Session 2

Molecular Structure and Lipid Ordering at Vesicle–Gold Nanoparticle Interfaces Revealed by SEIRS Spectroscopy

Judith Mihály
on  Mon, 15:10 for  20min
T. Bebesi Farkasné, M. Pálmai, I.Cs. Szigyártó, A. Bóta, Z. Varga, J. Mihály
1. HUN-REN Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, H-1117 Budapest, Magyar tudósok körútja 2
2. Budapest University of Technology and Economics, Department of Physical Chemistry and Materials Science, H-1111 Budapest, Műegyetem rakpart 3
3. Eszterházy Károly Catholic University, Department of Chemistry, H-3300 Eger, Leányka út 12
mihaly.judith@ttk.hu

Abstract

We investigated the molecular structure of lipid-based colloidal dispersions in aqueous media using plasmon-enhanced infrared spectroscopy (SEIRA or SEIRS). Lipid vesicles, representing soft self-assembled nanostructures in liquid phase, serve as model interfaces for studying molecular ordering at curved lipid–water boundaries. By coupling these systems with plasmonic nanostructures like gold nanoparticles (AuNPs) and employing surface-enhanced infrared spectroscopy, we probed vibrational signatures sensitive to interfacial hydration, lipid chain ordering, and local dielectric environment.

Shifts in CH2 stretching vibrations indicate changes in the packing of phospholipid acyl chains, while variations in phosphate and carbonyl vibrational bands reveal electrostatic interactions and modifications in hydrogen-bonding environments at the membrane interface. Furthermore, cooperative aggregation of AuNPs on phospholipid vesicle surfaces leads to localized nanoparticle clustering driven by membrane-mediated interactions, resulting in structural rearrangements. The plasmonic behaviour of aggregated AuNPs plays a critical role in enhancing local electromagnetic fields near the membrane surface, significantly amplifying infrared absorption signals in SEIRS measurements. This enhancement enables highly sensitive detection of subtle conformational and dynamic changes in lipid membranes and interfacial biomolecular interactions that are difficult to observe using conventional IR spectroscopy alone.

The project was supported by the National Research, Development, and Innovation Office of Hungary under grants (K_131657; Advanced_25_152698; Advanced_24_150077; Starting_24_150629).

References

[1] T. Bebesi, M. Pálmai, I.Cs. Szigyártó, A. Gaál, A. Wacha, A. Bóta, Z. Varga, J. Mihály, Colloids and Surfaces B: Biointerfaces, 246, 114366 (2025).