ERC FUNDED PROJECTS

I propose to investigate the nanometer scale organization of delicate 2-dimensional molecular materials using nanoscale vibrational spectroscopy. 2D structures are of great scientific and technological importance, for example as novel materials (graphene, MoS2, WS2, etc.), and in the form of biological membranes and synthetic 2D-polymers. Powerful methods for their analysis and imaging with molecular selectivity and sufficient spatial resolution, however, are lacking. Tip-enhanced Raman spectroscopy (TERS) allows label-free spectroscopic identification of molecular species, with ≈10 nm spatial resolution, and with single molecule sensitivity for strong Raman scatterers. So far, however, TERS is not being carried out in liquids, which is the natural environment for membranes, and its application to poor Raman scatterers such as components of 2D polymers, lipids, or other membrane compounds (proteins, sugars) is difficult. TERS has the potential to overcome the restrictions of other optical/spectroscopic methods to study 2D materials, namely (i) insufficient spatial resolution of diffraction-limited optical methods; (ii) the need for labelling for all methods relying on fluorescence; and (iii) the inability of some methods to work in liquids. I propose to address a number of scientific questions associated with the spatial organization, and the occurrence of defects in sensitive 2D molecular materials. The success of these studies will also rely critically on technical innovations of TERS that notably address the problem of energy dissipation. This will for the first time allow its application to study of complex, delicate 2D molecular systems without photochemical damage.

2 311 696 €

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

"Understanding structure-property relationships across lengthscales is key to the design of functional and structural materials and devices. Moreover, the complexity of modern devices extends to three dimensions and as such 3D characterization is required across those lengthscales to provide a complete understanding and enable improvement in the material’s physical and chemical behaviour. 3D imaging and analysis from the atomic scale through to granular microstructure is proposed through the development of electron tomography using (S)TEM, and ‘dual beam’ SEM-FIB, techniques offering complementary approaches to 3D imaging across lengthscales stretching over 5 orders of magnitude. We propose to extend tomography to include novel methods to determine atom positions in 3D with approaches incorporating new reconstruction algorithms, image processing and complementary nano-diffraction techniques. At the nanoscale, true 3D nano-metrology of morphology and composition is a key objective of the project, minimizing reconstruction and visualization artefacts. Mapping strain and optical properties in 3D are ambitious and exciting challenges that will yield new information at the nanoscale. Using the SEM-FIB, 3D ‘mesoscale’ structures will be revealed: morphology, crystallography and composition can be mapped simultaneously, with ~5nm resolution and over volumes too large to tackle by (S)TEM and too small for most x-ray techniques. In parallel, we will apply 3D imaging to a wide variety of key materials including heterogeneous catalysts, aerospace alloys, biomaterials, photovoltaic materials, and novel semiconductors. We will collaborate with many departments in Cambridge and institutes worldwide. The personnel on the proposal will cover all aspects of the tomography proposed using high-end TEMs, including an aberration-corrected Titan, and a Helios dual beam. Importantly, a postdoc is dedicated to developing new algorithms for reconstruction, image and spectral processing."

2 337 330 €

Start date: 2012-01-01, End date: 2017-12-31

State-of-the-art microscopy and diffraction imaging provides insight into the atomic and sub-atomic structure of matter. They permit determination of the positions of atoms in a crystal lattice or in a molecule as well as the distribution of electrons inside atoms. State-of-the-art time-resolved spectroscopy with femtosecond and attosecond resolution provides access to dynamic changes in the atomic and electronic structure of matter. Our proposal aims at combining these two frontier techniques of XXI century science to make a long-standing dream of scientist come true: the direct observation of atoms and electrons in their natural state: in motion. Shifts in the atoms positions by tens to hundreds of picometers can make chemical bonds break apart or newly form, changing the structure and/or chemical composition of matter. Electronic motion on similar scales may result in the emission of light, or the initiation of processes that lead to a change in physical or chemical properties, or biological function. These motions happen within femtoseconds and attoseconds, respectively. To make them observable, we need a 4-dimensional (4D) imaging technique capable of recording freeze-frame snapshots of microscopic systems with picometer spatial resolution and femtosecond to attosecond exposure time. The motion can then be visualized by slow-motion replay of the freeze-frame shots. The goal of this project is to develop a 4D imaging technique that will ultimately offer picometer resolution is space and attosecond resolution in time.

2 500 000 €

Start date: 2010-03-01, End date: 2015-02-28

Optical bioimaging is limited by visible light penetration depth and stability of fluorescent dyes over extended periods of time. Surface enhanced Raman scattering (SERS) offers the possibility to overcome these drawbacks, through SERS-encoded nanoparticle tags, which can be excited with near-IR light (within the biological transparency window), providing high intensity, stable, multiplexed signals. SERS can also be used to monitor relevant bioanalytes within cells and tissues, during the development of diseases, such as tumours. In 4DBIOSERS we shall combine both capabilities of SERS, to go well beyond the current state of the art, by building three-dimensional scaffolds that support tissue (tumour) growth within a controlled environment, so that not only the fate of each (SERS-labelled) cell within the tumour can be monitored in real time (thus adding a fourth dimension to SERS bioimaging), but also recording the release of tumour metabolites and other indicators of cellular activity. Although 4DBIOSERS can be applied to a variety of diseases, we shall focus on cancer, melanoma and breast cancer in particular, as these are readily accessible by optical methods. We aim at acquiring a better understanding of tumour growth and dynamics, while avoiding animal experimentation. 3D printing will be used to generate hybrid scaffolds where tumour and healthy cells will be co-incubated to simulate a more realistic environment, thus going well beyond the potential of 2D cell cultures. Each cell type will be encoded with ultra-bright SERS tags, so that real-time monitoring can be achieved by confocal SERS microscopy. Tumour development will be correlated with simultaneous detection of various cancer biomarkers, during standard conditions and upon addition of selected drugs. The scope of 4DBIOSERS is multidisciplinary, as it involves the design of high-end nanocomposites, development of 3D cell culture models and optimization of emerging SERS tomography methods.

2 410 771 €

Start date: 2018-10-01, End date: 2023-09-30