Experimental study on the coupling between the piezoelectric and streaming potential in wet bone.

The stress-generated potential (SGP) of bone is one of the mechanisms affecting bone remodeling including piezoelectricity and streaming potential. To explore the interactions between the piezoelectric and streaming potential, an experimental setup was designed that simultaneously applied a concentrated force and liquid pressure to wet bone. Using this device, the stress-generated potential of wet bone under the two types of loads was measured. The experimental results show that under a constant liquid pressure, the measured potential curves increase over time, and its increasing rate decrease as the concentrated force increase. The measured peak amplitudes of potential decrease as the liquid pressure increase under the same concentrated force whether loading or unloading. To explain the coupling mechanism of the found phenomena, an equivalent model with two voltage sources and three equivalent resistances was established, and the equivalent electrical relationship between the piezoelectric and streaming potential was obtained by analyzing the model. The analysis discussion implies that various factors have influence on the coupling relationship between streaming and piezoelectric potentials, and the factors can be summarized as the changes of the three equivalent resistances caused by piezoelectric and streaming potentials.