title: Temperature-responsive magnetite/PEO-PPO-PEO block copolymer nanoparticles for controlled drug targeting delivery.
abstract: In this study, temperature-responsive magnetite/polymer nanoparticles were developed from iron oxide nanoparticles and poly(ethyleneimine)-modified poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymer. The particles were characterized by TEM, XRD, DLS, VSM, FTIR, and TGA. A typical product has an approximately 20 nm magnetite core and an approximately 40 nm hydrodynamic diameter with a narrow size distribution and is superparamagnetic with large saturation magnetization (51.34 emu/g) at room temperature. The most attractive feature of the nanoparticles is their temperature-responsive volume-transition property. DLS results indicated that their average hydrodynamic diameter underwent a sharp decrease from 45 to 25 nm while evaluating the temperature from 20 to 35 degrees C. The temperature-dependent evolution of the C-O stretching band in the FTIR spectra of the aqueous nanoparticles solution revealed that thermo-induced self-assembly of the immobilized block copolymers occurred on the magnetite solid surfaces, which is accompanied by a conformational change from a fully extended state to a highly coiled state of the copolymer. Consequently, the copolymer shell could act as a temperature-controlled "gate" for the transit of guest substance. The uptake and release of both hydrophobic and hydrophilic model drugs were well controlled by switching the transient opening and closing of the polymer shell at different temperatures. A sustained release of about 3 days was achieved in simulated human body conditions. In primary mouse experiments, drug-entrapped magnetic nanoparticles showed good biocompatibility and effective therapy for spinal cord damage. Such intelligent magnetic nanoparticles are attractive candidates for widespread biomedical applications, particularly in controlled drug-targeting delivery.
authors.affiliation: Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Chen
authors.initials: C
authors.lastname: Guo
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Junhe
authors.initials: J
authors.lastname: Ma
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Liang
authors.forename: Liang-Rong
authors.initials: LR
authors.lastname: Yang
authors.forename: Hui-Zhou
authors.initials: HZ
authors.lastname: Liu
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D016503:Drug Delivery Systems; D004801:Eosine Yellowish-(YS) / Q000737:chemistry / Q000493:pharmacokinetics; D005260:Female; D005290:Ferric Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D007052:Ibuprofen / Q000737:chemistry / Q000493:pharmacokinetics; D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D011409:Propylene Glycols / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013499:Surface Properties; D013696:Temperature; D014018:Tissue Distribution
chemical_list: D005290:Ferric Compounds; C116176:PEO-PPO-PEO; D011409:Propylene Glycols; C000499:ferric oxide; D011092:Polyethylene Glycols; D004801:Eosine Yellowish-(YS); D007052:Ibuprofen