Berlin 2024 – scientific programme
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BP: Fachverband Biologische Physik
BP 9: Poster Session Ib
BP 9.12: Poster
Monday, March 18, 2024, 18:00–20:30, Poster D
Virtual fluidic channels as liquid tweezer for mechanocytometry — •Karolin Melde1, Doreen Biedenweg1, Salvatore Girardo2, Horst-Holger Boltz1, Thomas Ihle1, and Oliver Otto1 — 1Institute of Physics, University of Greifswald, Greifswald, Germany — 2Max Planck Institute for the Science of Light, Erlangen, Germany
Real-time deformability cytometry is a high-throughput method to study the mechanical properties of single cells. Utilizing hydrodynamic shear and normal stresses, micron-sized objects are deformed within a microfluidic channel of dimensions that have to match the cell size.
To overcome this limitation, we recently introduced virtual fluidic channels (VFCs) that enable tailoring the microfluidic geometry within seconds. VFCs are formed by co-flowing aqueous polymer solutions, where cells are confined between the corresponding liquid-liquid interfaces that act as a pair of tweezers. Interestingly, these liquid tweezers impose a normal stress on cells that cannot be understood from bulk interfacial tension, but that is sufficient to induce cell deformation.
Here, we aim to study the physics of this liquid-liquid interface by introducing calibration particles in the form of oil droplets and hydrogel beads. While the latter possess a Young’s modulus of 1.4 - 1.6 kPa, the surface tension of the oil droplets was characterized using a ring tensiometer. Preliminary experiments show that both particles can be deformed by the pair of liquid tweezers. We plan to build upon these initial results and examine the impact of different flow rates and polymer compositions on interfacial stability and stress.
Keywords: Real-time deformability cytometry; Virtual fluidic channel; Interfacial stress; Cell mechanics; Microfluidics