The origin of stress-generated potentials in fluid-saturated bone

Area of Science:

• Biophysics
• Biomaterials Science
• Skeletal Biology

Background:

• Bone is a complex composite material.
• Fluid flow within bone's porous structure can generate electrical potentials.
• Understanding these potentials is crucial for bone biomechanics.

Purpose of the Study:

• To determine the primary source of stress-generated potentials (SGPs) in fluid-saturated bone.
• To investigate the influence of fluid properties on SGPs.

Main Methods:

• Cortical bone samples (human and bovine) were saturated with solutions of varying conductivity, NaCl, and sucrose concentrations.
• Macroscopic SGPs and relaxation times were measured.
• Microelectrode measurements were used to assess SGPs as a function of conductivity and NaCl concentration.

Main Results:

• Bone fluid properties significantly impact the magnitude and time-dependence of SGPs.
• High NaCl concentrations consistently reversed the polarity of the SGPs.
• Results align with streaming potential theory.

Conclusions:

• Stress-generated potentials in fluid-saturated bone are predominantly caused by streaming potentials.
• While bone may possess some piezoelectric properties, streaming potentials are the main contributors.
• Fluid composition is a critical factor in bone's electro-mechanical response.