title: PEG shielded polymeric double-layered micelles for gene delivery.
abstract: A combination of A-B and B-C block copolymers was used to encapsulate DNA inside pEG coated particles, where A is a cationic block (poly(dimethylaminoethyl methacrylate), pDMAEMA) for DNA binding and condensation, B is a hydrophobic block (poly(butylmethacrylate), pBMA) and C is a polyethylene glycol (pEG) block. The AB and BC block copolymers were synthesized by transition metal mediated radical polymerization. The AB block copolymer had a fixed pBMA molecular weight of 3800 g/mol and a varying pDMAEMA molecular weight (from 22 to 65 kg/mol), the BC block copolymer had a fixed composition (pBMA 9000 g/mol; pEG 2000 g/mol). Plasmid DNA containing particles were made via a detergent dialysis method. By this method, particles of approximately 120 nm, as determined by dynamic light scattering (DLS), with a near neutral charge were formed, independent of the DMAEMA block size. DLS measurements and gel electrophoresis indicated that the particles were very stable in cell culture medium at 37 degrees C and resistant to anionic exchange by poly-l-aspartic acid. The particles were able to transfect COS-7 and OVCAR-3 cells with minor toxicity if incubated for 1 or 4 h; incubation for 24 h resulted in an increased toxicity. This paper shows that small polyplexes with near neutral charge can be obtained via a convenient detergent dialysis method using pDMAEMA-b-pBMA and pBMA-b-pEG. These particles may be interesting for in vivo experiments where particles with high positive charges have adverse interactions with blood components.
authors.affiliation: Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB, Utrecht, The Netherlands.
authors.forename: Arjen M
authors.initials: AM
authors.lastname: Funhoff
authors.forename: Sophie
authors.initials: S
authors.lastname: Monge
authors.forename: Rosalie
authors.initials: R
authors.lastname: Teeuwen
authors.forename: Gerben A
authors.initials: GA
authors.lastname: Koning
authors.forename: Nancy M E
authors.initials: NM
authors.lastname: Schuurmans-Nieuwenbroek
authors.forename: Daan J A
authors.initials: DJ
authors.lastname: Crommelin
authors.forename: David M
authors.initials: DM
authors.lastname: Haddleton
authors.forename: Wim E
authors.initials: WE
authors.lastname: Hennink
authors.forename: Cornelus F
authors.initials: CF
authors.lastname: van Nostrum
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D008823:Micelles; D011092:Polyethylene Glycols / Q000008:administration & dosage* / Q000737:chemistry; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry; D014162:Transfection / Q000379:methods*
chemical_list: D008823:Micelles; D011108:Polymers; D011092:Polyethylene Glycols