Journal Article

Insights on Hydrogen Bond Network of Water in Phospholipid Membranes: An Infrared Study at Varying Hydration

Ciccolo, Andrea, D’Angelo, Giovanna, Branca, Caterina, Wanderlingh, Ulderico, Verduci, Rosaria, Bonaccorso, Elisa, Conti Nibali, Valeria

2025

Overview

Water in membrane interphases is vital for cellular biological functions, but despite its importance, the structure and function of biological water remain elusive. Here, by studying the OH stretching mode in partially hydrated lipid multilayers by FTIR measurements, relevant information on the water structure near the surface with lipid membranes has been gathered. The water hydrogen bond network is highly perturbed in the first layers that are in contact with the lipid membrane, exhibiting strong deviations from tetrahedral symmetry and a significant number of defects, such as isolated water molecules and a large number of hydrogen-bonded water dimers in the interphase region. These findings support the hypothesis that water chains form in phospholipid membranes, and are involved in the proton transfer across lipid bilayers by phosphate groups of opposing lipids. Furthermore, we have determined that even at very low hydration levels, a small amount of water is embedded within the confined spaces of the hydrocarbon region of phospholipid bilayers, which could potentially contribute to the structural stability of the lipid membrane.

• Publisher: MDPI AG,MDPI
• Subject: Cellular structure / Confined spaces / Dehydration / Fourier transforms / FTIR attenuated total reflection spectroscopy / Humidity / Hydration / Hydrogen / Hydrogen bonding / Hydrogen bonds / Interfaces / Lipid bilayers / Lipid membranes / Lipids / membrane hydration / Membranes / Moisture content / Multilayers / phase transition / Phosphates / phospholipid membrane / Phospholipids / Proteins / Structural stability / Structure-function relationships / Water / Water chemistry / Water content