Stability of poly(ethylene glycol)-graft-polyethylenimine copolymer/DNA complexes: influences of PEG molecular weight and PEGylation degree.
Polyethylenimine (PEI) is one of the most widely investigated cationic polymers for gene delivery. However, PEI/DNA complexes are unstable and tend to aggregate. PEGylation was used to improve the stability. The stability of polymer/DNA complexes was investigated including complexation stability, aggregation stability, sedimentation stability, and nuclease stability. PEI25K/DNA complexes were liable to aggregate to large particles (500-700 nm). The aggregation was proved to be induced by phosphate anion. In the medium without phosphate anion, aggregation was prevented by electrostatic repulsion. Owing to more efficient steric repulsion, PEG2 and PEG5K excelled PEG750 in facilitating copolymers to form stable small polyplexes (below 100 nm) without aggregation regardless of phosphate anion. The steric repulsion predominated over electrostatic repulsion in stabilization.
School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou, 510006, China. luoxin703@163.com
Xin
X
Luo
Shirong
S
Pan
Min
M
Feng
Yuting
Y
Wen
Wei
W
Zhang
D004247:DNA / Q000737:chemistry*; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods; D004355:Drug Stability; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry*; D011094:Polyethyleneimine / Q000031:analogs & derivatives* / Q000737:chemistry
D004337:Drug Carriers; D046911:Macromolecular Substances; C544016:poly(ethylene glycol)-co-poly(ethyleneimine); D011092:Polyethylene Glycols; D011094:Polyethyleneimine; D004247:DNA