Fluorination effect to intermediate molecular weight polyethylenimine for gene delivery systems

Area of Science:

• Biomaterials Science
• Gene Therapy
• Polymer Chemistry

Background:

• Polyethylenimine (PEI) is a common non-viral gene delivery vector.
• Enhancing PEI's properties, such as serum compatibility and cellular uptake, is crucial for effective gene therapy.
• Fluorination offers a potential strategy to modify PEI's physicochemical and biological characteristics.

Purpose of the Study:

• To synthesize and characterize fluorinated polyethylenimine (FP2ks) with varying degrees of fluorination.
• To evaluate the impact of fluorination on the physicochemical properties of FP2ks for gene delivery.
• To assess the cytotoxicity, cellular uptake, and transfection efficiency of FP2ks in gene delivery systems.

Main Methods:

• Synthesis of FP2ks via conjugation of intermediate molecular weight polyethylenimine with heptafluorobutyric anhydride.
• Characterization of FP2ks-pDNA complexes (polyplexes) for size, charge, and morphology.
• In vitro assessment of cytotoxicity, cellular uptake, and gene transfection efficiency, including serum compatibility studies.

Main Results:

• FP2ks successfully condensed pDNA into compact, positively charged, nano-sized spherical particles.
• Cytotoxicity of FP2ks increased with higher fluorination degrees, attributed to hydrophobic interactions and membrane disruption.
• Highly fluorinated FP2ks exhibited good serum compatibility and maintained transfection efficiency in serum-containing media.
• FP2ks showed higher cellular uptake but lower transfection efficiency than PEI25k, linked to compact polyplex formation and reduced pDNA dissociation.

Conclusions:

• Fluorination of polyethylenimine can modulate its properties for gene delivery applications.
• FP2ks demonstrates potential as a gene delivery vector with improved serum compatibility, though polyplex dissociation requires further optimization.
• Hydrophobic interactions play a significant role in FP2ks's interaction with DNA and cell membranes.
• Energy-dependent cellular uptake mechanisms and endosome buffering likely contribute to FP2ks-mediated transfection.