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.

Temperature-tuned DNA condensation and gene transfection by PEI-g-(PMEO2MA-b-PHEMA) copolymer-based nonviral vectors

“…Nonetheless, there are still concerns over the long-term use of high molecular weight PEI in vivo. Recently, Cheng et al [17] coupled LMW PEI800 to the chain end of poly(N-isopropylacrylamide-co-N- (3-(dimethylamino)propylmethacrylamide))-(P(NIPAAm-co-NDAPM)) to construct a thermoresponsive nonviral vector, P(NIPAAm-co-NDAPM-b-PEI). This copolymer exhibited comparable and superior transfection efficiency to PEI25K, but lower cytotoxicity.…”

Synthesis and Investigation of a Novel pH- and Salt-Responsive Superabsorbent Hydrogel Based on Pectin

“…They are widely used in various applications such as hygienic, foods, cosmetics, and agriculture 1 . This accounts for increase in the worldwide production of superabsorbent polymers (SAPs) from 6000 tons in 1983 to 450000 tons in 1996 [2][3][4] . Nowadays, the worldwide production of SAPs is more than one million tons in year.…”

Responsive hydrogels with poly(N-isopropylacrylamide-co-acrylic acid) colloidal spheres as building blocks

“…Such smart hydrogels are considered to be highly potential for developing controlled drug and gene delivery systems [5][6][7][8][9][10], chemical-/bio-separations [11][12][13], adaptive liquid microlenses [14], soft machines [15], and sensors and/or actuators [16,17]. Hydrogels based on poly(N-isopropylacrylamide) (PNIPAM) polymer, which exhibit reversible volume-phase transition (swelling-deswelling volume change) in water responding to external temperature change around the lower critical solution temperature (LCST) [18,19], are typical and the most extensively investigated thermo-responsive hydrogels.…”