Monitoring Of Mechanical Properties Of H9C2 And Neonatal Rat Primary Cardiomyocytes Using Quartz Crystal Microbalance

The mechanical behavior of cardiomyocytes is closely related to cardiac function,so it is very important to establish accurate and reliable characterization methods of mechanical properties including viscoelasticity and traction in a nondestructive and real-time manner.In this thesis,double resonator quartz crystal microbalance(QCM)technique was used to monitor the mechanical responses of myocardial H9C2 cells of different seeding density(5,000-30,000)during their attachment and spreading onto optically transparent ITO electrodes and the subsequent treatments of inotropic drugs of different concentrations;and the QCM technique was also used for the study of the dynamic changes in mechanical properties of neonatal rat primary cardiomyocytes during their attachment,spreading and beating on to gold electrodes.The main results are as follows:(1)The retractions of both QCM frequency and resistance during the adhesion of 20,000 H9C2 cells were the lowest,and the cell-cell interaction was weak;the surface modification of collagen on ITO electrode promoted cells' adhesion to the modified substrate;under the action of isoproterenol(ISO),H9C2 cells became harder as indicated by larger viscoelastic index(CVI)with larger traction force((35)S),and the magnitudes of increases in CVI and(35)S increased with the increase of ISO concentration;under the action of verapamil(VRP),the cells became softer and the cell traction force became smaller,and the degrees of decreases in CVI and(35)S increased with the increase of VRP concentration.(2)The mechanical responses of neonatal rat primary cardiomyocytes adhered to the surface of gold electrode under the treatments of ISO showed that the cells became harder with larger traction force and were both ISO dose-dependent.And the primary cardiomyocytes of neonatal rats subjected to the treatments of VRP became softer with smaller traction force and were both VRP dose dependent.(3)The changes in viscoelasticity and beating force of beating primary myocardial cells under the treatments of VRP and ISO were also measured.Experimental results showed that for the cells subjected to the treatment of 12.5nM ISO,the fluctuation amplitude of cardiomyocytes' beating force increased,contractile force increased,change in CVI reduced.Whereas under the action of 6.25 nM VRP,the fluctuation amplitude of cardiomyocytes' beating force decreased,relaxation force increased,change in CVI increased,both tensile and contractile stresses became smaller.In summary,QCM technology can: cardiomyocytes and be used for cardiac drug evaluation.