Effect of high-energy shock wave frequency on viability of malignant cell lines in vitro

In this study, the effects of high-energy shock wave (HESW) frequency on the viability of three different malignant cell lines were evaluated using a piezo-electric generator. The cell lines studied were AR42-J, VX-2 and HeLa. These cells were targeted both in free suspension and immobilised in gelatine beads. All cell lines in free suspension were acutely sensitive to HESW over a range of frequencies. When cells were immobilised in gelatine, however, the effect on cell viability was not as pronounced. However, at frequencies of 80- and 160-Hz kill rates approaching 80 and 90%, respectively, were observed. Cell proliferation following HESW treatment was not adversely affected. This study demonstrates that single cell suspensions are not appropriate for assessing the in vitro cellular effects of HESW. However, even when cells were immobilised in gelatine, high-frequency HESW produced substantial kill rates. The effects of high-frequency HESW merit further evaluation particularly using in vivo tumour.