In vitro transfer of antisense oligodeoxynucleotides into coronary endothelial cells by ultrasound

Since antisense oligodeoxynucleotides (AS-ODNs) have been recognized as a new generation of putative therapeutic agents, we established a delivery technique that could transfect AS-ODNs, which are designed for endothelin type B receptor (ETB), into cultured human coronary endothelial cells (HCECs) by exposure to ultrasound in the presence of echo contrast microbubbles. Ultrasound offers several advantages such as being nontoxic, nonantigenic and providing rapid gene transfer. We standardized the optimal conditions, which consisted of 2 x 10(6) cells suspended in phosphate buffer with 900nM ODN, 50 microl of echo contrast microbubbles (Optison), and ultrasound exposure (1.0 W/cm(2), 10% duty cycle, and 10s duration). The percentage of transfected cells was 25.2+/-2.0% after ultrasound treatment. This is the first demonstration of the use of the ultrasound exposure technique in conjunction with microbubbles in HCECs.