Relationship of Salt Disparity and Its Consequence for Swelling in Biological Gels

New irreversible thermodynamic relationships are derived which explain why biological tissues tend to swell. In the course of their derivation, fresh concepts arize. In particular, the relationship of salt disparity is described which forbids diffusible salt generated chemical and osmotic potentials to be simultaneously at equilibrium in the presence of ionized macromolecules. This relationship is developed to generate a new intrinsic thermodynamic property which is termed gel pressure and which drives fluid flows.