Dream Chemistry Lectures series


    Prof. Konrad Tiefenbacher
Dept. of Chemistry, University of Basel, Switzerland
Dept. of Biosystems Science and Engineering, ETH Zurich, Switzerland

"Terpene Biosynthesis as Inspiration for Supramolecular Catalysis"

25 April 2019, 10:00
Abstract:
Nature’s extraordinary elegance when performing chemical reactions has fascinated and inspired chemists for decades. Arguably, one of the most complex organic transformations performed in living organisms, is the tail-to-head terpene (THT) cyclization. It allows the construction of the most diverse class of natural products, namely terpenes, via nature’s way of combinatorial chemical synthesis. Thousands of different natural products are formed from just a handful of simple, acyclic starting materials: geranyl pyrophosphate (monoterpenes), farnesyl-PP (sesquiterpenes) and geranylgeranyl-PP (diterpenes). Nature utilizes enzymes, termed cyclases or terpene synthases, to carry out this complex transformation. Building upon our initial results, we explore possibilities to utilize supramolecular structures to mimic such complex transformations in the laboratory.

 

    Dr. M. Selim Hanay
Dept. of Mechanical Engineering, Bilkent University, Ankara, Turkey
National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey

"Resonator-Based Spectroscopy: Sizing Cells and Large Molecules"

21 March 2019, 10:00
Abstract:
Mechanical and Electromagnetic Resonators at the micro/nanoscale can be used as exquisite sensors of physical changes, such as the mass and polarizability of a species. We will explore two such sensing paradigms in this talk:
1) Nanoelectromechanical Systems (NEMS) for the Mass Spectrometry of large single biomolecules and nanoparticles, and
2) Microfluidics-Integrated Microwave Sensors for sizing of single cells.

In the first half of the talk (NEMS based Mass Spectrometry), I will argue that conventional forms of Mass Spectrometry face certain challenges when the molecular weight of the species becomes larger than the MegaDalton range which is the regime for large biomolecules, organelles and viruses. In this mass range, nanomechanical devices can offer novel advantages in terms of mass spectrometry, and beyond —such as the simultaneous extraction of molecular shape information. The principles developed for the mechanical resonators can be extended to electromagnetic resonators. For instance, the microwave frequency range seems extremely advantageous for accurate sizing of single-cells in a microfluidic environment. Thus, in the second half of my talk, I will focus on this new approach, a radar for cells, for performing real-time single cell analysis.

 

    Dr. Jesús Campos
Institute for Chemical Research (IIQ), CSIC-University of Sevilla, Spain

"Developing new cooperative strategies for catalysis, or dreaming about it"

7 March 2019, 10:00
Abstract:
In the early 80s Chisholm proposed that “all the types of reactions which have been studied for mononuclear transition metal complexes will also occur for dinuclear transition metal complexes”. Almost 40 years later, continued research on the area of bimetallic systems has proven that claimed and gone beyond, even exploiting the chemistry of many polymetallic and cluster species. Regarding catalytic applications, there are many important transformations that require the concerted action of pairs of active metal sites, paralleling what is often found in metalloenzymes. This fertile area of research inspired us to start investigating less explored concepts in the field of cooperative chemistry with the aim of developing novel catalytic applications. In one of our approaches, we focused on late-transition bimetallic systems characterized by the use of sterically hindered phosphine ligands containing a terphenyl (2,6-C 6 H 3 -Ar 2 ) substituent. We now can tune the formation of M-M bonds versus M···M frustration with interesting outcomes in terms of reactivity. In a related approach and within a dreaming standpoint we have also tried to develop cooperative molecular materials that rely on Coulombic forces to produce heterogeneized catalysts. The two strategies, namely our future dreaming chemistry and also our down-to-Earth results on bimetallic pairs will be discussed.

 

    Dr. Thomas Juffmann
Max F.Perutz Laboratories, University of Vienna, Austria

"Can we image the folding conformation of a single protein?"

21 February 2019, 10:00
Abstract:
Optical phase contrast microscopy and cryo-electron microscopy are widely used in the study of cells and proteins, respectively. In both techniques, a specimen imparts a phase shift on the probe (photons or electrons), which can be measured using various interferometric techniques.
In this talk I will briefly discuss the physical basics and limits of phase microscopy, and will show ways how to improve on current techniques using wave-front shaping, cavity or quantum enhanced measurements. I will demonstrate how wave-front shaping can enable phase contrast imaging with optimized sensitivity all across the field of view, and how multi-passing the probe particles through a sample can be used for high sensitivity / low damage imaging. The latter could potentially allow for cryo-electron microscopy with unprecedented resolution.

 

    Prof. Dr. Pablo Rivera-Fuentes
Dept of Chemistry and Applied Bioscences, ETH Zürich, Switzerland

"Chemical tools for single-molecule imaging in live cells"

7 February 2019
Abstract:
Single-molecule imaging enables the observation of cellular structures with nanometric resolution. In densely labeled samples, however, emission from molecules that are closer than the diffraction limit of light appear as a single signal. To enable the localization of such molecules beyond the diffraction limit, photoactivatable or photoswitchable dyes have been developed. In recent work, we extended this concept to combine photoactivation and other chemical processes to tackle some of the current challenges in single-molecule imaging. For example, we have developed probes that enable the observation of single molecules of enzymes based on their activity. We have also created fluorophores with a polarity-dependent photoactivation mechanism, allowing to image intracellular lipid domains with nanometric resolution. Moreover, dyes that combine photoactivation and fluxional equilibria have allowed us to perform very long time-lapse, super-resolved imaging of synaptic vesicles in live human neurons with minimal phototoxicity or photobleaching. These experiments have revealed details of the 3D compartmentalization of these vesicles.

 

    Dr. David Martinez-Martin
Dept of Biosystems Science and Engineering, ETH Zürich, Switzerland

"Tracking a cell's mass in real time: a new indicator of cell physiology"

24 January 2019
Biography

  • Bachelor’s + Master’s degree in Physics (2005). University of Valladolid (Spain). Summa Cum Laude
  • PhD in Physics (2011). Autonomous University of Madrid (Spain). Summa Cum Laude
  • Postdoctoral EMBO Fellowship. ETH Zurich (2013-2015)
  • Scientist and Project Manager. ETH Zurich (2016-currently)
  • Senior Lecturer. University of Sydney (offer accepted)
  • Selected achievement: Technology to measure mass changes of a single living cell in real time.
 

    Dr. Dominik Kubicki
Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland

"How Physical Chemistry advances Materials Science: solid-state NMR of lead halide perovskites for optoelectronics"

19 December 2018
Abstract:
Organic-inorganic lead halide perovskites are a promising family of light absorbers for a new generation of LEDs and solar cells, with reported efficiencies currently exceeding 22%. The field of perovskite photovoltaics is largely driven by systematic optimization of numerous parameters affecting the performance of perovskite solar cells. Such a trial-and-error approach, not backed up by atomic-level understanding of the reasons behind successes and failures, makes rational design of new compositions with better properties extremely difficult. Here, I will show how we use high-field multi-nuclear (1H, 2H, 13C, 14N, 15N, 133Cs, 87Rb, 39K) solid-state magic angle spinning NMR to provide for the first time atomic-level understanding of the different doping strategies used to improve photovoltaic performance of lead halide perovskites. These advances were largely enabled by a new solid-state method of synthesizing highly pure and crystalline lead halide perovskites: mechanosynthesis.