title: The contribution of plasmid design and release to in vivo gene expression following delivery from cationic polymer modified scaffolds.
abstract: Tissue engineering scaffolds capable of gene delivery can provide a structure that supports tissue formation while also inducing the expression of inductive factors. Sustained release strategies are hypothesized to maintain elevated plasmid concentrations locally that can enhance gene transfer. In this report, we investigate the relationship between plasmid release kinetics and the extent and duration of transgene expression. Scaffolds were fabricated from polymer microspheres modified with cationic polymers (polyethylenimine, poly(L-lysine), poly(allylamine hydrochloride), polydiallyldimethylammonium) or polydopamine (PD), with PD enhancing incorporation and slowing release. In vivo implantation of scaffolds into the peritoneal fat pad had no significant changes in the level and duration of transgene expression between PD and unmodified scaffolds. Control studies with plasmid dried onto scaffolds, which exhibited a rapid release, and scaffolds with extended leaching to reduce initial quantities released had similar levels and duration of expression. Changing the plasmid design, from a cytomegalovirus (CMV) to an ubiquitin C (UbC) promoter substantially altered the duration of expression. These studies suggest that the initial dose released and vector design affect the extent and duration of transgene expression, which may be sustained over several weeks, potentially leading to numerous applications in cell transplantation and regenerative medicine.
authors.affiliation: Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA.
authors.forename: Misael O
authors.initials: MO
authors.lastname: Avilés
authors.forename: Chia-Hsuan
authors.initials: CH
authors.lastname: Lin
authors.forename: Marina
authors.initials: M
authors.lastname: Zelivyanskaya
authors.forename: John G
authors.initials: JG
authors.lastname: Graham
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Boehler
authors.forename: Phillip B
authors.initials: PB
authors.lastname: Messersmith
authors.forename: Lonnie D
authors.initials: LD
authors.lastname: Shea
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D000818:Animals; D002412:Cations; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods; D005818:Genetic Engineering / Q000379:methods; D019344:Lactic Acid / Q000737:chemistry*; D008297:Male; D008422:Materials Testing; D051379:Mice; D010957:Plasmids / Q000737:chemistry* / Q000235:genetics*; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011401:Promoter Regions, Genetic / Q000235:genetics; D014162:Transfection / Q000379:methods*; D019076:Transgenes / Q000502:physiology*
chemical_list: D002412:Cations; D004337:Drug Carriers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid