Dicationic gemini surfactant gene delivery complexes contain cubic-lamellar mixed polymorphic phase

摘要

The characterization of structural properties of novel dicationic (gemini) surfactant-based DNA complexes as microano-scale self-assembling delivery systems for cutaneous gene therapy is described and discussed as related to measured transfection efficiencies. We have identified the Pn3m cubic phase in DNA-gemini-DOPE complexes with gemini surfactants having 12, 16 and 18:1 alkyl tail length. Increasing gemini/DNA charge ratios (ρ_(+/-)) from 0.5 to 10 resulted in increasingly mixed (Pn3m and H_Ⅱ or Pn3m and L) polymorphic systems with lamellar (L) features becoming more predominant. DNA-gemini complexes exhibited very weak single scattering peaks representative of gemini- plasmid particles with no long range order and low transfection efficiency. In gemini - DOPE complexes the main complex geometry is inverted hexagonal (H_Ⅱ) at low concentrations of gemini, with weakly ordered systems (generally lamellar) observed at increased concentrations. Overall, the presence of the newly identified cubic Pn3m phase in the DNA-gemini-DOPE complexes appears to be advantageous for increased transfection efficiency.