Contractile behaviors of cardiac muscle cells on mushroom-shaped micropillar arrays

In this work we propose mushroom-shaped PDMS (Polydimethylsiloxane) mu pillar arrays for enhancing the contractile force of cardiomyocytes during cell culturing. Conventional micropillar (mu pillar) arrays with flat surfaces were employed as a standard sample to quantitatively recognize experimental data and to conclusively demonstrate the improved performance of mushroom-shaped PDMS mu pillar arrays. Cardiomyocytes isolated from experimental animals were cultured on both of the fabricated mu pillar arrays and then monitored over a growing period. Deflections of mu pillars were precisely measured through a home-built analyzing system quantitatively representing the contractile force of cardiomyocytes. Mushroom-shaped PDMS mu pillar arrays exhibited a 20% improved contractile force compared to conventional PDMS mu pillar arrays due to their topographical dependency. Preliminary results also show that the proposed mushroom-shaped PDMS mu pillar surface positively affects the Z-band width, actin filament polymerization and focal adhesion (FA) of cardiomyocytes. Further, the enhanced performance of mushroom-shaped PDMS mu pillar arrays was confirmed by measuring the cardiac sarcomere alpha-actin length and myofilament width via ICC (immunocytochemistry) staining and western blot experiments.