Temperature-Responsive Magnetite/PEO-PPO-PEO Block Copolymer Nanoparticles for Controlled Drug Targeting Delivery

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• 作者：Shu Chen ; Ying Li ; Chen Guo ; Jing Wang ; Junhe Ma ; Xiangfeng Liang ; Liang-Rong Yang ; Hui-Zhou Liu
• 刊名：Langmuir
• 出版年：2007
• 出版时间：December 4, 2007
• 年：2007
• 卷：23
• 期：25
• 页码：12669 - 12676
• 全文大小：1016K
• 年卷期：v.23,no.25(December 4, 2007)
• ISSN：1520-5827

文摘

In this study, temperature-responsive magnetite/polymer nanoparticles were developed from iron oxide nanoparticlesand 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 typicalproduct has an ~20 nm magnetite core and an ~40 nm hydrodynamic diameter with a narrow size distribution andis superparamagnetic with large saturation magnetization (51.34 emu/g) at room temperature. The most attractivefeature of the nanoparticles is their temperature-responsive volume-transition property. DLS results indicated that theiraverage hydrodynamic diameter underwent a sharp decrease from 45 to 25 nm while evaluating the temperature from20 to 35 C. The temperature-dependent evolution of the C-O stretching band in the FTIR spectra of the aqueousnanoparticles solution revealed that thermo-induced self-assembly of the immobilized block copolymers occurred onthe magnetite solid surfaces, which is accompanied by a conformational change from a fully extended state to a highlycoiled state of the copolymer. Consequently, the copolymer shell could act as a temperature-controlled "gate" for thetransit of guest substance. The uptake and release of both hydrophobic and hydrophilic model drugs were wellcontrolled by switching the transient opening and closing of the polymer shell at different temperatures. A sustainedrelease 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. Suchintelligent magnetic nanoparticles are attractive candidates for widespread biomedical applications, particularly incontrolled drug-targeting delivery.