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Novel Amphiphilic Poly(N‐vinylpyrrolidone) Block Copolymer: Aggregative Behavior and Interaction with DNA
Author(s) -
Zhang Lifen,
Meng Lingzhi,
Lu Xiaoju,
Liu Yunhai
Publication year - 2008
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200850123
Subject(s) - copolymer , atom transfer radical polymerization , polymer chemistry , micelle , amphiphile , dynamic light scattering , dispersity , ethidium bromide , quenching (fluorescence) , chemistry , polymerization , aqueous solution , materials science , polymer , dna , organic chemistry , nanoparticle , fluorescence , nanotechnology , biochemistry , physics , quantum mechanics
Summary: Novel block copolymers poly(N‐vinylpyrrolidone)‐ block ‐poly[( tert ‐butoxy) carbonyl] tryptophanamido‐ N ′‐methacryl thiourea (PVP‐ b ‐PTAM‐I, II and III) were synthesized by atom transfer radical polymerization (ATRP) in DMF using PVP‐Cl as macroinitiator. The structures of the copolymers were characterized by UV‐vis and GPC‐MALLS. The results revealed that the copolymers with controlled molecular weight and relatively low polydispersity (PDI < 1.34) were obtained through ATRP. By means of dynamic light scattering (DLS) and transmission electron microscopy (TEM), we demonstrated that copolymer PVP‐ b ‐PTAM self‐aggregated to form spherical micelles in aqueous solution and the size of the micelles increased with increasing hydrophobic contents. The interaction of PVP‐ b ‐PTAM with DNA was explored using ethidium bromide (EB) quenching experiments. The interaction between PVP‐ b ‐PTAM and DNA markedly depended on both the copolymer concentration and composition. The PVP‐ b ‐PTAM‐II and III with higher hydrophobic contents exhibited highly complexed DNA ability at low copolymer concentration, such as 0.017 mg/mL, relative to PVP‐ b ‐PTAM‐I. As the copolymer concentration further increased for PVP‐ b ‐PTAM‐II and III, they first exhibited a sharply decreased affinity for DNA and then kept steady. The interaction mechanism between the amphiphilic copolymers and the EB‐DNA complex was discussed in detail.