KTH Royal Institute of Technology
My research interest is focused on the establishment and development of advanced light microscopy techniques and its application to the life sciences.
Fluorescence microscopes, and especially their confocal and two-photon variants, are unique in their ability to directly observe morphological changes and molecular reactions in living cells. However, due to diffraction of light, the lateral resolution of conventional light microscopes is limited to about 200-300 nm. This limitation is overcome with great success by the field of super-resolution microscopy. Here, fluorescence molecules do not only act as probes to highlight features of interest, but their photophysical properties are used for overcoming the diffraction limit of light. By controlling those properties in space or time with light it is possible to improve the spatial resolution of an optical microscope down to the molecular scale (10-20nm).
My overarching scientific objective is to develop novel paradigms and concepts based on super-resolution microscopy to address contemporary challenges in biophysics and molecular biology. To achieve these goals I will push forward the quantitative aspect of live cell imaging by setting-up and applying different concepts of super-resolution microscopy based on single molecule detection (PALM/STORM/GSDIM) and targeted switching (STED/RESOLFT). These next generation microscopes will allow the precise identification of populations of biomolecules depending on their localization, abundance and dynamics inside their native environment. A special effort will be dedicated to investigate neuronal proteins, especially in synapses, where trafficking organelles and protein complexes are packed so tight in space that resolving them requires high resolution in space and time.
Ilaria Testa, Elisa D’Este, Nicolai T. Urban, Francisco Balzarotti, Stefan W. Hell (2014) Dual Channel RESOLFT Nanoscopy by Using Fluorescent State Kinetics, Nano Letters, 15:103-6 doi: 10.1021/nl503058k
Ilaria Testa, Nicolai T. Urban, Stefan Jakobs, Christian Eggeling, Katrin I. Willig, Stefan W. Hell (2012) Nanoscopy of living brain slice with low light levels, Neuron 75: 992–1000 doi: 10.1016/j.neuron.2012.07.028
Tim Grotjohann*, Ilaria Testa*, Matthias Reuss, Tanja Brakemann, Christian Eggeling, Stefan W Hell, Stefan Jakobs (2012) rsEGFP2 enables fast RESOLFT nanoscopy of living cells, eLIFE Sciences 1:1-14 doi: 10.7554/eLife.00248 *equal first author
Tim Grotjohann*, Ilaria Testa*, Marcel Leutenegger*, Hannes Bock, Nicolai T. Urban, Flavie Lavoie-Cardinal, Katrin I. Willig, Christian Eggeling, Stefan Jakobs & Stefan W. Hell (2011) Diffraction-unlimited all-optical imaging and writing with a photochromic GFP, Nature 478: 204-208 doi:10.1038/nature10497 *equal first author
Ilaria Testa, Christian A. Wurm, Rebecca Medda, Ellen Rothermel, Claas Von Middendorff, Jonas Fölling, Stefan Jakobs, Andreas Schönle, Stefan W. Hell, Christian Eggeling (2010) Multicolor Fluorescence Nanoscopy in Fixed and Living Cells by Exciting Conventional Fluorophores with a Single Wavelength, Biophysical Journal 99: 2686 – 2694 doi: 10.1016/j.bpj.2010.08.012
PhD and Postdoc positions available on super resolution light microscopy method development and application to the life science.