Experimental study of the effects of Optison (R) concentration on sonoporation in vitro

Lethal sonoporation and reparable sonoporation were observed in Jurkat lymp hocytes in suspension with the addition of varying amounts of Optison(R), a commercially available bubble-based contrast agent. For given ultrasound ( US) exposure conditions (spatial peak-pressure amplitude of 0.2 MPa, duty c ycle 10% and 2-MHz frequency), sonoporation was directly related to the bub ble-to-cell ratio (in a range from 0 to 230), It was found that the nearest bubble-cell spacing was also related to the occurrence frequency of bioeff ects, A constant bubble-to-cell ratio often provided very different results for two different initial cell concentrations (200,000 cells/mL and 600,00 0 cells/mL), with the higher cell concentration generally exhibiting higher levels of sonoporation. In contrast, a constant bubble-to-cell spacing pro vided similar results between the two initial cell concentrations, The freq uency of reparable and lethal sonoporation was seen to decay as the inverse -cube power of the nearest bubble-cell spacing. Significant reparable sonop oration was observed at a bubble-cell spacing that was 10 mum larger than t he minimum spacing at which significant lethal sonoporation was observed. P reliminary analysis also suggests the possibility of a step-wise increase i n lethal sonoporation as spacing decreases; further experiment is needed. ( C) 2000 World Federation for Ultrasound in Medicine & Biology.