Transfection and physical properties of various saccharide, poly(ethylene glycol), and antibody-derivatized polyethylenimines (PEI)
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Updated: Oct 17, 2026
Lentiviral Mediated Delivery of shRNAs to hESCs and NPCs Using Low-cost Cationic Polymer Polyethylenimine (PEI)
Published on: May 24, 2022
P Erbacher1, T Bettinger, P Belguise-Valladier
1Laboratoire de Chimie Génétique, UMR 7514 CNRS/Université Louis Pasteur de Strasbourg, Faculté de Pharmacie, Illkirch, France.
Background:
The ideal non-viral vector should be cell-type directed and form complexes with DNA that are physically stable, small and electrically neutral.
Methods:
We have synthesized several PEI derivatives that coat the PEI/DNA complexes with water-soluble residues able to stabilize the particles, to mask their surface charge and eventually to direct them to a particular tissue. The morphologies and sizes of the complexes were observed by TEM and DLS techniques, and their apparent surface charge was quantitated by zeta potential measurements; in vitro transfection efficacies were determined in serum-containing cell culture medium.
Results:
When compared to DNA complexes formed with the unmodified PEI, extensive grafting with maltose (15-25% of the amine functions) led to beneficial electrostatic shielding of the particle surface, but was unable to prevent aggregation in physiological salt concentration. More extended hydrophilic residues were therefore explored as a mean of physical repulsion between the particles. Low grafting (2.7%) with a linear dextran non-asaccharide led to small and stable toroids having no apparent surface charge, yet still reaching effective transfection levels. Electron microscopy of complexes with a higher extent of grafting showed worm-like structures unsuited for cell entry. Conjugation of PEI with as little as 0.5% of a terminally galactose-derivatized polyethyleneglycol (PEG)-3400 also gave neutral complexes of another worm-like structure that failed to transfect receptor-expressing hepatocytes.
Conclusion:
These results show that conjugation of large and flexible hydrophilic residues to PEI, while protecting the complexes from parasitic interactions also interfere with DNA condensation. PEG conjugation after PEI/DNA complex formation may avoid this problem, provided intracomplex reorganization is slow. Finally an anti-GD2 antibody (mAb) grafted with PEI was synthesized. The corresponding protein-coated DNA complexes were compact and small (50-60 nm), yet did not enhance transfection of GD2 ganglioside-expressing cells.
