Two spectroscopic techniques, i.e. electron paramagnetic resonance (EPR) and infrared spectroscopy, have been used to systematically study and compare properties of lipid phases in different lipid mixtures. The basis of the EPR approach was the use of a special condensation algorithm for automatic grouping of solutions from multiple simulations of experimental EPR spectra. We have shown that both methods give similar conclusions, which is expected since they have comparable spatial and time scales.
COBISS.SI-ID: 21356071
The knowledge about intermolecular interaction is important for the understanding of the structure of lipid membranes. Our results have confirmed the existence of a direct interaction between cholesterol and lipids with phosphatidylcholine headgroup through hydrogen bonds. We have also found out that the absorption line corresponding to the stretching of carbonyl group reflects phase properties of model membranes. The significance of these results is even higher because the use of the ATR-FTIR enabled measurements on supported membranes in excess water.
COBISS.SI-ID: 21114407
We have investigated supported lipid membranes from sphingomyelin and cholesterol by the ATR-FTIR. We were the first to show that the shape of absorption lines for amide groups reflects coexistence of different lipid phases. We have also examined the existence of hydrogen bonds between sphingomyelin and cholesterol, which might explain the formation and stabilization of lateral heterogeneity in cell membranes, i.e. lipid rafts. Our results have confirmed the presence of hydrogen bonds, which is in agreement with numerical results obtained by molecular dynamics simulations.
COBISS.SI-ID: 21577767
The effect of the composition of small unilamellar vesicles on the formation of supported membranes has been first studied by atomic force microscopy (AFM). Next, we have used scanning near-field IR microscopy (SNIM). This AFM-based method has exceptional resolution of a few tens of nanometers. We have determined the dependence of contrast on the thickness of supported membranes. The SNIM approach is the state of the art, since this method was only developed in recent years. Results were published in the journal Optics Express, which is ranked 2nd in the SCI category Optics.
COBISS.SI-ID: 21716775