Finite Element Analysis of Axonal Microtubule Bundle under Tension and Torsion

Microtubule bundles cross-linked by tau proteins are essential in many functions of neurological tissues, axons for instance, and play a fundamental role in keeping their mechanical integrity, facilitating their growth, and help promoting cargo transport. Damages resulted from Traumatic Brain Injuries (TBIs), lead to disorientation of these bundles and impose some cognitive damages to the patient as well as shortening the operability of axons themselves. This study shows that axonal microtubule bundle cross-linked by tau proteins under a uniaxial tension and torsion, which is, to our knowledge, the first 3D finite element model to investigate mechanical properties of axonal microtubule bundle. The results show strain-stiffening behavior of these bundles under uniaxial tension. We also investigated the behavior of each bundle under torsional loading and derived modulus of rigidity for each cross-link spacing bundle which may shed light on making neurological scaffolds as we may have more realistic model and will be able to select materials with mechanical properties with better agreement with that of the real tissue.