PEGylated quaternized copolymer/DNA complexes for gene delivery

Area of Science:

• Biomaterials Science
• Nanotechnology
• Gene Delivery Systems

Background:

• Developing effective and safe gene delivery vectors is crucial for gene therapy.
• Traditional gene delivery systems often face challenges with colloidal stability and non-specific interactions.
• Novel polymeric materials are being explored to overcome these limitations.

Purpose of the Study:

• To enhance the colloidal stability and reduce non-specific interactions of a novel gene delivery system.
• To evaluate the impact of PEGylation on the physicochemical properties, cellular uptake, and transfection efficiency of the gene delivery system.
• To assess the potential of the developed system for in vivo applications.

Main Methods:

• Synthesis of diblock 50/50 copolymer of epsilon-caprolactone and quaternized epsilon-caprolactone.
• Complexation of plasmid DNA with the copolymer using solvent evaporation and dialysis methods.
• Characterization of polyplexes including size, surface charge (zeta potential), and interaction degree.
• PEGylation of polyplexes using a poly(CL)-b-PEG copolymer.
• Evaluation of cytotoxicity, cellular uptake, and transfection efficiency in HeLa cells.

Main Results:

• Solvent evaporation yielded smaller complexes compared to dialysis.
• Polyplexes exhibited a positive zeta potential at a charge ratio of 4, indicating strong copolymer-plasmid DNA interaction.
• Cytotoxicity and transfection efficiency were comparable to polyethylenimine (PEI) 50 kDa.
• PEGylation increased particle size slightly but significantly reduced surface charge.
• PEGylated polyplexes showed reduced cytotoxicity, cellular uptake, and transfection efficiency compared to unshielded complexes.

Conclusions:

• The developed epsilon-caprolactone-based gene delivery system demonstrates promising characteristics.
• PEGylation effectively shields the polyplexes, reducing non-specific interactions and potentially improving in vivo biocompatibility.
• While PEGylation reduced cellular uptake and transfection efficiency in vitro, the enhanced stability suggests potential for in vivo gene delivery applications.