Preparation of Thermosensitive Magnetic Block-Copolymer Hydrogel

• Main Authors: Ya-ting Chang, 張雅婷
• Other Authors: Yi-Chang Chung
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/81622891463443029191

碩士 === 國立高雄大學 === 生物科技研究所 === 101 === We employed magnetic nanoparticles incorporated with thermosensitive polymers to prepare intelligent gel. The chosen thermosensitive polymer was biocompatible Pluronic F127, which could be attached with caprolactone as a thermosensitive block-copolymer under investigation for its structure by FT-IR and,1H-NMR. The transition temperature could be controlled with added quantity of caprolactone. Based on the same solid content in polymer solutions, the phase transition range of PCL-Pluronic-PCL polymer is smaller than that of of Pluronic F127 polymer. As for the magnetic nanoparticles, we used superparamagnetic CoFe2O4 nanoparticles, prepared via a solid-state grinding method and characterized by FTIR, STEM, XRD, and SQUID. It was shown that nanoparticles had saturated flux of 78.7emu/g, and diameter of 10.6±4.0 nm. There were two polymers used to modify nanoparticle surfaces in order to improve nanoparticle dispersion: poly(acrylic acid) (PAA), and thermosensitive block copolymer, respectively. The modified nanoparticles were then blended with the thermosensitive block polymers in a certain ratios to fabricate intelligent gel. PAA was coated on the nanoparticle surfaces to enhance dispersity in water and prevent agglomeration. However, the PAA-coated nanoparticles was not dispersed in thick block copolymer aqueous solution, apparently leading to adverse effect on gelation. The other method was adopted to modify nanoparticle surfaces with the similar block-copolymer. Pluronic F127 and PCL-Pluronic-PCL were modified at the chain ends to introduce catechol groups, which could be then attached on magnetic nanoparticle surfaces. The similar thermosensitive polymer-coated nanoparticles could be dispersed into polymer sol system without precipitation. From experimental results, And then the polymer have OH group, can binding stably on the surface of magnetic nanoparticles. The lowest critical gelation temperature for 20wt% F127 solution changed from 23℃ to 20℃ with addition of CoFe2O4@Dopamine-F127-Dopamine; and the highest critical solution temperature of F127 solution also changed from 57℃ to 55℃. The transition temperature of F127 solution could be reduced due to nanoparticle addition. the magnetic thermosensitive hydrogel can be injected at a lower temperature in a sol state, and then the gel formation happens in situ at 37 ℃ suitable for storage in human body. The hydrogel can be dissolved again after initiation of hyperthermia process, showing a promising magnet-driven and thermosensitive drug carrier.