Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 28: Single Molecule Biophysics
BP 28.11: Vortrag
Donnerstag, 15. März 2018, 12:30–12:45, H 1058
Visualizing cellular secretion dynamics with single protein sensitivity — •Katharina König1,2, André Gemeinhardt1, Matthew P. McDonald1, and Vahid Sandoghdar1,2 — 1Max Planck Institute for the Science of Light, Erlangen — 2Friedrich Alexander University Erlangen-Nuremberg, Erlangen
Cellular secretion of proteins and exosomes into the extracellular environment is an essential mediator of critical biological mechanisms, including cell-to-cell communication, immunological response, targeted delivery, and differentiation. Here, we report a novel methodology that allows for the real-time detection and imaging of single unlabeled proteins and exosomes that are secreted from individual living cells. This is accomplished via interferometric detection of scattered light (iSCAT), and is first demonstrated with human B cells that are found to actively secrete IgG antibodies at a rate of ca. 100 molecules per second. Importantly, iSCAT signals can be measured at extremely high speeds (up to MHz for small nanoparticles), enabling the measurement of single cell secretion dynamics with sub-second temporal resolution and single protein sensitivity. Such experimental capabilities are unmatched by any contemporary proteomic method. We furthermore show the generality of the technique through the study of T cell cytokine secretion, Leishmania parasite exosome release, and single-cell lysate analysis. Our results establish iSCAT imaging as a powerful label-free tool for studying the real-time exchange between cells and their immediate environment with single protein sensitivity.