Molecular structure of single DNA complexes with positively charged dendronized polymers

Area of Science:

• Polymer Chemistry
• Nanotechnology
• Biophysics

Background:

• Dendronized polymers are cylindrical nanoobjects with tunable radii and charge densities.
• These polymers possess protonated amine groups, leading to a positive charge.
• Complexation with DNA is a key step for potential gene delivery applications.

Purpose of the Study:

• To investigate the complexation of DNA with dendronized polymers of varying generations.
• To analyze the structural characteristics of these DNA-polymer complexes.
• To evaluate the potential of these complexes as nonviral gene delivery systems.

Main Methods:

• Synthesis of positively charged dendronized polymers with different dendron generations.
• Complexation of polymers with DNA.
• Adsorption of complexes onto mica substrates.
• Analysis using scanning force microscopy (SFM).

Main Results:

• DNA wraps around the dendronized polymers, forming complexes.
• The pitch of wrapped DNA was measured as 2.30 ± 0.27 nm (generation 2) and 2.16 ± 0.27 nm (generation 4).
• The DNA-dendronized polymer complex (generation 2) exhibited a negative charge, supporting the theory of spontaneous overcharging.

Conclusions:

• Dendronized polymers effectively complex with DNA, forming ordered structures.
• The observed DNA wrapping and overcharging phenomenon are significant for macromolecular complex design.
• These DNA-dendronized polymer complexes show promise for developing advanced nonviral gene delivery vectors.