title: Preparation and characterization of thermo-responsive amphiphilic triblock copolymer and its self-assembled micelle for controlled drug release.
abstract: An amphiphilic thermo-responsive ABA triblock copolymer, poly(methyl methacrylate)-b-poly(N-isopropylacrylamide-co-poly(ethylene-glycol) methyl ether methacrlate)-b-poly(methyl methacrylate) (PMMA-b-P(NIPAM-co-PEGMEMA)-b-PMMA), was designed and synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, and subsequently characterized by FT-IR, (1)H NMR and GPC. The copolymer can disperse in water and self-assemble into nanoscaled micelles in a "flower-like" arrangement at room temperature; the hydrophobic PMMA tucks in the core while the hydrophilic and improved biocompatible P(NIPAM-co-PEGMEMA) forms a thermosensitive outer shell. The resulting micelles were investigated using fluorescence spectroscopy, dynamic light scattering technique (DLS) and transmission electron microscopy (TEM). The copolymer exhibited a lower critical solution temperature (LCST) of around 39 degrees C via optical transmittance measurements. Notably, there was no copolymer precipitation observed at the LCST, which was propitious to in vivo use of the micelle. The micelles loaded with folic acid as a model drug showed a desired thermo-responsive drug release behavior. It was found that the rate and amount (maximum percentage 85%) of the drug release was much higher above the LCST than that (maximum percentage 36%) below the LCST. These results indicate that the thermosensitive triblock copolymer possesses promising potential applications as a "smart" drug carrier in biomedical science.
authors.affiliation: Institute of Fine Chemical and Engineering, Henan University, Kaifeng, Henan, People's Republic of China.
authors.forename: Tianhong
authors.initials: T
authors.lastname: Qu
authors.forename: Airong
authors.initials: A
authors.lastname: Wang
authors.forename: Jinfang
authors.initials: J
authors.lastname: Yuan
authors.forename: Jiahua
authors.initials: J
authors.lastname: Shi
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Gao
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002850:Chromatography, Gel; D003692:Delayed-Action Preparations; D005492:Folic Acid / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008970:Molecular Weight; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D003692:Delayed-Action Preparations; D008823:Micelles; D011108:Polymers; D012996:Solutions; C052970:poly-N-isopropylacrylamide; D019904:Polymethyl Methacrylate; D005492:Folic Acid