3D cardiac cell culture on nanofiber bundle substrates for the investigation of cell morphology and contraction

Cardiac failure is a quite severe condition that can result in life-threatening consequences. Cardiac tissue engineering is thought to be one of the most promising technologies to reconstruct damaged cardiac muscles and facilitate myocardial tissue regeneration. We report a new nanofiber bundle substrate for three-dimensional (3D) cardiac cell culture as a platform to investigate cell morphology and contraction. Polymeric nanofiber bundles with various patterns act as physical cues to align the cardiac cell sheets. Comparing the uniaxial alignment with the randomly distributed pattern, we found that the bundles with the former pattern have more "grooves" for the settlement of cardiomyocytes in a 3D structure than the latter. The cardiomyocytes loaded on the aligned nanofiber bundles tend to grow along the fiber axis. The interfacial structure between a single cardiomyocyte in the cardiac cell sheet and the attached nanofibers was observed using environmental scanning electron microscope. Immunofluorescence imaging showed that the uniaxially aligned nanofibers greatly promoted cell attachment and alignment of the cardiomyocytes because of the matching morphology between the nanofiber pattern and the biological components. Moreover, we concluded that the aligned polymeric nanofibers could be a promising substrate suitable for the anisotropic contraction of cardiac cell sheets.