SKM 2023 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: Polymer and Molecular Dynamics, Friction and Rheology

CPP 20.2: Vortrag

Dienstag, 28. März 2023, 10:00–10:15, ZEU 255

Phase-Sensitive, Active Microrheology via Probe-Free Application of Thermoviscous Flows — •Iliya Stoev, Elena Erben, Venkat Krishnaswamy, Antonio Minopoli, Susan Wagner, Benjamin Seelbinder, Nicola Maghelli, and Moritz Kreysing — Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany

We recently found how thermoviscous expansion phenomena give rise to a new, contactless particle trap that is characterised by a linear force-extension relationship and can therefore be employed in non-invasively measuring femtoNewton forces with thermally limited sensitivity. Our new force-measurement method is based on optically generated flows, thereby lifting prerequisites related to the probe material and resulting in only moderate heating at the position of the micromanipulated object. This methodology offers an appealing alternative to the use of optical tweezers in highly delicate samples and living systems. Next, we asked the question if our thermoviscous flows can be used to obtain more quantitative data and possibly demonstrate the equivalence between flow-driven and force-driven rheology in their ability to extract phase angles as a measure of relative mechanics. With our new flow-based and phase-sensitive microrheology, we provide access to the mechanics of highly viscous media, tenuous gels and even cellular cytoplasm. Further refinements of the method aim at multiplexing and removing the need for using fluorescent tags.