Adaptation of myofibrils to a microstructured polymeric substrate

Myofibrils are functional contractile elements in skeleton and cardiac muscle cells of vertebrates and in skeleton muscle cells of invertebrates. Each myofibril consists of parallel filaments, allowing maximal contraction performance. When these muscle cells are cultured in vitro, this parallel arrangement is often disrupted due to cell remodeling. The contractile performance of the muscle cells is thus deteriorated. In this paper, we present a microstructured polymeric substrate to regulate the reassembly of the myofibrils during cell remodeling. The results show the myofibrils in long-term cultured heart muscle cells are reassembled directionally, along longitudinal axis of the microstructured polymeric sidewalls. This directional arrangement is further validated by monitoring the mechanical performance of the living cells, using embedded polymeric microstructures. This work opens a door for orientation of subcellular elements using microstructured extracellular environments, and is the basis for development of in vitro assembled muscle patches.