The (ZnCl2)22@DAB-dendr-(Pyrr)64 dendrimer in all cell lines transported poorer siRNA-FITC to cells compared to lipofectamine (Figure , lower panel). In the THP1 cell line, after 24 and 48 hours, the transfection was 2.44% ± 1.34% and 6.47% ± 0.01%, respectively, and after 72 hours it increased to 58.5% ± 0.05% and this result, although the highest obtained for (ZnCl2)22@DAB-dendr-(Pyrr)64, is statistically significantly lower than the control transfection with lipofectamine. In the HeLa, HMEC1 and MCF7 cell lines, zinc-modified PAMAM-pyrr dendrimer practically did not transfect control siRNA. 56.15% ± 1.77%. Unfortunately, after 72h, the transfection efficiency for the dendrimer remained at the same level, while the transfection efficiency of lipofectamine increased, which consequently resulted in a loss of significant difference between the tested carriers.