Cavitation effect in some erythrocyte suspensions

The destructive effects of ultrasound on cell suspensions depend on the parameters of the ultrasonic field and the experimental conditions. Erythro-cytes of three origins were investigated: frog, chicken and rat. The frequency of the ultrasound was 1 MHz, with the intensity ranging from 0.4 to 1.2 Wcm-2. The volume concentrations of the samples were in the range 0.5-2 per cent. The investigation determined the volume concentration limit at which, at a suf-ficiently high field intensity, the destructive effect may be produced.
In well defined conditions (at sufficiently low concentration) cavitation occurs, which has destructive effects (haemolysis). Haemolysis is produced at a well defined concentration in each case, depending on the physical, chemi¬cal and biological properties of the erythrocytes. The threshold concentration varies for different erythrocytes; thus the following values were obtained at 0.4 Wem-2: chicken 0.5 per cent, frog 1 per cent, rat 2 per cent. At low inten-sities (J = 0.4 Wcm-2), high frequency, short duration and diluted suspens-ions, cavitation plays a mayor role in the haemolysing action.