title: Novel thermoresponsive nonviral gene vector: P(NIPAAm-co-NDAPM)-b-PEI with adjustable gene transfection efficiency.
abstract: A thermoresponsive cationic copolymer, poly( N-isopropylacrylamide- co- N-(3-(dimethylamino)propyl)methacrylamide)- b-polyethyleneimine (P(NIPAAm- co-NDAPM)- b-PEI), was designed and synthesized as a potential nonviral gene vector. The lower critical solution temperature (LCST) of P(NIPAAm- co-NDAPM)- b-PEI in water measured by UV-vis spectroscopy was 38 degrees C. P(NIPAAm- co-NDAPM)- b-PEI as the gene vector was evaluated in terms of cytotoxicity, buffer capability determined by acid-base titration, DNA binding capability characterized by agarose gel electrophoresis and particle size analysis, and in vitro gene transfection. P(NIPAAm- co-NDAPM)- b-PEI copolymer exhibited lower cytotoxicity in comparison with 25 kDa PEI. Gel retardation assay study indicated that the copolymer was able to bind DNA completely at N/P ratios higher than 30. At 27 degrees C, the mean particle sizes of P(NIPAAm- co-NDAPM)- b-PEI/DNA complexes decreased from 1200 to 570 nm corresponding to the increase in N/P ratios from 10 to 60. When the temperature changed to 37 degrees C, the mean particle sizes of complexes decreased from 850 to 450 nm correspondingly within the same N/P ratio range due to the collapse of thermoresponsive PNIPAAm segments. It was found that the transfection efficiency of P(NIPAAm- co-NDAPM)- b-PEI/DNA complexes was higher than or comparable to that of 25 kDa PEI/DNA complexes at their optimal N/P ratios. Importantly, the transfection efficiency of P(NIPAAm- co-NDAPM)- b-PEI/DNA complexes could be adjusted by altering the transfection and cell culture temperature.
authors.affiliation: Key Laboratory of Biomedical Polymers of Ministry of Education and Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Han
authors.initials: H
authors.lastname: Cheng
authors.forename: Jing-Ling
authors.initials: JL
authors.lastname: Zhu
authors.forename: Yun-Xia
authors.initials: YX
authors.lastname: Sun
authors.forename: Si-Xue
authors.initials: SX
authors.lastname: Cheng
authors.forename: Xian-Zheng
authors.initials: XZ
authors.lastname: Zhang
authors.forename: Ren-Xi
authors.initials: RX
authors.lastname: Zhuo
mesh_terms: D000178:Acrylamides / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D000818:Animals; D002021:Buffers; D002417:Cattle; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D005822:Genetic Vectors / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D006801:Humans; D010316:Particle Size; D011094:Polyethyleneimine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D013696:Temperature; D017186:Titrimetry; D014162:Transfection / Q000379:methods*
chemical_list: D000178:Acrylamides; D002021:Buffers; C531332:poly(N-isopropylacrylamide-co-N-(3-(dimethylamino)propyl)methacrylamide)-b-polyethyleneimine; D011094:Polyethyleneimine; D004247:DNA