Lecture from 15.09.2021

Prof. Dr. Rainer Haag, Universität Hamburg und Institute of Chemistry and Biochemistry, Freie Universität Berlin

Functional Biointerfaces based on Multivalent Polyglycerol Architectures

Functional biointerfaces are part of the new collaborative research center SFB 1449 and the research building SupraFAB that forms a bridge between Biology, Chemistry and Physics. It also presents a perfect link to the Federal Institute of Material Research and Testing (BAM). In my presentation, I will focus on two functional biointerfaces: (i) universal surface coatings for biospecific cell binding and multivalent hybrid nanoparticles to block virus infections.

A new “adsorption-cross-linking” technology is presented to generate a highly dense polymer coating on various nonpolar substrates, including the most inert and low-energy surfaces of PDMS and PTFE. This prospective surface modification strategy is based on a tailored bifunctional amphiphilic block copolymer with benzophenone units as the hydrophobic anchor/chemical cross-linker and terminal azide groups for in situ postmodification. The resulting polymer brushes exhibited long-term and ultralow protein adsorption and cell adhesion benefiting from the high density and high hydration ability of polyglycerol blocks. The presented antifouling brushes provided a highly stable and robust bioinert background for biospecific adsorption of desired proteins and cells after secondary modification with bioactive ligands.

Blocking virus binding with host cells with binding decoys can inhibit virus infection at the entry step. Overcoming the heterogenicity of difference virus strains and developing broad-spectrum inhibitors has become an important task for the chemists and virologists. The virions of SARS-CoV-2 and Influenza A are nanoparticles around 100 nm, which can be targeted by different multivalent nanostructures. Herein, I present novel hybrid nanoparticles of different shapes that can efficiently block the binding of viruses to host cell surfaces.

Selected References

  1. Nie, C.; Stadtmüller, M.; Parshad, B.; Wallert, M.; Kerkhoff, Y.; Bhatia, S.; Block, S.; Cheng, C.; Wolff, T.; Haag, R.; Heteromultivalent topology-matched nanostructures as potent and broad-spectrum influenza A virus inhibitors. Sci. Adv., 2021, 7, eabd3803.
  2. Cheng, C.; Zhang, J.; Li, S.; Xia, Y.; Nie, C.; Shi, Z.; Cuellar-Camacho, J. L.; Ma, N.; Haag, R.; A water-processable and bioactive multivalent graphene nano-ink for highly flexible bio-electronic films and nanofibers. Adv. Mater., 2018, 30, 1705452.
  3. Qi, Z.; Bharate, P.; Lai, C. H.; Ziem, B.; Böttcher, C.; Schulz, A.; Beckert, F.; Hatting, B.; Mülhaupt, R.; Seeberger, P. H.; Haag, R., Multivalency at Interfaces: Supramolecular Carbohydrate-Functionalized Graphene Derivatives for Bacterial Capture, Release, and Disinfection. Nano Lett. 2015, 15, 6051-6057.
  4. Wei, Q.; Becherer, T.; Noeske, P.-L. M.; Grunwald, I.; Haag, R., A universal approach to crosslinked hierarchical polymer multilayers as stable and highly efficient antifouling coatings. Adv. Mater. 2014, 26, 2688–2693.

Contact: Dr. Ute Resch-Genger, ute.resch[at]bam.de

Lecture from 27.08.2021

Prof. Dr. Claudia Felser, Director and Scientific Member at the Max Planck Institute for Chemical Physics of Solids, Dresden

Topology and Chirality

Topology, a mathematical concept, recently became a hot and truly transdisciplinary topic in condensed matter physics, solid state chemistry and materials science. All 200 000 inorganic materials were recently classified into trivial and topological materials: topological insulators, Dirac, Weyl and nodal-line semimetals, and topological metals [1]. The direct connection between real space: atoms, valence electrons, bonds and orbitals, and reciprocal space: bands and Fermi surfaces allows for a simple classification of topological materials in a single particle picture. More than 25% of all inorganic compounds host topological bands, which opens also an infinitive play-ground for chemistry [1,2]. Beyond Weyl and Dirac, new fermions can be identified in compounds that have linear and quadratic 3-, 6- and 8- band crossings that are stabilized by space group symmetries [3]. Crystals of chiral topological materials CoSi, AlPt and RhSi were investigated by angle resolved photoemission and show giant unusual helicoid Fermi arcs with topological charges (Chern numbers) of ±2 [4]. In agreement with the chiral crystal structure two different chiral surface states are observed. A quantized circular photogalvanic effect is theoretically possible in Weyl semimetals. However, in the multifold fermions with opposite chiralities where Weyl points can stay at different energies, a net topological charge can be generated. [5]. However, chirality is also of interest for chemists [6], especially because of the excellent catalytic performance of the new chiral Fermions AlPt and PdGa [7]. The open question is the interplay between Berry curvature, chirality, orbital moment and surface states.

1. Bradlyn et al., Nature 547 298, (2017), Vergniory, et al., Nature 566 480 (2019), Xu et al. Nature 586 (2020) 702.
2. Nitesh Kumar, Satya N. Guin, Kaustuv Manna, Chandra Shekhar, and Claudia Felser, doi.org/10.1021/acs.chemrev.0c00732
3. Bradlyn, et al., Science 353, aaf5037A (2016)
4. Sanchez et al., Nature 567 (2019) 500, Schröter et al., Nature Physics 15 (2019) 759, Schröter Science 369 (2020) 179, Sessi et al, Nature Communications 11 (2020) 3507, Yao et al., Nature Communications 11 (2020) 2033
5. Dylan Rees, et al., Science Advances 6 (2020) eaba0509, Congcong Le, Yang Zhang, Claudia Felser, Yan Sun, Physical Review B 102 (2020) 121111(R), Zhuoliang Ni, et al., npj Quantum Materials volume 5 (2020) 96, Zhuoliang Ni, et al.,, Nature Communications 12 (2021) 154
6. B. Yan, et al., Nature Com. 6 (2015) 10167, Guowei Li and Claudia Felser, APL 116 (2020) 070501.
7. Qun Yang, et al., Advanced Materials 32 (2020) 1908518, Guowei Li, to be published

Contact at BAM: Dr. Franziska Emmerling, franziska.emmerling[at]bam.de

Lecture from 23.07.2021

Prof. Dr. Hubert A. Gasteiger, Chair of Technical Electrochemistry, Chemistry Department, Technical University of Munich

Battery or Fuel Cell Electric Vehicles - Technological, Economical, and Ecological Constraints for Sustainable Electromobility?

Driven by global warming, the global community is seeking to expand and integrate renewable energy sources and to decarbonize the transportation sector, which has a significant share in the world-wide CO2 emissions. To address the latter, the development and deployment of battery electric vehicles (BEVs) has been accelerated over the past 10 years. Nevertheless, significant short-comings of BEVs still have to be overcome to further increase their market penetration, particularly, driving range and rechargeability.

On the other hand, hydrogen can be used as energy carrier for temporary large-scale energy storage and for powering fuel cell electric vehicles (FCEVs). Proton exchange membrane (PEM) based water electrolyzers and fuel cells are nowadays the most promising candidates for the generation of high-pressure hydrogen and for powering FCEVs. However, both technologies currently require significant amounts of costly and supply-limited precious metals, which could restrict the large-scale implementation of PEM electrolyzers and fuel cells, so that improved catalyst and electrode concepts must be devised.

This presentation will discuss and compare the remaining challenges for BEVs and for H2 generation and use that still need to be tackled on the path towards sustainable electromobility.

Contact at BAM: Dr. Thomas Goedecke, thomas.goedecke[at]bam.de

Lecture from 14.07.2021

Prof. Dr. Horst Weller, Universität Hamburg - Institut für Physikalische Chemie & Fraunhofer Zentrum für Angewandte Nanotechnologie

Synthesis, Properties and Applications of Nanocrystals in Materials and Life Sciences

Although colloidal nanocrystals of many different materials can be synthesized in high quality in respect of size, shape and crystallinity, our understanding of their formation and the involved chemical reactions is still rather poor. We will present analytical studies on nucleation and growth as well as ion exchange processes in nanocrystals. These include mass spectrometric, optical, electron microscopic and x-ray synchrotron experiments.

Almost all applications of nanocrystals require the control of surface properties in respect of solubility, miscibility, biocompatibility, passivation of surface states as well as electronic and magnetic interaction with the environment. We will show various examples for ligand exchange and encapsulation of quantum dots, plasmonic and magnetic nanocrystals and will report on applications as high-performance ceramics, for display and lighting, electrocatalysis as well as for biolabeling and drug delivery.

Contact at BAM: Dr. Ute Resch-Genger, ute.resch[at]bam.de

Lecture from 10.06.2021

Dr. Mark S. Kozdras, Program Manager & Clean Energy Materials Innovation Challenge Co-lead CanmetMATERIALS, Energy Technology Sector, Natural Resources Canada

MAPs: a Modern Alchemy

Self-driving laboratories are natural extensions of factorial experiments, combinatorial methods and high throughput experimentation. With technology advancing at exponential rates, high performance computing, robotic automation and artificial intelligence (AI) have emerged as powerful enablers of benchtop experimentation. However, urgent societal challenges are driving us to innovate faster. Materials Acceleration Platforms, a novel approach to accelerate the discovery and development of advanced materials, has accepted the challenge

Contact at BAM: Dr. Özlem Özcan Sandikcioglu, ozlem.ozcan[at]bam.de

Lecture from 04.06.2021

Prof. Dr. Detlef Günther, Departement für Chemie und Biowissenschaften ETH Zürich, Schweiz

Die Freuden und Leiden der Analytischen Chemie

Die 150-jährige Geschichte der Bundesanstalt für Materialprüfung (BAM) ist untrennbar mit der Geschichte der analytischen Chemie verwoben. 1871 wurde das Periodensystem der Elemente aufgestellt - im gleichen Jahr wurde die Vorgängerorganisation der BAM gegründet. Nachdem Bunsen und Kirchhoff die Spektralanalyse eingeführt hatten, begann die Blütezeit der instrumentellen Elementanalytik mit der Entwicklung der Hohlkathodenlampe durch Walsh, die mit der Atomabsorptionsspektrometrie (AAS) breite Anwendung fand. Greenfield und Fassel ermöglichten mit der Induktiv gekoppelten Plasmaspektrometrie (ICP-OES) den Zugang zur Multielementanalytik und erweiterten das Spektrum der Applikationen wesentlich. Houk gelang 1980 die erste Kopplung eines ICP mit einem Massenspektrometer (ICP-MS). Von da an wurde die Entwicklung dieser Methode zu einem der wichtigsten Forschungsgebiete der Elementanalytik, auch in Bezug auf die Kopplung mit der Laser Ablation, die von Gray 1985 erfolgreich realisiert wurde (LA-ICP-MS).

Die letzten 40 Jahre waren stark von der Weiterentwicklung der ICP-Massenspektrometrie und diverser Kopplungstechniken gekennzeichnet. Ausgewählte Beispiele, wie die Bedeutung der TOF-MS (erstmals von Hieftje 1994 realisiert) für die quasi-simultane Detektion der Isotope, werden im Vortrag näher diskutiert, um die sich fortlaufend erweiternden Möglichkeiten der Elementspurenanalytik aufzuzeigen.

Trotz der Erfolgsgeschichte von neuen Instrumenten und kontinuierlich verfeinerten Methoden hat die Analytik ihre Position im universitären Umfeld nicht wirklich etablieren können. Die Frage nach «Central Science or Central Service?» wird immer häufiger gestellt; und das, obwohl Umweltmonitoring, Materialcharakterisierung, Toxikologie, Kriminalistik, Geologie bis hin zur Medizin alles Gebiete sind, in denen die Methoden der Elementanalytik zwingend gebraucht werden. Diese Kontroverse soll näher beleuchtet werden. Die Zukunft muss Fragen nach höherer Empfindlichkeit, Matrixunabhängigkeit, Genauigkeit und Richtigkeit der Analysenergebnisse wieder vermehrt aufnehmen, wie es die BAM mit der Weiterentwicklung der Methoden und von neuen Referenzmaterialien tut. Wenn die Erkenntnisse der Elementanalytik in die Debatten über Klima, Umweltschutz, Nachhaltigkeit, Ernährung, Gesundheit und Mobilität richtig eingebracht und somit die Wissenschaft mit Wirkung verbunden werden kann, dann sollten weitere 150 erfolgreiche Jahre vor der BAM liegen. Alle diese Themen werden neue Materialien benötigen und diese müssen «state-of-the-art» charakterisiert werden, um auch weiterhin «Sicherheit in Technik und Chemie» zu gewährleisten.

Kontakt BAM: Dr. Björn Meermann, bjoern.meermann[at]bam.de

Lecture from 12.05.2021

Prof. Katharina Landfester, Max Planck Institute for Polymer Research (MPI) Mainz, Germany

Nanocapsules: Challenges for Biomedical Applications

Our vision is to construct multipotent drug-loaded nanocapsules of high homogeneity in size and surface functionality, which find their target cells in the desired organs and release the drug in a controlled manner in the cytoplasm of these cells. For the delivery of bioactive compounds to a specific cell, it is not only vital to improve the stability of the therapeutic agent during passage through the blood stream, but also to extend the circulation time in the body.

Making smart nanoparticles is inevitably linked to a deep understanding of the overall physico-chemical principle of their formation. By means of the miniemulsion process, we design custom-made nanoparticles and nanocapsules for biomedical applications. This is facilitated by the enormous versatility of the miniemulsion process that has been developed and conceptually understood by our group. Moreover, the accumulation of understanding the formation process has led to successful and precise control of important nanoparticle parameters such as size, shape, morphology, surface functionalization and modification, degradation, release kinetics. This degree of control is unique and allows us to tune specific properties tailored to particular applications; the successful up-scaling of process is of technical relevance. Furthermore, the encapsulation and release of a great variety of payloads, ranging from hydrophobic to hydrophilic substances has been successfully achieved in a highly controlled manner and with an unmatched high encapsulation efficiency.

For biomedical application, many interactions to biological matter have to be considered and tuned: the interaction with blood components (proteins etc.) has to be controlled to limit aggregation processes. Furthermore, the interaction to cell membranes and uptake in blood cells like macrophages has to be minimized. Only then the drug can reach the target cells. The specific interaction to target cells have to be tuned.

Contact at BAM: Dr. Ute Resch-Genger, ute.resch[at]bam.de

Lecture from 13.04.2021

Prof. Dr.-Ing. habil. Michael Hübner, Brandenburg University of Technology Cottbus-Senftenberg (BTU Cottbus Senftenberg)

Next Generation Cyberphysical Systems with local AI based Intelligence

The increasing demands in regards to complexity, flexibility and self-organization of networked embedded systems require new solutions for the local processor architectures and firmware. This includes the ability to react to the inner system status as well to acquired data e.g. from a sensor value measured in a process.

Artificial intelligence becomes ubiquitous and therefore enters also the domain of embedded systems which therefore enables to exploit the powerful opportunities of this methods even locally at the embedded sensor systems. The so called edge computing will introduce new degrees of freedom in embedded and Cyberpyhsical systems and is very promising to support the aforementioned demands tremendously.

In this talk, possible solutions for next generation embedded systems with AI components will be introduced. Methods to exploit offline and online techniques from the AI domain will be presented. Finally, selected real world applications from the process and production industry including results will be introduced.

Contact at BAM: Dr. habil. Michael Maiwald, michael.maiwald[at]bam.de

Lecture from 30.03.2021

Dr. Kristina Tschulik, Ruhr-Universität Bochum (RUB)

Advances Electrochemical Approaches for Nanomaterial Characterization and Renewable Energy Technologies

Over the past two decades, electrochemistry has undergone a remarkable renaissance in the perception of many scientists. From a supposedly exhaustively srtudied discipline, it transformed into modern and versatile toolbox for basic physicochemical studies, smart bio- and nanoparticle sensors, environmentally friendly synthesis approaches, and renewable energy technologies.

This transformation has been driven primarily by the goal of sustainable conversion and storage of energy from renewable energy sources and non-fossil fuels, as almost all technologies discussed for this purpose are based on electrochemical processes: Batteries, supercapacitors, photovoltaic cells, water electrolyzers, fuel cells, etc. Since electrochemical reactions always occur at an electrode, the transport of reactants and products to and from the electrode play a significant role in addition to reaction kinetics, which complicates quantitative understanding. Nanomaterials are often used to achieve large surface areas and high reaction rates. Their reactivity and degradation are insufficiently described by traditional electrochemical concepts. This inhibits the characterization - and thus the targeted further development - of nanocatalysts, as well as active materials and requires the development of novel electrochemical methods. Such new electrochemical methods for the determination of intrinsic nanomaterial properties and reactivities will be discussed in the talk. Besides fundamental research aspects, also perspectives to utilize electrochemical methods in sensing will be highlighted.

Contact at BAM: Dr.-Ing. Anja Waske, Anja.Waske[at]bam.de

Lecture from 23.03.2021

Zoltan Mester, National Research Council Canada

CRMs for the next fifty years

Certified reference materials are an important tool for quality assurance in analytical chemistry and many other fields. In the lecture, future developments and trends in the field of reference materials will be highlighted. In connection with this, important aspects from metrology and standardization (ISO TC 334, ISO REMCO) will be discussed.

Contact at BAM: Dr. Sebastian Recknagel, Sebastian.Recknagel[at]bam.de

Symposium from 04.03.2021

The digital symposium on "Trust in Future Technologies" kicked off in March.