Figure 4.

DNA retardation and DNase I protection assay. (A) DNA-binding abilities of all PEI derivates were examined by agarose gel electrophoresis, and the examining mass ratios of PEI:DNA were 2:1 and 3:1 respectively. (B) PEI/DNA complexes were prepared at a ratio of 3:1 (w/w) and tested for their abilities to protecting DNA against the DNase I degradation.

Notes: +, samples treated with DNase I; –, samples treated with PBS.

Abbreviations: PEI, polyethyleneimine; TEG, triethyleneglycol; PEI-TEG, polyethyleneimine and triethyleneglycol polymer; A, mannosylated PEI-TEG derivative A; B, mannosylated PEI-TEG derivative B; C, mannosylated PEI-TEG derivative C; PEI25k, polyethyleneimine with a molecular weight of 25 kD.