Engineered Fiber Crimp Alters Scaffold Mechanics, Cell Shape, and Strain Transfer to the Nucleus

Introduction Tendons and ligaments are composed of highly aligned collagen fibers that, at the micron-scale, have an intrinsically crimped micro-architecture. With stretch, crimped fibers straighten, resulting in a non-linear mechanical response. Crimp is thus a critical structural adaptation providing function under physiologic strain and is lost with pathological conditions. When such tissues are damaged, one treatment strategy is to engineer replacement tissues using highly aligned arrays of polymer nanofibers, created by electrospinning. Recently, this technique has been further refined to generate fiber crimp by heating scaffolds to their glasstransition temperature. In our previous work, accelerated cellular infiltration was achieved by increasing scaffold porosity with inclusion of a water-soluble sacrificial poly-ethylene oxide (PEO) component. In this study, we increased scaffold crimp by increasing scaffold porosity prior to heating, thus providing increased space for scaffold crimp formation. We then probed the bulk scaffold mechanics and the micromechanical response of both the scaffold and attached cells, identifying differences that will likely regulate mechanotransduction in cells interacting with this material.