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Synthesis, Assembled Structures, and DNA Complexation of Thermoresponsive Lysine-Based Zwitterionic and Cationic Block Copolymers

Ryosuke Kanto, Yehan Qiao, Kazunori Masuko, Hiroyuki Furusawa, Shigekazu Yano, Kazuhiro Nakabayashi, Hideharu Mori

Langmuir. 2019 Apr 2;35(13):4646-4659.

PMID: 30845801

Abstract:

A series of anionic, zwitterionic, and cationic lysine-based block copolymers with a thermoresponsive segment were synthesized by the reversible addition-fragmentation chain transfer (RAFT) polymerization of N-acryloyl- N-carbobenzoxy-l-lysine [A-Lys(Cbz)-OH], which contains a carboxylic acid and a protected amine-functionality in the monomer unit. Carboxylic acid-containing homopolymers, poly(A-Lys(Cbz)-OH), with predetermined molecular weights with relatively low polydispersities were initially synthesized by RAFT polymerization of A-Lys(Cbz)-OH. The chain extension of the dithiocarbamate-terminated poly(A-Lys(Cbz)-OH) to N-isopropylacrylamide (NIPAM) via the RAFT process and subsequent deprotection afforded the zwitterionic block copolymer composed of thermoresponsive poly(NIPAM) and poly(A-Lys-OH), which exhibited switchability among the zwitterionic, anionic, and cationic states by pH change. The assembled structures and thermoresponsive and chiroptical properties of these block copolymers were evaluated by dynamic light scattering, circular dichroism, and turbidity measurements. Finally, the cationic block copolymer, poly(A-Lys-OMe)- b-poly(NIPAM), was obtained by the methylation of the carboxylic acid group in the zwitterionic poly(A-Lys-OH) segment. Selective interactions of DNA with the cationic poly(A-Lys-OMe) segment in the lysine-based block copolymer were further evaluated by agarose gel electrophoresis and atomic force microscopy measurements, which revealed characteristic assembled structures and temperature-responsive properties of the polyplexes.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
LS74671 Poly(N-isopropylacrylamide), carboxylic acid terminated Poly(N-isopropylacrylamide), carboxylic acid terminated Price
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