The electric double layer in bone and its influence on stress-generated potentials.

Stress-generated potential (SGP) studies in fluid-filled bone have been interpreted in terms of streaming potential theory. Variations in fluid conductivity and viscosity are in agreement with this theory. Experimental results also indicate that the zeta potential of bone is dependent upon the ion concentration of the fluid. In fact, the zeta potential is seen to reverse polarity at sufficiently high concentrations of NaCl and KCl. This observation indicates that the electric double layer at the fluid-bone matrix interface is an important region contributing to electromechanical effects in bone. The double layer may also have an effect on piezoelectric studies in dry bone since the charged species remain on the matrix after the bone specimens are dried.