Regensburg 2022 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 3: Cell Mechanics 1

BP 3.9: Vortrag

Montag, 5. September 2022, 12:00–12:15, H15

Measuring the Tension of Droplets and Living Cells with the Scanning Ion Conductance Microscope — •Johannes Rheinlaender and Tilman E. Schäffer — Institute of Applied Physics, University Tübingen, Germany

It is well known that surface tension can dominate the mechanics of micro- and nanoscale systems. However, probing the mechanics of elastic interfaces at the micrometer scale can be difficult because of the complex probe-sample interactions or the unknown underlying geometry. Here, were introduce a method to measure the surface tension of interfaces at the micrometer scale in a contact-free manner using the scanning ion conductance microscope (SICM). The SICM is based on recording the ion current through a nanopipette and was recently extended to also measure the mechanical stiffness of soft samples utilizing a microfluidic flow through the nanopipette opening. By measuring the three-dimensional shape and mechanical stiffness of oil droplets on various surfaces, we show that we can quantitatively measure their surface tension independently of their shape over more than three orders of magnitude. Applying this concept to living cells, we show that we can quantitatively measure their local stiffness and average (cortical) tension in a contact-free way. Living cells exhibit cortical tensions on the order of few mN/m, which we found to strongly vary with cell type and external conditions. For example, we show that normal and cancer cells strongly differ in their cortical tension, which demonstrates that the SICM is a versatile tool to measure the mechanical properties of living cells.