Ring-opening polymerization for hyperbranched polycationic gene delivery vectors with excellent serum tolerance

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Gene Therapy

Background:

• Improving gene delivery vectors is crucial for effective gene therapy.
• Existing vectors like branched polyethylenimine (bPEI) face challenges with cytotoxicity and serum inhibition.

Purpose of the Study:

• To synthesize novel hyperbranched cationic polymers for enhanced gene transfection efficiency (TE) and biocompatibility.
• To evaluate the performance of these polymers, particularly their serum tolerance, compared to bPEI.

Main Methods:

• Synthesis of hyperbranched cationic polymers via ring-opening polymerization of diepoxide and polyamines.
• In vitro transfection experiments using plasmid DNA.
• Cytotoxicity assays, protein adsorption studies (BSA), DNase I degradation protection assays.
• Cellular uptake studies using flow cytometry and confocal laser scanning microscopy.
• Investigation of cellular uptake pathways using specific inhibitors.

Main Results:

• Polymers P1 and P5 demonstrated significantly higher TE than 25KDa bPEI.
• Transfection efficiency remained high or improved in the presence of serum, even up to 70% concentration.
• P1-P5 exhibited lower cytotoxicity and reduced protein adsorption compared to PEI.
• Enhanced DNA protection against DNase I degradation and consistent cellular uptake in serum were observed.
• Cellular uptake primarily occurred via caveolae and microtubule-mediated pathways.

Conclusions:

• Ring-opening polymerization is an effective method for creating gene delivery materials with high biological activity.
• The synthesized hyperbranched cationic polymers offer excellent serum tolerance and improved transfection efficiency.
• These novel polymers represent a promising advancement for gene delivery applications.