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Amphiphilic, low molecular weight poly(ethylene imine) derivatives with enhanced stability for efficient pulmonary gene delivery
Author(s) -
Roesler Susanne,
Koch Felix P. V.,
Schmehl Thomas,
Weissmann Norbert,
Seeger Werner,
Gessler Tobias,
Kissel Thomas
Publication year - 2011
Publication title -
the journal of gene medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 91
eISSN - 1521-2254
pISSN - 1099-498X
DOI - 10.1002/jgm.1538
Subject(s) - ethylene glycol , pegylation , transfection , chemistry , amphiphile , gene delivery , peg ratio , in vivo , polymer , ethylene oxide , polyethylene glycol , polymer chemistry , copolymer , biophysics , organic chemistry , biochemistry , biology , microbiology and biotechnology , finance , economics , gene
Background Poly(ethylene imine) (PEI) is a widely used transfection reagent for mammalian cells, but in vivo application of PEI 25 kDa is restricted by its toxicity. Low molecular weight (LMW) PEI is less toxic, but also less efficient than its high molecular weight equivalent, and prone to aggregation. Method A set of polymers was synthesized by coupling poly(ethylene glycol) (PEG) that contained either C 16/18 ‐chains (Cx‐EO) or butyl‐poly(propylene oxide)‐ co ‐poly(ethylene glycol) (ButPP). Critical micelle concentration (CMC) was determined for copolymers. Polyplexes were characterized by DNA binding ability, polyplex size and aggregation, hemolysis, and cytotoxicity. Transfection efficiency was tested in vitro and in vivo in mouse lungs. Results Copolymers formed stable complexes with DNA, and showed enhanced complex stability in isotonic solution for at least 1 h. CMC was determined for Cx‐EO‐PEI 4.7 and 8.3 at 0.0019 and 0.0037 m M , respectively; membrane activity in a haemolysis assay was demonstrated for ButPP‐PEI: both factors possibly enhance endosomal escape effect after PEGylation. IC 50 values of all synthesized polymers were in the range 6–33 ng/ml. Transfection efficiency of unmodified LMW‐PEIs was equivalent or better than that of PEI 25 as a result of aggregation in vitro . Cells treated with polyplexes of amphiphilic polymers showed reduced transfection compared to PEI 25. After instillation in mouse lungs, highest transfection efficiency was demonstrated with Cx‐EO copolymer of lowest molecular weight PEI. Conclusions A new set of polymers with low toxicity and high stability was synthesized, which contains promising candidates for pulmonary gene transfer, as documented by in vivo experiments in mice. Copyright © 2011 John Wiley & Sons, Ltd.