Monitoring of cultured cell activity by the quartz crystal and the micro CCD camera under chemical stressors

For investigating effects of chemical stressors to cultured cells, we have developed a quartz crystal microbalance (QCM) system with a micro CCD camera that enables microscopic observations simultaneously with the QCM measurements. Human hepatoma cell line (HepG2) cells were cultured on the collagen coated quartz crystal which has indium tin oxide (ITO) electrodes that enable transmission imaging of the cultured cells by the micro CCD camera during the QCM measurements. Glutaraldehyde (GA) and t-butylhydroperoxide (t-BHP) were used for the chemical stressors. The response of the QCM was monitored and analyzed with the resonance frequency and the resonance resistance (F–R) diagram. At the same time, the photographs of the cells were recorded to observe the morphological change. In the case of GA, the QCM responded in two steps which consisted of the rapid response of the cross-linking reactions and successive decreasing cytoskeletons in the cells. In the case of t-BHP, the response showed two steps. At first, the cells changed their shapes to round, and then the weakened cells were unsticked from the surface.