Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 17: Poster V
BP 17.3: Poster
Dienstag, 17. März 2020, 14:00–16:00, P2/1OG
Observing polymer conformations at the 2D theta point — •Julian M. Philipp1, Joachim O. Rädler1, and Eugene P. Petrov2 — 1LMU, Munich, Germany — 2PTB, Berlin, Germany
Important biological processes at cellular membranes involve interaction of biopolymers with the elastic deformable lipid bilayer. It has been found previously that conformations of DNA macromolecules adsorbed to freestanding cationic lipid membranes are controlled by the DNA-membrane attraction: whereas at low membrane charge densities membrane-bound DNA molecules behave as 2D swollen chains, an increase in the DNA-membrane attraction leads to membrane-driven coil-globule transition [1, 2]. These two regimes should be separated by the theta point, at which electrostatic and steric repulsion and membrane-mediated attraction of polymer segments compensate each other. Although theoretical predictions for the scaling of the macromolecule dimensions at the 2D theta-point are known [3]: Rg ∼ L4/7, the 2D theta-point behavior has never been observed directly in experiments. Using fluorescence microscopy we study conformations of single DNA molecules on freestanding cationic lipid bilayers at the membrane compositions close to those inducing the coil-globule transition and find that the dependence of Rg on L follows the scaling predicted for polymers at the theta-point in 2D. This represents the first direct experimental observation of polymer conformations at the 2D theta point. [1] C. Herold, P. Schwille, E.P. Petrov, Phys.Rev.Lett. 104(2010)148102; [2] A.G. Cherstvy, E.P. Petrov, Phys.Chem.Chem.Phys. 16(2014)2020; [3] B. Duplantier, H. Saleur, Phys.Rev.Lett. 59(1987)539.