A continuum mechanics based framework to quantify local kinematics in electrospun networks for mechanobiological...

Due to their nanostructure closely resembling extracellular matrix, electrospun materials are widely used in tissue engineering and as soft implant materials. While there has been research on their clinical, biological, and chemical biocompatibility, quantitative evaluations of their mechanical biocompatibility are rare. This study addresses this gap by providing a continuum mechanics-based procedure to quantify the inherently inhomogeneous microscale kinematics at the surface of electrospun networks to which biological tissues are exposed. The methodology is developed on the basis of a numerical discrete fiber model and will be applicable to the output of in-situ mechanical tests recorded by scanning electron microscopy imaging and evaluated by digital image correlation. The kinematic quantities comprise the local deformation gradient, its decomposition and related strain tensors, as well as a parameter describing the local planar deformation type. These quantities are summarized in what we call the kinematic fingerprint of the material. Kinematic convergence analyses revealed a material-specific minimum subset size of 10μm for the calculation of local continuum mechanics quantities. Moreover, the size of a material-specific representative surface element, i.e. the minimum region of interest for experimental analyses, was determined as 120×120μm². By addressing the cellular length scale, this study will serve future quantitative investigations in mechanobiology and the mechanical biocompatibility of nanofibrous materials.