The efficiency of ultrasound-mediated gene transfection was enhanced three- to fourfold, compared to previous results, through the use of green fluorescent protein reporter gene, cultured immortalized human chondrocytes and artificial cavitation nuclei in the form of Albunex(®). Cells were exposed to 1.0-MHz ultrasound transmitted through the bottom of six-well culture plates containing immortalized chondrocytes, media, DNA at a concentration of 40 μg/mL and Albunex(®) at 50 x 106 bubbles/mL. Transfection efficiency increased linearly with ultrasound exposure pressure with a transfection threshold observed at a spatial average peak positive pressure (SAPP) of 0.12 MPa and reaching about 50% of the living cells when exposed to 0.41 MPa SAPP for 20 s. Adding fresh Albunex(®) at 50 x 106 bubbles/mL prior to sequential 1-s, 0.32- or 0.41-MPa exposures increased transfection with each exposure, reaching 43% transfection after four exposures. Efficient in vitro and in vivo transfection now appear possible with these enhancements.
- Bubble nucleation
- Gene therapy
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging