title: Thermosensitive PNIPAM-b-HTPB block copolymer micelles: molecular architectures and camptothecin drug release.
abstract: Two kinds of thermo-sensitive poly(N-isoproplacrylamide) (PNIPAM) block copolymers, AB4 four-armed star multiblock and linear triblock copolymers, were synthesized by ATRP with hydroxyl-terminated polybutadiene (HTPB) as central blocks, and characterization was performed by (1)H NMR, FT-IR and SEC. The multiblock copolymers could spontaneously assemble into more regular spherical core-shell nanoscale micelles than the linear triblock copolymer. The physicochemical properties were detected by a surface tension technique, nano particle analyzer, TEM, DLS and UV-vis measurements. The multiblock copolymer micelles had lower critical micelle concentration than the linear counterpart, TEM size from 100 to 120 nm and the hydrodynamic diameters below 150 nm. The micelles exhibited thermo-dependent size change, with low critical solution temperature about 33-35 °C. The characteristic parameters were affected by the composition ratios, length of PNIPAM blocks and molecular architectures. The camptothecin release demonstrated that the drug release was thermo-responsive, accompanied by the temperature-induced structural changes of the micelles. MTT assays were performed to evaluate the biocompatibility or cytotoxicity of the prepared copolymer micelles.
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China. Electronic address: luoyanl@snnu.edu.cn.
authors.forename: Yan-Ling
authors.initials: YL
authors.lastname: Luo
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Yang
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China. Electronic address: fengxu@snnu.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Xu
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
authors.forename: Ya-Shao
authors.initials: YS
authors.lastname: Chen
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D002070:Butadienes / Q000737:chemistry*; D002166:Camptothecin / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D006801:Humans; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008970:Molecular Weight; D012542:Scattering, Radiation; D017550:Spectroscopy, Fourier Transform Infrared; D013500:Surface Tension / Q000187:drug effects; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D002070:Butadienes; D008823:Micelles; C052970:poly-N-isopropylacrylamide; D002166:Camptothecin
keywords: Block copolymer; Cytotoxicity; Drug delivery; Micelle nanoparticles