Versatile supramolecular pDNA vehicles via "click polymerization" of β-cyclodextrin with oligoethyleneamines

Herein, we report the efficient synthesis of high molecular weight polymers (up to 331 kDa) that contain β-cyclodextrin within the polymer backbone and the examination of these structures for pDNA delivery within cultured mammalian cells. Two series of polymers were synthesized, one with variation in oligoethyleneamine stoichiometry, Cd1₄₆, Cd2₄₄, Cd3₄₉, and Cd4₄₇ (1-4 oligoethyleneamines in the repeat unit, respectively and similar degree of polymerization, n_w = 44-49) and another with variation in polymer length (four ethyleneamines in the repeat unit), Cd4₂₇, Cd4₄₇, Cd4₉₃, and Cd4₂₀₀ [n_w = 27, 47, 93, 200] via the "click reaction". The two series of polymers revealed efficient pDNA binding and compaction through gel electrophoresis, dynamic light scattering, and transmission electron microscopy experiments. The DNase protection assay showed a decrease in pDNA degradation with an increase in the polymer amine stoichiometry, where polymer Cd3₄₉ and all of the Cd4 analogs completely protected pDNA for up to 8 h in serum. The cellular uptake and gene expression profiles were examined in HeLa cells, which similarly demonstrated that both the series of polymers had high pDNA delivery where, Cd3₄₉ and Cd4₉₃ had the most effective luciferase gene expression. In addition, the cell viability profiles were quite high with all of the structures.