Dresden 2020 – scientific programme

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BP: Fachverband Biologische Physik

BP 25: Cell Mechanics II

BP 25.2: Talk

Wednesday, March 18, 2020, 15:15–15:30, HÜL 386

Investigating the red blood cells (dis)aggregation mechanism using optical tweezers — •Francois Yaya^1,2, Olivera Korculanin³, Mehrnaz Babaki³, Kisung Lee⁴, Pavlik Lettinga^3,5, and Christian Wagner¹ — ¹1Experimentalphysik, Saarbrücken, Germany — ²Interdisciplinaire de Physique, Grenoble, France — ³ICS-3 Forschungszentrum, Jülich, Germany — ⁴Korean Institute for Basic Science, Ulsan, South Korea — ⁵Laboratory for Soft Matter and Biophysics, KU Leuven, Belgium

Red blood cells (RBC) in our body circulate, while continuously aggregating and disaggregating under low shear rates. RBC aggregation is a reversible process that can only be observed in the presence of macromolecules (i.e. large plasma proteins like fibrinogen or non-ionic polymers). The potential description of the RBC interaction was studied, mainly from the scope of polymer induced aggregation and predominantly with dextran. Despite the favored model based on the depletion forces, one can find that, conclusive experimental affirmations of the model are still lacking. Hence, we aimed to investigate the RBC interaction mechanism utilizing holographic optical tweezers (HOT). We assessed RBC interaction forces in two model solutions, namely dextran and a pure depletant (Fd virus). Aggregation and disaggregation of multiple pairs of RBC, in dextran, revealed that forces differ by more than 3 fold. For Fd virus, interaction forces are in the same order of magnitude. Combining HOT with a microfluidic platform, we finally show that adsorption of macromolecules takes place onto a single RBC membrane.