Role of hydration and water structure in biological and colloidal interactions

Short-range repulsions exhibited between the colloidal particles and biological surfaces of water are caused by the entropic repulsion from the confinement of thermally mobile surface groups. This is the reason why water is always a good solvent or suspending medium for colloidal and biological structures such as deoxyribonucleic acid, viruses, proteins and cells. The attractive van der Waals and the repulsive electric double-layer forces are considered to be the major forces that operate between two macromolecules or surfaces in liquids.