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BP: Fachverband Biologische Physik
BP 10: Computational Biophysics II
BP 10.4: Talk
Tuesday, March 19, 2024, 10:15–10:30, H 0112
Determination of elastic moduli of lipid membranes with improved accuracy: a binning-free approach for lipid height and tilt fields. — •Jonas Paulus1, Friederike Schmid1, and Giovanni Settanni1,2 — 1Department of Physics, Johannes Gutenberg University Mainz, Germany — 2Faculty of Physics and Astronomy, Ruhr University Bochum, Germany
Lipid membranes play a pivotal role in various research domains. This study addresses the need for an improved measurement of the elastic properties of lipid membranes, which can be extracted from the fluctuation spectra of the height of lipids and their orientations. Traditional approaches involve binning the lipids onto a discrete evenly-spaced grid, average their positions and orientation in each bin, and then calculate the spectra by Fourier transform the binned data. However, this method introduces sampling errors and aliasing, due to the uneven distribution of lipids. Here, we first calculate the amplitude of the binning-related inaccuracies and a correction term to mitigate them. Then, we consider a binning-free approach for the fluctuation spectra based on least-square fitting the positions and orientations of lipids with a superposition of wave functions. We show how to cast it into a linear algebra problem involving the computation of a pseudoinverse matrix via singular value decomposition. We show that this approach improves the accuracy of the analysis over those based on data binning and apply it to the characterization of lipid formulations for nucleic acid delivery, computing the effect of pH on their elastic properties.
Keywords: Membranes; Elastic moduli; Molecular dynamics simulations; Lipids