Next, we examined the effects of γ-CyDs on encapsulation ratios of pDNA into AF-liposomes ( Table 3 ). The encapsulation ratio of pDNA in pDNA/γ-CyD/AF-liposomes was significantly higher than those of pDNA/HP-γ-CyD/AFliposomes and pDNA/AF-liposomes. Meanwhile, the encapsulation ratios of γ-CyD and HP-γ-CyD into AF-liposomes were approximately 10.2% and 11.0%, respectively. These results suggest that γ-CyD improves the encapsulation of pDNA into AF-liposomes, although the extent of γ-CyD encapsulation into AF-liposomes is not high. In addition, both the encapsulation ratio of pDNA into AF-liposomes and gene transfer activity of pDNA/AF-liposomes were raised, as the number of the freeze-thaw cycle was increased, suggesting that the encapsulation of pDNA in AF-liposomes is correlated with the gene transfer activity of pDNA/AFliposomes (Table 4) .