Design and Synthesis of Magnetic Nanoparticles Capped by Amphiphilic Chitosan for Biomedical Application

• Main Authors: Kuan-Hsun Chen, 陳冠勳
• Other Authors: 謝之真
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/22189962855332908371

碩士 === 臺灣大學 === 化學工程學研究所 === 98 === Synthesis of magnetic nanoparticles (MNPs) has long been of scientific and technical interest due to their potential applications in tissue images, contrast enhancement to magnetic resonance imaging (MRI), and selective hybridization to nucleic acids. In this study, we employed NaIO4 to open the cyclic structure of chitosan and obtain periodate-oxidized chitosan that is further grafted with 1-hexadecylamine to form modified chitosan with amphiphilic feature. The alkylated chitosan could convert organically synthesized MNPs into aqueous phase by virtue of hydrophobic interaction. As shown in XRD and VSM analysis, MNPs exhibited superparamagnetic characteristics. TEM data showed that the average size of MNPs and the amphiphilic chitosan-capped MNPs (CMNPs) were 7 and 25 nm, respectively. In gene transfection study, CMNPs utilized positively charged chitosan to form complexes with plasmid pEGFP-N1 were co-cultured with colon HT-29 cancer cells with and without magnetic field. According to confocal microscopic images and cell viability assay, HT-29 cells could remain over 90% cell viability and express more green fluorescence proteins in the presence of magnetic field. In photodynamic therapy study, CMNPs conjugated with rose bengal (RB) were used to challenge HT-29 cells and then irradiated with 540 nm light emitting diode (LED) light. The singlet oxygen released from the illuminated cells were detected and accounted for the destruction of HT-29 cells.