title: Novel cationic pentablock copolymers as non-viral vectors for gene therapy.
abstract: New cationic pentablock copolymers of poly(diethylaminoethylmethacrylate) (PDEAEM), poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO)--PDEAEM-b-PEO-b-PPO-b-PEO-b-PDEAEM--synthesized in our laboratory were investigated for their potential as non-viral vectors for gene therapy. Agarose gel studies showed that the copolymers effectively condensed plasmid DNA to form polyplexes, and also protected plasmids against nuclease degradation. Light scattering and transmission electron microscopy were used to analyze the apparent size, molecular weight and morphology of these polyplexes. Lactate dehydrogenase assay was employed to find the cytotoxicity limits of the polymers and polyplexes on a human ovarian cancer cell line. The polymers showed much less cytotoxicity than commercially available ExGen 500 (linear polyethyleneimine). By changing the relative lengths of the blocks in the copolymers, it was found that the cytotoxicity of these copolymers could be tailored. The micellar structures of these copolymers in aqueous solutions and their pH-sensitive protonation were added advantages. In vitro transfection efficiencies of the polymers using green fluorescent protein (pEGFP-N1) and luciferase (pRL-CMV) reporter genes were found comparable to ExGen 500. Besides, aqueous solutions of these pentablock copolymers have been shown to exhibit thermodynamic phase transitions and thermoreversible gelation, a quality that could allow subcutaneous/intramuscular injections of these polymers for controlled gene delivery over time.
authors.affiliation: Department of Chemical Engineering, Iowa State University, 3035 Sweeney Hall, Ames, IA-50011-2230, USA.
authors.forename: Ankit
authors.initials: A
authors.lastname: Agarwal
authors.forename: Robert
authors.initials: R
authors.lastname: Unfer
authors.forename: Surya K
authors.initials: SK
authors.lastname: Mallapragada
mesh_terms: D002412:Cations; D045744:Cell Line, Tumor; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage* / Q000235:genetics*; D006801:Humans; D011108:Polymers / Q000008:administration & dosage*
chemical_list: D002412:Cations; D011108:Polymers