Cardiomyocyte sensor responsive to changes in physical and chemical environments

Conventional cardiac physiology experiments investigate in vitro beat frequency using cells isolated from adult or neonatal rat hearts. In this study, we show that various cantilever shapes and drug treatments alter cardiomyocyte contraction force in vitro. Four types of cantilevers were used to compare the contractile forces: flat, peg patterned, grooved, and peg and grooved. Contraction force was represented as bending deflection of the cantilever end. The deflections of the flat, peg patterned, grooved, and peg and grooved cantilevers were 24.2 nN, 41.6 nN, 121 nN, and 134.2 nN, respectively. We quantified the effect of drug treatments on cardiomyocyte contractile forces on the grooved cantilever using Digoxin, Isoproterenol, and BayK8644, all of which increase contractile force, and Verapamil, which decreases contractile force. The cardiomyocyte contractile force without drugs decreased 8 days after culture initiation. Thus, we applied Digoxin, Isoproterenol, and BayK8644 at day 8, and Verapamil at day 5. Digoxin, Isoproterenol, and BayK8644 increased the cardiomyocyte contractile forces by 19.31%, 9.75%, and 23.81%, respectively. Verapamil decreased the contraction force by 48.06%. In summary, contraction force changes in response to adhesion surface topology and various types of drug treatments. We observed these changes by monitoring cell alignment, adhesion, morphology, and bending displacement with cantilever sensors.