title: Low-molecular-weight polyethylenimine as a non-viral vector for DNA delivery: comparison of physicochemical properties, transfection efficiency and in vivo distribution with high-molecular-weight polyethylenimine.
abstract: Low-molecular-weight polyethylenimine (LMW-PEI) was synthesized by the acid-catalyzed, ring-opening polymerization of aziridine and compared with commercially available high-molecular-weight PEI (HMW-PEI) of 25 kDa. Molecular weights were determined by size-exclusion chromatography in combination with multi-angle laser light scattering. The weight average molecular weight (M(w)) of synthesized LMW-PEI was determined as 5.4+/-0.5 kDa, whereas commercial HMW-PEI showed a M(w) of 48+/-2 kDa. DNA polyplexes of LMW-PEI and HMW-PEI were characterized with regard to DNA condensation (ethidium bromide fluorescence quenching), size (photon correlation spectroscopy) and surface charge (laser Doppler anemometry). Compared with HMW-PEI, DNA condensation of LMW-PEI was slightly impaired at lower N/P ratios. Complexes with plasmid DNA at a N/P ratio of 6.7 showed significantly increased hydrodynamic diameters (590+/-140 vs. 160+/-10 nm), while the zeta-potential measurements were similar (23+/-2 vs. 30+/-3 mV). The cytotoxicity of LMW-PEI in L929 fibroblasts was reduced by more than one order of magnitude compared with HMW-PEI, as shown by MTT assay. LMW-PEI exhibited increased transfection efficiency in six different cell lines. Reporter gene expression was found to be increased by a factor of 2.1-110. The pharmacokinetics and biodistribution of 125I-PEI in mice were similar for both molecular weights with an AUC of ca. 330+/-100% ID/ml min. Approximately half of the injected dose accumulated in the liver. LMW-PEI proved to be an efficient gene delivery system in a broad range of cell lines. Due to differences in polyplex structure, as well as its relatively low cytotoxicity, which makes the application of high N/P ratios possible, LMW-PEI appears to possess advantageous qualities with regard to transfection efficiency over PEI of higher molecular weight.
authors.affiliation: Department of Pharmaceutics and Biopharmacy, Philipps University of Marburg, Ketzerbach 63, D-35032, Marburg/Lahn, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Kunath
authors.forename: Anke
authors.initials: A
authors.lastname: von Harpe
authors.forename: Dagmar
authors.initials: D
authors.lastname: Fischer
authors.forename: Holger
authors.initials: H
authors.lastname: Petersen
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bickel
authors.forename: Karlheinz
authors.initials: K
authors.lastname: Voigt
authors.forename: Thomas
authors.initials: T
authors.lastname: Kissel
mesh_terms: D000200:Action Potentials; D000818:Animals; D001774:Blood Chemical Analysis; D002460:Cell Line; D006224:Cricetinae; D004247:DNA / Q000235:genetics* / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects; D018014:Gene Transfer Techniques; D017930:Genes, Reporter / Q000235:genetics*; D005822:Genetic Vectors / Q000138:chemical synthesis* / Q000235:genetics*; D006801:Humans; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D011094:Polyethyleneimine / Q000138:chemical synthesis* / Q000378:metabolism* / Q000493:pharmacokinetics / Q000633:toxicity*; D013154:Spleen / Q000187:drug effects / Q000378:metabolism; D016482:Urinalysis
chemical_list: D007457:Iodine Radioisotopes; D011094:Polyethyleneimine; D004247:DNA