Damage Biomechanics for Neuronal Membrane Mechanoporation

Bakhtiarydavijani, A., Murphy, M. A., Mun, S., Jones, M. D., Bammann, D., LaPlaca, M. C., Horstemeyer, M., & Prabhu, R. (2019). Damage Biomechanics for Neuronal Membrane Mechanoporation. Modelling and Simulation in Materials Science and Engineering. 27, 065004. DOI:10.1088/1361-651X/ab1efe.

In this paper, mechano-physiological damage evolution equations are developed to capture the disruption of neuronal membrane integrity and quantify neuronal cell death in the brain during mechanical insult. Traumatic brain injury (TBI) involves multiscale structure-property relations where the mechanical behavior of the brain is phenomenologically characterized at the macroscale. However, damage largely occurs at the cellular level (microscale and nanoscale) due to the loss of ion homeostasis. To measure this neuronal death mechanism, molecular dynamics simulations were performed on a representative neuronal membrane, a 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) bilayer structures. Pore density and pore growth due to membrane deformation were then quantified. The results showed that the pore growth and pore density rates were a function of stress state, but only the pore growth rate was a function of the strain rate. Mechano-physiological damage evolution equations were developed to capture the damage biomechanics of the POPC bilayer based on the pore density and growth rate responses. The proposed damage evolution equations were combined with the Nernst-Planck diffusion equation to produce a criterion based on the change of intracellular calcium ion concentration.