半導體螢光奈米粒子與磁性粒子於分析技術的開發

Abstract

本論文主要是將半導體奈米粒子與磁性粒子兩者所分別具有的優點相互結合，以開發新的分析技術為目標。本論文中以水溶性的CdSe奈米粒子為探針，感測水樣中所含的金屬離子，實驗結果顯示對於鎘離子溶液，CdSe奈米粒子會有螢光增強的效果，而金、銀、銅、汞等金屬離子溶液則會對CdSe奈米粒子產生螢光消減的情形，而為了使CdSe奈米粒子對於金屬離子更具有辨識性，利用二氧化鈦光觸媒包覆於磁性粒子上進行光還原金屬離子反應，用以區分銅和汞離子。 論文中也發展出新的合成螢光磁性粒子的方法，將CdSe/ZnS核殼結構半導體奈米粒子，與表面包覆有具硫醇官能基的溶膠凝膠磁性粒子，以硫-鋅共價鍵結的方式，將螢光奈米粒子與磁性粒子結合，並且將此螢光磁性粒子做更進一步的表面修飾，使DNA分子共價鍵結於粒子表面使其更具功能化。此外也以螢光磁性粒子做為探針，用以感測多巴胺分子，實驗結果發現多巴胺會導致螢光磁性粒子產生螢光消減的現象，且隨著多巴胺濃度增高，粒子螢光消減的情形越明顯。 本論文也將具羧酸官能基的分子螯合於磁性粒子表面，研究在不需額外加入質子源的情形下，以此粒子做為表面輔助雷射脫附游離質譜法中輔助樣品脫附游離的基質。經由實驗結果可知，此螯合有羧酸官能基分子的磁性粒子，確實具有輔助樣品脫附游離的效果。

Quantum dots and magnetic particles based analytical technology were developed in this dissertation. Water soluble CdSe quantum dots (QDs) were employed as the sensing probes for metal ions. The results demonstrated that the presence of gold, silver, copper, and mercury ions in sample solutions can quench the fluorescence of CdSe QDs, while the presence of cadmium ions are capable of enhancing the fluorescence of CdSe QDs. To differentiate mercury from copper ions, titania immobilized magnetic particles were employed to catalyze photo-reduction of the metal ions in sample solutions prior to CdSe QDs sensing. On the basis of the fluorescence changes of the sample mixed with CdSe QDs, before and after photo-reduction by titania beads, the metal ions can be roughly predicated using this approach. The second part of the dissertation demonstrated a new preparation method for generating CdSe/ZnS core/shell QDs immobilized Fe3O4 magnetic particles. Organic CdSe/ZnS core/shell QDs were trapped to the surfaces of magnetic particles in aqueous solution via thiol-zinc binding. The generated fluorescence magnetic particles have been modified with a strand of DNA, which was capable of probing its complementary DNA. Additionally, the newly generated fluorescent particles can be used to sense the presence of dopamine in sample solutions on the basis of the observation of the quenching of fluorescence. The final part of this dissertation presented a new matrix for surface-assisted laser desorption/ionization (SALDI) mass spectrometry. Carboxylic acid containing polymers immobilized magnetic particles were successfully demonstrated as the SALDI matrix without the need of the addition of proton source in the SALDI samples.