A comparison of shock wave and sinusoidal-focused ultrasound-induced localized transfection of HeLa cells

Both shock waves and sinusoidal continuous wave ultrasound can-mediate DNA transfer into cells, The relative transfection efficiencies of different ul trasound modalities are unclear. The purpose of this paper is to compare th e transfection efficiency of lithotripter shock waves and focused sinusoida l ultrasound in vitro. HeLa cells were transfected with beta-galactosidase and luciferase plasmid DNA reporter, Shock waves were generated by an elect romagnetic sound source, Sixty to 360 pulses at 1 Hz pulse frequency were a dministered at 13, 16 or 19 kV capacitor voltage. Sinusoidal focused ultras ound was generated by a single focus piezoceramic air-backed disk transduce r at a carrier frequency of 1.18 MHz operated in a pulsed mode, Compared to cells mixed with DNA only, shock waves induced up to eightfold more transf ected cells at a cell viability of 5%, while sinusoidal-focused ultrasound induced up to 80-fold more transfected cells at a cell viability of 45%, Th e corresponding transfection efficiencies of the HeLa cells were 0.08% for shock waves and 3% for focused ultrasound. These results may contribute to the selection of the ultrasound modality as a localized, noninvasive and sa fe tool to mediate gene transfer. (C) 1999 World Federation for Ultrasound in Medicine & Biology.