Water as a Link between Membrane and Colloidal Theories for Cells

Abstract

This review is an attempt to incorporate water as a structural and thermodynamic component of biomembranes. With this purpose, the consideration of the membrane interphase as a bidimensional hydrated polar head group solution, coupled to the hydrocarbon region allows for the reconciliation of two theories on cells in dispute today: one considering the membrane as an essential part in terms of compartmentalization, and another in which lipid membranes are not necessary and cells can be treated as a colloidal system. The criterium followed is to describe the membrane state as an open, non-autonomous and responsive system using the approach of Thermodynamic of Irreversible Processes. The concept of an open/non-autonomous membrane system allows for the visualization of the interrelationship between metabolic events and membrane polymorphic changes. Therefore, the Association Induction Hypothesis (AIH) and lipid properties interplay should consider hydration in terms of free energy modulated by water activity and surface (lateral) pressure. Water in restricted regions at the lipid interphase has thermodynamic properties that explain the role of H-bonding networks in the propagation of events between membrane and cytoplasm that appears to be relevant in the context of crowded systems.

The biophysics of water in cell biology: perspectives on a keystone for both marine sciences and cancer research

“…Investigations on water properties in membrane interfaces ( Disalvo et al, 2008 ) have progressively led to seeing water as a structural and thermodynamic component of biomembranes ( Disalvo et al, 2022 ). Given the impact of the crowding effect on the thermodynamics of metabolic reactions, the way water shapes proteins was recently documented, revealing its role in protein stabilization ( Crilly et al, 2021 ).…”

Lamellarity-Driven Differences in Surface Structural Features of DPPS Lipids: Spectroscopic, Calorimetric and Computational Study

“…However, as soft and deformable supramolecular structures of high charge density, their response to the exposed stimulus strongly varies with the electromechanical properties of the bilayer [ 24 , 25 , 26 ], along with the composition and amount of the aqueous medium in which the lipids are suspended [ 26 , 27 , 28 ]. The instantaneous morphological alterations such as surface curvature fluctuations of DPPS-constituted lipid membrane [ 29 ] may drive the local pH change and occasional (de)protonation of carboxylic groups ( Figure 1 ) that primarily depend on the inherent bilayer curvature and associated elastic constants [ 25 , 26 , 29 ].…”

Aquaphotomics—Exploring Water Molecular Systems in Nature

“…Out of the 21 published articles, 3 were reviews [ 2 , 3 , 4 ] and 18 were original research papers [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], that can be roughly separated into 6 categories ( Figure 3 ).…”

“…This is exactly something that can be said about the category of material science [ 7 , 16 ], a relatively new area where aquaphotomics is slowly starting to make progress. The last two categories, cell biology [ 3 , 20 ] and diagnostics and therapy [ 11 , 19 ], do not feature many research papers because of the difficulty of conducting research with living systems. However, these two categories, and perhaps life science in general, still represent an important direction of growth that holds the strongest potential for making an impact and lasting change in our world, by transforming the current practices and offering non-destructive, real-time monitoring and early diagnostics that hopefully one day will be replaced with prevention.…”

“…Two more papers of this Special Issue report interesting new theories and findings in cell biology. First, the review paper by Disalvo et al [ 3 ] focused on the role of water in biomembranes, the structures commonly thought as surrounding and protecting the cells. In this review, the authors strongly and persuasively present evidence that water should be considered a structural and thermodynamic component of membranes and suggests incorporating this into current theories about the role of membranes in cells.…”