific defective genes in a cell to be repaired by either implanting the missing protein or the healthy gene. Neither proteins nor genetic material, however, can by themselves penetrate the protective sheath of a cell, the membrane. Special transport mechanisms are therefore needed to carry out these tasks. Although viruses (which have been optimized by evolution for millions of years to do just that, namely to introduce their own genetic material into an infected cell) can be used to insert genetic material, such transporter viruses for medical applications are expensive and complicated to produce, and can also cause allergic reactions, which has already resulted in deaths during corresponding clinical trials. One alternative are chemical, non-viral transporters (called vectors). Scientists within our Faculty are working on the development and research of such systems, using a special calcium phosphate nanoparticle or small peptide molecules. In this way, scientists in Essen in cooperation with the Faculty of Biology have succeeded in producing the as yet smallest known peptidic transfection vectors. Crucial here was the replacement of a component naturally found in proteins, the amino acid arginine, with a self-manufactured chemical analogue that binds itself significantly better to both the nucleic acid and the cell surfaces, thereby facilitating the absorption of the genetic material into the cells.

Besides such applied research topics, researchers in the Faculty of Chemistry also carry out very basic research that is paving the way for the research work of tomorrow. In the field of molecular chemistry, for example, they have succeeded in presenting new material precursors for the selective production of the nanoparticular group 15 chalcogenide under mild reaction conditions. The formation of such precursors requires that the stregth and structure of the bonds in complex molecules be extremely precisely controlled. Thus, for the first time, scientists have succeeded in representing antimony analogues of known phosphorus and/or arsenic compounds. Due to the increase in the atomic diameter atomic diameter from phosphorous, to arsenic and antimony, the bonds between the individual atoms became weaker and weaker, so that a considerably gentler synthetic chemistry had to be explored. From such material precursors, ultraprecise nanoparticles and highly-defined thin films can be produced in further steps. The use of molecularly defined and active precursors allows particularly elegant control over the size and shape of particulate systems. Of particular note here is a recently developed method for obtaining such nanoparticles of a particular shape or size via reaction in ionic liquids. Using such thermoelectric materials, it might be possible, among other things, to convert the residual heat of exhaust gases into electrical energy in the future.

Overall, energy research and specifically the synthesis and study of new materials for energy storage and conversion represent another research focus for our Faculty. An important goal here is to bundle together the complementary strengths of the neighbouring sites in the Ruhr region in nanoscience (UDE), chemical analysis (Max Planck Institute for Chemical Energy Conversion and Coal Research, Mülheim a.d.R.) and heterogeneous catalysis (Ruhr University Bochum). Under the leadership of the chemists in Essen, this unique regional pooling of expertise and skills is being used to develop a new catalytic composite, which particularly addresses how the oxidation catalysis in the liquid phase can be purposefully used to investigate fundamental questions of reactivity at interfaces. The scientists of the various bodies and institutions work in close cooperation and carry out research into, among other things, new catalysts for the electrolysis of water that can help to effectively store regenerative electric power generated in the form of chemical fuels.

Another totally different fundamental research question, "From where does life originate?" is also currently being explored at the Faculty of Chemistry. When it comes to the origin of life, there is still no precise understanding of how the first self-replicating molecules and complex systems, e.g. cells, emerged. Without such processes, however, life as we know it would not be possible. The chemists in Essen have been able to develop a model for the formation and self-optimization of vesicles under dynamic environmental conditions. Such models may help with the general understanding of how stable, self-reproducing and self-optimizing systems with molecular and structural evolution are formed. The Essen model exists in the interrelationship of two cyclic processes: a process of periodic vesicle formation and a process in which peptides are in equilibrium with their basic building blocks, the amino acids. The structures that develop from the combination of both processes traverse their own structural and chemical evolution, which can lead to parasitic and symbiotic effects and even the emergence of new functions. The key mechanism is the mutual stabilization of the peptides by the vesicles and the vesicles by the peptides, together with the simultaneously-running selection and reproduction of both components. The temporal evolution of the interlocked cyclic processes represents not only an important aspect of living systems; it also provides a relevant model for the earliest processes that could have led to the emergence of life on Earth. This may represent another small step on the long road to the understanding of life.

Another research focus at the Faculty is the empirical teaching and learning research across the entire spectrum of the education system, from the primary level (general natural sciences), through secondary levels I and II of general and vocational schools, to tertiary education (university). Especially in light of the high drop-out rates from scientific and technical degree courses, the question of what is needed for a successful degree has become increasingly important in recent years. Under the leadership of the Faculty of Chemistry, the DFG Research Group "Studying and academic success in the initial phase of scientific and technical degree courses" (ALSTER) focuses on this topic. The group started working on a total of five projects at the beginning of 2015, and the initial results highlight the importance of the existing knowledge of first-year chemistry students for their academic success. But the research also shows the extent to which this knowledge varies among students depending on the subjects they choose in the sixth grade. For university departments, the resulting key challenge is working out how they should handle the different subject entry requirements. Besides advance knowledge, what is also important for a successful initial study phase is having an iconic model understanding of the subject structure. In the next step, the research group, based on such insights, wants to determine actual training possibilities for improving the initial study phase and thus the overall success of the degree course.