Effect of 2D-WS₂ Nanoparticles on a Local Electrical Field at a Membrane Vicinity: Vibrational Spectroscopy Data

Fourier-transform infrared (FTIR) spectral changes for model membranes (liposomes) consisting of three lipids, 1,2-dioleoyl-sn-glycero-3-phosphocholine, cardiolipin, and cholesterol, were studied under the application of 2D-WS2 nanoparticles during the process of liposome preparation and after it. We got up to a 30% increase in the intensity of lipid vibrational bands for PO2-stretching symmetrical vibrations and 10% for CH2- and OH-stretching vibrations in the case of liposomes prepared without nanoparticles and after their subsequent addition. The changes in FTIR spectra are explained by the local electrical field appearing in liposomes, which are placed in the vicinity of the curved 2D-WS2 nanoparticles. Quantum-chemical calculations showed negligibly small changes in electron density and Bader charges (less than 0.02 e) of the single-layer 2D-WS2 corrugated up to 10%. Inhomogeneous charge distribution at the liposome surface can enhance the electron density of the 2D-WS2 nanoparticles leading to the redistribution of FTIR spectra intensity for liposomes near the 2D-WS2 nanoparticles.