Gene transfection mediated by ultrasound and Pluronic P85 in HepG2 cells

In order to assess whether gene transfection could be mediated by ultrasound in association with P85 and find the appropriate parameters of ultrasound irradiation, the effects of ultrasound with or without P85 on gene transfection of HepG2 cells were examined. The HepG2 cells were irradiated by ultrasound at 1 MHz, 0.4-2.0 W/cm(2) and 50% duty cycle with plasmid encoding enhanced green fluorescent protein (EGFP) as a report gene. Forty-eight h later, the expression of EGFP was detected under the fluorescence microscopy. Transfection efficacy was quantitatively assessed by flow cytometry, and cell viability was evaluated by trypan blue exclusion. The results showed that the transfection efficacy was increased with the increases in ultrasound output power and the ideal transfection efficacy was achieved in HepG2 cells irradiated by ultrasound at 0.8 W/cm(2) for 30 s. The transfection efficacy in ulstrasound+P85 group was three times higher than in single ultrasound group [(17.63+/-1.07)% vs (5.57+/-0.56)%, P<0.05]. The cell viability was about 81% and 62% in ultrasound group and ultrasound+P85 group respectively. It was concluded that ultrasound in combination with P85 could mediate the gene transfection of HepG2 cells, ideal transfection efficacy was achieved by ultrasound irradiation at 0.8 W/cm(2) for 30 s, and P85 could somewhat increase the damage to cells caused by ultrasound.