Loading capacity and interaction of DNA binding on catanionic vesicles with different cationic surfactants

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biotechnology

Background:

• Catanionic vesicles are self-assembled structures formed from mixtures of oppositely charged surfactants.
• These vesicles have potential applications in drug and gene delivery due to their ability to encapsulate molecules.
• Controlling the loading capacity and stability of DNA within these vesicles is crucial for effective gene therapy.

Purpose of the Study:

• To investigate the construction of catanionic vesicles using sodium laurate (SL) and alkyltrimethylammonium bromide (CnTAB) surfactants.
• To determine how the chain length of cationic surfactants influences DNA loading capacity and binding affinity.
• To elucidate the interaction mechanisms between DNA and catanionic vesicles, including vesicle stability and DNA conformation.

Main Methods:

• Construction of catanionic vesicles from varying ratios of SL and CnTAB (n=12, 14, 16).
• DNA loading capacity and binding saturation point (BSP) measurements.
• Analysis of vesicle-DNA interactions using (1)H NMR and Agarose Gel Electrophoresis (AGE).

Main Results:

• DNA loading capacity and affinity increased with the alkyl chain length of CnTAB surfactants.
• Catanionic vesicles exhibited re-aggregation or fusion upon DNA addition due to reduced surface charge density.
• DNA maintained its coiled state, and interactions induced vesicle deformation; L(-) dissociation from C14TAB-SL vesicles was observed with DNA addition, unlike in C12TAB-SL vesicles.

Conclusions:

• Catanionic vesicle properties, particularly DNA loading and affinity, can be tuned by adjusting the cationic surfactant chain length.
• The electrostatic interaction strength between surfactants and between DNA and surfactants dictates vesicle behavior upon DNA complexation.
• These findings offer guidance for selecting appropriate vectors for DNA delivery and advancing gene therapy applications.