Lucie Pigeon*1, Anthony Delalande*2,3, Spiros Kotopoulis2,3, Michiel Postema3, Patrick Midoux1, Chantal Pichon1
1Centre de Biophysique Moléculaire, CNRS UPR4301 and Université d’Orléans, France; 2Haukeland hospital, Bergen, Norway, 3Department of Physics and Technology, University of Bergen, Bergen, Norway
Upon ultrasound (US) exposure, gas microbubbles (MB) can be expanded, moved and even destroyed. These properties offer the opportunity of site-specific local drug/gene delivery. A key to success of this technique lies in understanding the mechanisms governing microbubblecell interactions. Here, we performed real time experiments of sonoporation to investigate how MB under US behave towards cells in optimal conditions that allow an efficient gene transfer. Studies were performed on a specific set-up composed of sonoporation chamber mounted on a fluorescence confocal microscopy coupled to a high-speed camera. Data show for that MB can be pushed and subsequently enter the cell during the sonoporation process. MBs were attached in lipid rafts as shown by their colocalization with cholera toxin B subunit marker. Interestingly, sonoporation affect the chromatin structure. This effect was observed with HeLa cells coexpressing histone H2B tagged to either EGFP or mCherry. FRET experiments clearly show that chromatin condensation was affected after cell treatment with US alone and this is enhanced in presence of MB.