Evaluation and Elucidation of DNA‐Containing Viologen Dendrimer Complex Formation

The syntheses of a tetracationic viologen and polycationic viologen dendrimers are described in this report. These water-soluble viologen dendrimers, the tetracationic viologen, and their DNA-containing complexes have been investigated by cyclic voltammetry (CV), electrophoresis, and atomic force microscopy with respect to their stability and effectiveness as possible transfection systems. The appearance of a negative potential shift and the loss of current in the cyclovoltammograms of viologen dendriplexes have been attributed to DNA/dendrimer complex formation. Oligomers of viologen with at least 4 positive charges are required for the formation of a primary DNA-viologen complex. The dynamics of the formation of a secondary complex was observed and studied by cyclic voltammetry. AFM measurements together with molecular modeling support the electrochemical results and show two different aggregates of the dendriplexes on gold.