title: Correlating transfection barriers and biophysical properties of cationic polymethacrylates.
abstract: Transfection efficiencies of several polymeric gene carriers were compared and correlated quantitatively to the amounts of cellular accumulation of plasmid DNA and to the expression of mRNA by quantitative real-time polymerase chain reaction (real-time PCR). Three polycations polymers with similar chemical structure were used in this study: poly(dimethylamino)ethyl methacrylate (PDMA) homopolymer, PEO-b-PDMA copolymer, and PEO-b-poly(diethylamino)ethyl methacrylate (PEO-b-PDEA) copolymer. Despite their similar chemical structures, the transfection efficiencies were significantly different. PEO-b-PDEA copolymer was significantly less efficient as gene carrier as compared to both PDMA and PEO-b-PDMA. Correlations between cytotoxicity, cellular uptake of plasmid DNA, expression levels of transgene and protein, and the physical properties of the polymers were observed. With the PEO-b-PDEA studies, cytotoxicity was due primarily to the excess of polymers that did not participate in the DNA binding. In addition, the inability of the polymer/DNA polyplexes to interact with cell effectively was identified as a critical barrier for high efficiency of transfection. This study demonstrated that the use of quantitative real-time PCR in combination with physical characterization techniques could provide useful insights into the transfection barrier at different cellular levels.
authors.affiliation: Singapore-MIT Alliance, and Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Tan
authors.forename: T A
authors.initials: TA
authors.lastname: Hatton
authors.forename: K C
authors.initials: KC
authors.lastname: Tam
authors.forename: H P
authors.initials: HP
authors.lastname: Too
mesh_terms: D000178:Acrylamides; D002412:Cations; D002460:Cell Line; D002470:Cell Survival; D006801:Humans; D010957:Plasmids / Q000032:analysis / Q000493:pharmacokinetics*; D011092:Polyethylene Glycols; D016133:Polymerase Chain Reaction; D011109:Polymethacrylic Acids; D012333:RNA, Messenger / Q000032:analysis* / Q000096:biosynthesis; D014162:Transfection / Q000592:standards*
chemical_list: D000178:Acrylamides; D002412:Cations; D011109:Polymethacrylic Acids; D012333:RNA, Messenger; C429790:poly(N,N-dimethylacrylamide); D011092:Polyethylene Glycols