Local properties of oriented tissues – you can still use indentation!

Microindentation is a useful technique for assessing the local properties of soft materials. But applying an appropriate contact model and extracting those properties is a more complex matter, especially for anisotropic biological tissues like tendon. Do not despair! Jiho worked with the Wagoner Johnson Lab to demonstrate the elliptical contact areas between a spherical probe and oriented tendon samples through a unique transfer stamping technique. The minor axis of the ellipse is the dimension of less deformation, so that is the axis of orientation of the collagen fibrils that make up the tendon. These measurements help to validate a combined simulation and analytical technique to calculate the stiffness in different directions along the sample. Give it a go, here’s the paper!