An alternative approach to characterize the strength of the interfacial hydrogen bond network in suspensions of zwitterionic or anionic lipids

Petko, Ramona; Pem, Barbara; Bakarić, Danijela (2027) An alternative approach to characterize the strength of the interfacial hydrogen bond network in suspensions of zwitterionic or anionic lipids. Fluid Phase Equilibria, 611 . ISSN 0378-3812

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Abstract

Characterizing the strength of the hydrogen-bond (HB) network at the lipid bilayer interface is crucial for understanding water's role at the cell membrane surface. To achieve this, we examined lipid suspensions using linear FTIR spectroscopy and refractive index measurements, complemented with MD simulations. The temperature-dependent FTIR spectra of lipid suspensions were examined in the spectral region in which only the water combination band appears (2650–1800 cm–1). Assuming that water exists in two microstructures - high-density and low-density - whose populations alternate with temperature, the examined combination band was represented as projections of two components, whose concentration profiles were subjected to second-degree polynomial regression. The curvature coefficient of the concentration profiles differs between anionic 1,2-dipalmitoyl-sn-glycero-3-phosphatidylglycerol (DPPG) and zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) lipids, correlating with the HB network strength. Our findings align with independent refractive index measurements, showing that DPPG lipids exhibit higher polarizability and lower fluctuations in a HB network due to stronger HBs with water compared to DPPC lipids. This simplified approach facilitates the characterization of the HB network around lipid bilayer interfaces, offering a more realistic model of plasma membranes than lipid monolayers.

Item Type:	Article
Uncontrolled Keywords:	1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC); 1,2-dipalmitoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DPPG); Transmission temperature-dependent FTIR spectroscopy; Chemometrics; Refractive index (n(λ)) and molecular polarizability (α); Molecular dynamics (MD)
Subjects:	NATURAL SCIENCES NATURAL SCIENCES > Chemistry NATURAL SCIENCES > Chemistry > Physical Chemistry
Divisions:	Division of Organic Chemistry and Biochemistry
Projects:	Project title Project leader Project code Project type Model demijelinizacije na molekulskoj skali pri fiziološkim i patološkim uvjetima-DEMYMOLSCALE Danijela Bakarić UIP-2020-02-7669 HRZZ A New Approach in the Structural Characterization of Drug Delivery Systems Danijela Bakarić NoStruDos PoC
Depositing User:	Danijela Bakarić
Date Deposited:	29 Jun 2026 13:46
URI:	https://fulir.irb.hr:/id/eprint/12021
DOI:	10.1016/j.fluid.2026.114807

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