Difference in the core-shell dynamics of polyethyleneimine and poly(l-lysine) DNA polyplexes

Area of Science:

• Biochemistry
• Materials Science
• Molecular Biology

Background:

• Electrostatic polymer-DNA complexes (polyplexes) are crucial for gene delivery.
• Significant variations in transfection efficacy exist among different polyplex materials.
• Polyethyleneimine (PEI) generally outperforms poly(l-lysine) (PLL) in mediating DNA transfection.

Purpose of the Study:

• To investigate the structural dynamics of DNA polyplexes.
• To compare material exchange between core and shell regions in PEI and PLL polyplexes.
• To correlate polyplex structural dynamics with DNA release and cellular transfection efficacy.

Main Methods:

• Utilized steady-state fluorescence spectroscopy.
• Employed double labeling based fluorescence resonance energy transfer (FRET) techniques.
• Analyzed structural dynamics and material exchange within polyplexes.

Main Results:

• Demonstrated distinct structural dynamics between PEI and PLL polyplexes.
• Observed core exchange occurring in PEI polyplexes.
• Found no core exchange in PLL polyplexes.

Conclusions:

• Core exchange in PEI polyplexes, absent in PLL polyplexes, is a key factor in their differing properties.
• Structural dynamics of polyplexes significantly influence DNA release mechanisms.
• These dynamics partially explain the observed differences in cellular transfection efficacy.