Transport of multi-electrolytes in charged hydrated biological soft tissues

A mechano-electrochemical theory for charged hydrated soft tissues with mul tielectrolytes was developed based on the continuum mixture theory. The mom entum equations for water and ions were derived in terms of a mechanochemic al force (gradient of water chemical potential), electrochemical forces (gr adient of Nernst potentials) and an electrical force (gradient of electrica l potential). The theory was shown to be consistent with all existing speci alized theories. Using this theory, some mechano-electrokinetic properties of charged isotropic tissues were studied. The well-known Hodgkin-Huxley eq uation for resting cell membrane potential was derived and the phenomenon o f electro-osmotic flow in charged hydrated soft tissues was investigated. A nalyses show that the tissue fixed charge density plays an important role i n controlling the transport of water and ions in charged hydrated soft tiss ues.