Enhancement of ultrasonically induced cell transfection with artificial cavitation nuclei

Ultrasound mediated gene transfection in cultured immortalized human chondrocytes was enhanced three-fold using artificial cavitation nuclei in the form of Albunex(R). 1.0 MHz ultrasound transmitted through the bottoms of six-well culture plates containing media with green fluorescent protein reporter gene plasmids at a concentration of 40 μg/ml and Albunex(R) at 50×10⁶ bubbles/ml, exhibited a peak transfection efficiency of about 50% of the living cells when exposed to 4×10⁵ Pascals spatial average peak pressure (SAPP) for 20 minutes. Using these parameters, transfection efficiency increased linearly with ultrasound exposure pressure with a transfection threshold observed at a SAPP of 10⁵ Pascals. Adding fresh Albunex(R) at 50×10⁶ bubbles/ml prior to sequential one second 3.2 or 4.0×10⁵ Pascal exposures increased transfection efficiency by 15% for each of three consecutive exposures. Efficient in vitro and perhaps in vivo transfection appears possible with ultrasound