磁性奈米粒子之製備及其應用於磁性生物探針

Preparation of Magnetic Nanoparticles and Applications as Magnetic Bio-probes

吳千惠(Chien-Hui Wu)

指導教授 ： 凌永健

國立清華大學/理學院/化學系/碩士(2007年)

摘要

本研究製備表面修飾有去氧核糖核酸(DNA)的超順磁性奈米粒子，可以選擇性的與標的DNA結合，形成二維磁簇團雜合物，再利用高靈敏度的磁性量測，測定磁簇團與一般磁性奈米粒子的磁性差異，以開發利用磁性差異的磁性DNA探針。
製備方法為首先在油相中以高溫熱裂解法合成氧化鐵磁性奈米粒子，透過硫醇分子做表面官能化修飾，以穿透式電子顯微鏡、傅立葉紅外線光譜儀證實修飾後的磁性奈米粒子之粒徑均勻、分散性佳、表面修飾良好。接著將其與錳、鎳、鉛、鋅、銅重金屬元素結合，以感應藕合電漿質譜儀測定回收率，確認粒子表面官能基的活性。最後再利用橋接試劑將兩組相同長度不同序列之單股DNA(ssDNA)固定於磁性粒子表面，形成接有二種ssDNA的磁性核酸探針。
該探針可以選擇性的與互補序列之標的DNA結合，以膠體電泳確認為二維磁簇團雜合物，使用高靈敏度磁性測量儀器-超導量子干涉儀(SQUID)，測定該磁簇團與原先磁性奈米粒子之磁性表現差異，在磁滯曲線測量模式下，由磁飽和量(MS)與殘磁量(MR)可明顯看出兩者之差異，證實本研究所製備之磁性DNA探針，有潛力作為用磁性差異測量DNA的生醫分析工具。

關鍵字

磁性奈米粒子 ； 超順磁性

並列摘要

This research prepared superparamagnetic nanoparticles surface modified with single strand DNA, which would selectively bind to target DNA molecules and formed two-dimensional magnetic clusters. Using high sensitivity magnetic measurement, the magnetic difference between the as-formed magnetic clusters and native magnetic nanoparticles was clearly observed, demonstrating the feasibility of using magnetism difference to prepare magnetic DNA probes.
We prepared iron oxides magnetic nanoparticles by high temperature pyrolysis in oil phase. The hot-soup method was subsequently used to accomplish surface modification by thio-functional molecules. TEM and FT-IR were used to verify features of uniform particle size and surface functional group. The functionalized nanoparticles were reacted with Mn、Ni、Pb、Zn and Cu heavy metals for testing surface activities. Good recoveries obtained by ICPMS confirmed the expected surface activities. Two same-length and different-sequence ssDNA were bound to the functionalized nanoparticles using cross-linking reagent to form magnetic DNA probe.
The magnetic DNA probe would selectively bind to target complementary DNA, which was confirmed as magnetic-DNA cluster by PAGE analysis. Hysteresis loop measurements of magnetic-DNA clusters and magnetic nanparticles by SQUID show significant differences in magnetization saturation (MS) and magnetization remanence (MR). The results evidence that the magnetic DNA probe is of potential to detect DNA by magnetism differences in biomedical analysis.

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