ERC FUNDED PROJECTS

The emergence of coherent behaviour is ubiquitous in the natural world and has long captivated biologists and physicists alike. One area of growing interest is the collective motion and synchronization arising within and between simple motile organisms. My goal is to develop and use a novel experimental approach to unravel the origins of spontaneous coherent motion in three model systems of biofluids: (1) the synchronization of the two flagella of green algae Chlamydomonas Rheinhardtii, (2) the metachronal wave in the cilia of protist Paramecium and (3) the collective motion of swimming microorganisms in active suspensions. Understanding the mechanisms leading to collective motion is of tremendous importance because it is crucial to many biological processes such as mechanical signal transduction, embryonic development and biofilm formation. Up till now, most of the work has been theoretical and has led to the dominant view that hydrodynamic interactions are the main driving force for synchronization and collective motion. Recent experiments have challenged this view and highlighted the importance of direct mechanical contact. New experimental studies are now crucially needed. The state-of-the-art of experimental approaches consists of observations of unperturbed cells. The key innovation in our approach is to dynamically interact with microorganisms in real-time, at the relevant time and length scales. I will investigate the origins of coherent motion by reproducing synthetically the mechanical signatures of physiological flows and direct mechanical interactions and track precisely the response of the organism to the perturbations. Our new approach will incorporate optical tweezers to interact with motile cells, and a unique μ-Tomographic PIV setup to track their 3D micron-scale motion. This proposal tackles a timely question in biophysics and will yield new insight into the fundamental principles underlying collective motion in active biological matter.

1 500 000 €

Start date: 2017-04-01, End date: 2022-03-31

This proposal aims to develop a generic synthesis approach for core-shell nanoparticles by unravelling the relevant mechanisms. Core-shell nanoparticles have high potential in heterogeneous catalysis, energy storage, and medical applications. However, on a fundamental level there is currently a poor understanding of how to produce such nanostructured particles in a controllable and scalable manner. The main barriers to achieving this goal are understanding how nanoparticles agglomerate to loose dynamic clusters and controlling the agglomeration process in gas flows during coating, such that uniform coatings can be made. This is very challenging because of the two-way coupling between agglomeration and coating. During the coating we change the particle surfaces and thus the way the particles stick together. Correspondingly, the stickiness of particles determines how easy reactants can reach the surface. Innovatively the project will be the first systematic study into this multi-scale phenomenon with investigations at all relevant length scales. Current synthesis approaches – mostly carried out in the liquid phase – are typically developed case by case. I will coat nanoparticles in the gas phase with atomic layer deposition (ALD): a technique from the semi-conductor industry that can deposit a wide range of materials. ALD applied to flat substrates offers excellent control over layer thickness. I will investigate the modification of single particle surfaces, particle-particle interaction, the structure of agglomerates, and the flow behaviour of large number of agglomerates. To this end, I will apply a multidisciplinary approach, combining disciplines as physical chemistry, fluid dynamics, and reaction engineering.

1 409 952 €

Start date: 2011-12-01, End date: 2016-11-30

Toroidal processive enzymes (e.g. enzymes/proteins that are able to thread onto biopolymers and to perform stepwise reactions along the polymer chain) are among the most fascinating tools involved in the clockwork machinery of life. Processive catalysis is ubiquitous in Nature, viz. DNA polymerases, endo- and exo-nucleases and; it plays a crucial role in numerous events of the cell’s life, including most of the replication, transmission, and expression and repair processes of the genetic information. In the case of DNA polymerases the protein catalyst encircles the DNA and whilst moving along it, make copies of high fidelity. Although numerous works have been reported in relation with the synthesis of natural enzymes' analogues, very few efforts have been paid in comparison to mimic these processive properties. It is the goal of this proposal to rectify this oversight and unravel the essential components of Nature’s polymer catalysts. The individual projects are designed to specifically target the essential aspects of processive catalysis, i.e. rate of motion, rate of catalysis, and transfer of information. One project is aimed at extending the research into a processive catalytic system that is more suitable for industrial application. Two projects involve more farsighted studies and are designed to push the research way beyond the current boundaries into the area of Turing machines and bio-rotaxane catalysts which can modify DNA in a non-natural process. The vision of this proposal is to open up the field of ‘processive catalysis’ and invigorate the next generation of chemists to develop information transfer and toroidal processive catalysts. The construction of synthetic analogues of processive enzymes could open a gate toward a large range of applications, ranging from intelligent tailoring of polymers to information storage and processing.

1 603 699 €

Start date: 2012-02-01, End date: 2017-01-31

Massive stars play many key roles in Astrophysics. As COSMIC ENGINES they transformed the pristine Universe left after the Big Bang into our modern Universe. We use massive stars, their explosions and products as COSMIC PROBES to study the conditions in the distant Universe and the extreme physics inaccessible at earth. Models of massive stars are thus widely applied. A central common assumption is that massive stars are non-rotating single objects, in stark contrast with new data. Recent studies show that majority (70% according to our data) will experience severe interaction with a companion (Sana, de Mink et al. Science 2012). I propose to conduct the most ambitious and extensive exploration to date of the effects of binarity and rotation on the lives and fates of massive stars to (I) transform our understanding of the complex physical processes and how they operate in the vast parameter space and (II) explore the cosmological implications after calibrating and verifying the models. To achieve this ambitious objective I will use an innovative computational approach that combines the strength of two highly complementary codes and seek direct confrontation with observations to overcome the computational challenges that inhibited previous work. This timely project will provide the urgent theory framework needed for interpretation and guiding of observing programs with the new facilities (JWST, LSST, aLIGO/VIRGO). Public release of the model grids and code will ensure wide impact of this project. I am in the unique position to successfully lead this project because of my (i) extensive experience modeling the complex physical processes, (ii) leading role in introducing large statistical simulations in the massive star community and (iii) direct involvement in surveys that will be used in this project.

1 926 634 €

Start date: 2017-09-01, End date: 2022-08-31