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Vorträge und Posterpräsentationen (ohne Tagungsband-Eintrag):

P. Kramar, K. Balantic, F. Castellani, T. Vernier, V. Weiss, G. Allmaier, D. Miklavcic:
"Effect of calcium ions on the cell membrane models";
Vortrag: XXV International Symposium on Bioelectrochemistry and Bioenergetics, Limerick; 26.05.2019 - 30.05.2019.



Kurzfassung englisch:
Calcium electroporation is a new experimental anti-cancer treatment where calcium is internalized into cells by application of short, high voltage pulses. The anti-tumour effectiveness has been demonstrated in vitro, in vivo and in clinical studies as well as effect on vasculature has been explored [1,2]. However basic physical principles of calcium ions on the cell membrane is not fully elucidated. The aim of the study was to introduce the calcium ions to the simplified and controllable models of cell membrane such as computer Molecular Dynamics simulation (MD), and experimental planar lipid bilayers and liposomes. The results of each model can be analysed and compared. In all of the investigated models CaCl2 were added in a buffer solution on one side of the membrane. Results of molecular dynamics simulating POPC membrane shows binding of calcium ions to the lipid headgroups and decreasing of the area per lipid [3]. Experimentally measured capacitance on planar lipid bilayers increases due to adding CaCl2 into a buffer solution in steps of 0.5 mM from 0 to 5 mM. Experiments on liposomes were performed using gas phase electrophoresis to evaluate the diameter of the prepared vesicles [4]. Diameters of the vesicles were measured in buffer of 40 mM ammonium acetate and the same buffer with added CaCl2. Results show that diameter of vesicles reduces with added calcium ions by about 12% measured at the peak apex of fitted Gauss peaks. Three simplified models of cell membrane were studied. MD simulation results of capacitance increase are in agreement with planar lipid bilayer experiments. This increase of planar lipid bilayer capacitance results from calcium ion binding on the lipid headgroup. Also, the reduction of diameter of the vesicles experiment are in agreement with the area per lipid value calculated from MD simulations.



[1] S.K. Frandsen, J. Gehl, PLoS One. 12 (2017) 1-12.
[2] B. Staresinic, T. et al., Sci. Rep. 8 (2018) 1-14.
[3] F. Castellani, P.T. Vernier, BioEM 2018, Piran, Portoroz, Slovenia, June 2018.
[4] V.U. Weiss et al., Analyst. 141 (2016) 6042-6050.

Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.