title: Thermoresponsive polymers as gene delivery vectors: cell viability, DNA transport and transfection studies.
abstract: A range of gene delivery vectors containing the thermoresponsive polymer, poly(N-isopropylacrylamide) (PNIPAm) was evaluated for effects on cell viability, intracellular trafficking and transgene expression in C2C12 mouse muscle cells. Polymers were complexed with plasmid DNA at pH 7.4 and the ability of the resulting particles to transfect cells was assessed via confocal microscopy and protein expression studies in tissue culture. Cell viability assays indicated that these polymers were toxic at high concentrations when not complexed to DNA or at certain polymer:DNA ratios. Poly(ethyleneimine) co-polymers with side-chain grafted PNIPAm were shown to be less toxic than poly(ethyleneimine) alone or PNIPAm-co-(N,N'-dimethylaminoethylmethacrylate) linear co-polymers and the effects were concentration dependent. Confocal micrographs of labeled polymers and DNA indicated rapid cellular entry for all the complexes but expression of Green Fluorescent Protein was achieved only when the branched PEI-PNIPAm co-polymers were used as vectors. The results indicate that design of appropriate co-polymer components and overall polymer architecture can be used to mediate, and perhaps ultimately control, DNA transport and transgene expression.
authors.affiliation: School of Pharmacy and Biomedical Sciences, University of Portsmouth, St. Michael's Building, White Swan Road, Portsmouth PO1 2DT, UK.
authors.forename: Beverley R
authors.initials: BR
authors.lastname: Twaites
authors.forename: Carolina
authors.initials: C
authors.lastname: de Las Heras Alarcón
authors.forename: Matthieu
authors.initials: M
authors.lastname: Lavigne
authors.forename: Annabelle
authors.initials: A
authors.lastname: Saulnier
authors.forename: Sivanand S
authors.initials: SS
authors.lastname: Pennadam
authors.forename: David
authors.initials: D
authors.lastname: Cunliffe
authors.forename: Dariusz C
authors.initials: DC
authors.lastname: Górecki
authors.forename: Cameron
authors.initials: C
authors.lastname: Alexander
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004247:DNA / Q000008:administration & dosage* / Q000378:metabolism; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000737:chemistry; D051379:Mice; D008809:Mice, Inbred C3H; D018613:Microscopy, Confocal; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism; D011108:Polymers / Q000737:chemistry*; D013696:Temperature; D013778:Tetrazolium Salts; D013844:Thiazoles; D014162:Transfection / Q000379:methods*
chemical_list: D000180:Acrylic Resins; D011108:Polymers; D013778:Tetrazolium Salts; D013844:Thiazoles; D049452:Green Fluorescent Proteins; C052970:poly-N-isopropylacrylamide; D004247:DNA; C022616:thiazolyl blue