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Aim: To compare sonoporation effect of two phospholipids-based vectors-liposomes and microbubbles on cultured cell membrane., Methods: A breast cancer cell line SK-BR-3 was exposed to ultrasound alone, 2% or 5% liposome + ultrasound and 2% or 5% microbubble + ultrasound, separately. Immediately after the experiment and 24 h after ultrasound exposure, atomic-force microscopy (AFM) scanning was used to observe the membrane change of SK-BR-3 cells., Results: After ultrasound exposure, normal SK-BR-3 cells more or less lost their natural shape, showing elliptic outline with obtuse curved boundary. In groups added with phospholipids-based microbubbles, more obtuse curved boundary of cells was observed. The membrane pores of SK-BR-3 cells had apparent changes after ultrasound exposure. With AFM technique, membrane pores under ultrasound alone or ultrasound with liposomes conditions were enlarged, the diameter of some pores exceeding 1 microm. But all the membrane pores in these conditions returned to normal appearance after 24 hours. In ultrasound with 2% microbubble condition, most membrane pores were about 1 - 3 microm in size and returned to normal appearance after 24 h. In ultrasound with 5% microbubble condition, however, pores of most cell membrane porosity was about 2 - 4 pm and did not totally return to normal appearance after 24 h., Conclusion: At 2% concentration, phospholipids-based microbubble could enhance ultrasonic sonoporation effect and produce reparable membrane pores on SK-BR-3 cells, which appeared to be a promising vehicle for drug and gene delivery.

Aim: To investigate the feasibility of transfer antisense oligodeoxynucleotides (AS-ODNs) by the phospholipids-based gas-filled microbubbles (PGM) under ultrasound activation., Methods: An antisense oligodeoxynucleotides sequence ZL combined with luciferase reporter plasmid was used. A breast cancer cell line SK-BR-3 was exposed to different conditions to investigate the effects of such factors as ZL concentration, PGM concentration, mechanical index (MI) and ultrasound exposure duration on transfection efficiency and cell viability. The transfection efficiency and cell viability by other lipid vectors such as lipofectamine and liposome were also tested, whose results were comparied with that of PGM. Transfection efficiency was detected by fluorescence microscopy. Cell viability was verified by PI (propidium iodide) assay., Results: Among the factors tested, ultrasound exposure duration, MI and PGM concentration had obvious impacts on transfection efficiency and cell viability. The results showed that the optimal ultrasound condition was the exposure to ultrasound at MI 1.0 for 30 s with 2% PGM concentration, which gave an overall transfection efficiency of 78% +/- 10%, increased nearly 18 folds over the transfection by PGM (4.0%) or lipofectamine (4.3%) without ultrasound. Under same ultrasound conditions, different vectors showed significant difference in transfection efficiency while there are similar results in cell viability., Conclusion: Under proper ultrasound conditions, PGM can markedly enhance AS-ODNs transfection efficiency.