Figure 3A: Effects of the ultrasound treatment on transfection efficiency of PEI-DNA complexes at various ratios. Cells were treated with PEI-DNA complexes and ultrasound or without (normal group) a low energy ultrasound for 10 sec and 9 cycles. Values are expressed as Mean ± SD in triple experiments. Statistics are shown for cells treated with ultrasound (p<0.01) compared to controls.