Long-term Fates of Reversibly Sonoporated Cells Dependent on Degree of Intracellular Calcium Fluctuations

The short- and long-term fate of the reversibly sonoporated cells dominate the efficiency and bio safety of sonoporation-based drug delivery. A customized live cell imaging device and ultrasound exposure system were used to elicit ultrasound exposure and real time tracing cell fate after sonoporation. The intracellular calcium fluctuations (ICF) of sonoporated cells were categorized into three groups, low ICF (<70), moderate ICF (70-140) and high ICF (>140). The proportion of sonoporated cells undergoing proliferation gradually decreased from ~77.1% (low and moderate ICF) to 64% (high ICF) while that of the cells undergoing death gradually increased from ~14.3% (low and moderate ICF) to 24% (high ICF). Moreover, the surviving time of the reversibly sonoporated cells decreased from 11.5 h (low ICF) to 4 h (high ICF). Finally, the sonoporated cells undergoing cell cycle arrest within the first 24 h went to different fates in the next 24 hour (from 24 h to 48 h post-exposure). With the increasing ICF, the probability of arrested cells moving towards to survival decreased from 75% (low ICF) to 41.7% (high ICF), and toward to death increased from 0% (low ICF) to 33.3% (high ICF). These results showed that intracellular calcium fluctuation was a crucial factor determining the long-term fates of sonoporated cells.