On the electric potentials inside a charged soft hydrated biological tissue: streaming potential versus diffusion...

Area of Science:

• Biomedical Engineering
• Mechanobiology
• Electrokinetics

Background:

• Articular cartilage generates electric fields due to fluid flow and ion transport.
• Understanding these electric fields is crucial for comprehending chondrocyte mechanotransduction and matrix biosynthesis.
• Existing models often simplify the interplay between streaming and diffusion potentials.

Purpose of the Study:

• To determine the nature of electric fields within articular cartilage.
• To investigate the competing effects of streaming potential and diffusion potential.
• To analyze electric field generation under steady permeation and transient confined compression.

Main Methods:

• Solving two-dimensional mechano-electrochemical problems using triphasic theories.
• Modeling steady-state one-dimensional permeation.
• Modeling transient one-dimensional ramped-displacement, confined-compression, stress-relaxation under open circuit conditions.

Main Results:

• Diffusion potential effects compete with streaming potential effects for dominance in electric potential generation.
• In softer cartilage tissues, diffusion potential can dominate, especially during compression.
• Electric potential polarity can be opposite to fluid flow when diffusion potential dominates.
• Across the tissue, electric potential polarity may differ between the inner and outer regions.

Conclusions:

• The interplay between streaming and diffusion potentials significantly influences electric fields in articular cartilage.
• Compression can enhance diffusion potential effects, potentially altering the overall electric field.
• These findings present new challenges for understanding chondrocyte signaling and biosynthesis regulation in response to mechanical loading.