title: Reducible, dibromomaleimide-linked polymers for gene delivery.
abstract: Polycations have been successfully used as gene transfer vehicles both in vitro and in vivo; however, their cytotoxicity has been associated with increasing molecular weight. Polymers that can be rapidly degraded after internalization are typically better tolerated by mammalian cells compared to their non-degradable counterparts. Here, we report the use of a dibromomaleimide-alkyne (DBM-alkyne) linking agent to reversibly bridge cationic polymer segments for gene delivery and to provide site-specific functionalization by azide-alkyne cycloaddition chemistry. A panel of reducible and non-reducible, statistical copolymers of (2-dimethylamino)ethyl methacrylate (DMAEMA) and oligo(ethylene glycol)methyl ether methacrylate (OEGMA) were synthesized and evaluated. When complexed with plasmid DNA, the reducible and non-reducible polymers had comparable DNA condensation properties, sizes, and transfection efficiencies. When comparing cytotoxicity, the DBM-linked, reducible polymers were significantly less toxic than the non-reducible polymers. To demonstrate polymer functionalization by click chemistry, the DBM-linked polymers were tagged with an azide-fluorophore and were used to monitor cellular uptake. Overall, this polymer system introduces the use of a reversible linker, DBM-alkyne, to the area of gene delivery and allows for facile, orthogonal, and site-specific functionalization of gene delivery vehicles.
authors.affiliation: University of Washington, Department of Bioengineering and Molecular Engineering and Sciences Institute, William H. Foege Building, Box 355061, 3720 15th Ave NE, Seattle, WA 98195, USA. spun@uw.edu.
authors.forename: James-Kevin Y
authors.initials: JK
authors.lastname: Tan
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Choi
authors.forename: Hua
authors.initials: H
authors.lastname: Wei
authors.forename: Joan G
authors.initials: JG
authors.lastname: Schellinger
authors.forename: Suzie H
authors.initials: SH
authors.lastname: Pun
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D000818:Animals; D001386:Azides / Q000737:chemistry*; D002412:Cations / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D007700:Kinetics; D008301:Maleimides / Q000737:chemistry* / Q000633:toxicity*; D008689:Methacrylates / Q000737:chemistry*; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry*; D014162:Transfection
chemical_list: D000480:Alkynes; D001386:Azides; D002412:Cations; D004337:Drug Carriers; D008301:Maleimides; D008689:Methacrylates; D011108:Polymers; C049840:2-(dimethylamino)ethyl methacrylate