| Abstract
| - In recent years, the quartz crystal microbalance (QCM)has been established as a sensitive analytical tool tomonitor the attachment and spreading of mammalian cellsto in vitro surfaces. Due to its superior time resolution,the device is capable of reading even subtle differencesin cell adhesion kinetics. However, thickness shear modepiezoresonators, which are the core component of theQCM approach, can be used not only as a sensor but alsoas an actuator when the oscillation amplitude of the crystalis increased so that molecular recognition at the solid−liquid interface is disturbed. In this study, we haveaddressed the impact of elevated lateral oscillation amplitudes on the adhesion kinetics of three mammalian celllines. We used AT-cut piezoresonators with a fundamentalresonance frequency of 5 MHz, and the analytical readoutwas performed by impedance analysis. Formation ofstable cell−substrate contacts is retarded or entirelyblocked when the lateral oscillation amplitude (in thecenter of the resonator) exceeds values higher than 20nm. Shear oscillations of similar amplitude were, however, not sufficient to displace attached cells from thesurface. Moreover, the experimental data prove that thenormal QCM readout with oscillation amplitudes smallerthan 1 nm is, indeed, non-invasive with respect to mammalian cells.
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