Cryogenic microscopy of protein complexes at angstrom resolution & three-dimensional fluorescence-free imaging and tracking in live cells

Date

Jan 26, 2026

Time

11:15 AM - 12:15 PM

Speaker

Vahid Sandoghdar

Affiliation

Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin Erlangen, Germany

Language

en

Main Topic

Biologie

Host

Stephan Grill

Description

Fluorescence microscopy has been the workhorse of biological microscopy in the last half a century, also leading to super-resolution microscopy. In the first part of this presentation, I will discuss the application of cryogenic fluorescence microscopy for improving the photophysics of fluorophores, thus, allowing us to reach three-dimensional angstrom resolution in resolving several sites of a single protein or protein complex. While fluorescence labeling remains a powerful tool, it poses fundamental limitations, which have motivated many groups to develop fluorescence-free measurement methods. Among various contrast mechanisms, scattering offers unique opportunities. About two decades ago, we showed that single gold nanoparticles as small as 5 nm could be detected via interferometric detection of their scattering, coined iSCAT. Since then, it has been shown that unlabeled nano-objects such as proteins and viruses as small as 10 kDa can be detected, counted and tracked. We will discuss the application of this method in characterizing extracellular vesicles and cellular secretomes. Furthermore, I will present our most recent results on three-dimensional label-free imaging of cellular events such as the endoplasmic reticulum and microtubule dynamics as well as virus diffusion via confocal iSCAT microscopy. In addition to our iSCAT work, I plan to present an efficient method for delivery of nanoparticles and small molecules to well-defined positions on a cell.

Last modified: Jan 26, 2026, 7:36:59 AM