Electromechanical coupling in fascia and its link to collagen morphology.

Fascia forms a continuous connective tissue network throughout the body and is persistently subjected to complex mechanical loading, including stretching, compression, shear and torsion during daily activity. Growing evidence suggests that fascia is not merely a passive mechanical linkage for force transmission but may also participate in diverse physiological processes, implying its functional versatility. Such multifunctionality is likely governed by the coupling of multiple factors, yet the underlying biophysical properties remain incompletely understood. Here, we performed a systematic investigation of dried ex vivo fascial tissues from multiple anatomical regions of rats in two age groups (1-2-month and 12-month) using Piezoresponse Force Microscopy. We demonstrate that fascia exhibits measurable electromechanical coupling and that the effective piezoelectric coefficient is significantly higher in the 12-month group than in the 1-2-month group, whereas differences among anatomical regions within the same age group are comparatively small. Integrating the experimental observations with theoretical analysis suggests that the stronger effective electromechanical response may be associated with the presence of thicker collagen fiber bundles, and that the inclination angle of collagen bundles may also contribute to the overall effective electromechanical response. Together, these findings confirm the electromechanical coupling of fascia and link its magnitude to collagen morphology, providing a biophysical basis for understanding the multifaceted roles of fascia in physiological function and for addressing clinically relevant conditions associated with fascial morphological alterations.