我們設計具功能性的金奈米粒子，在感測金屬離子上的應用。金奈米粒子的合成是根據文獻，以檸檬酸還原金氯酸鹽(HAuCl4)。粒子大小及分布藉由穿透式電子顯微鏡(TEM)及掃描式電子顯微鏡(SEM)來觀察。而此功能性的金奈米粒子，我們利用合成出的聯吡啶硫醇分子HSC12EBiox [2,2’-bipyridinyl-3,3’-dicarboxylic acid bis-(12-mercapto-dodecyl) ester]及混和長鏈硫醇(decane-1-thiol)，在金奈米粒子表面做修飾。因為聯吡啶具有好的鉗合能力，加上金奈米粒子的靈敏的光學性質，所以可以用來偵測水中低濃度的金屬離子。 在過渡金屬離子(Zn2+, Cd2+, Hg2+, Cu2+, Pb2+)偵測時我們發現，當加入汞離子時，會造成SC12EBiox-GNPs的聚集，溶液顏色會由紅變紫。藉由吸收光譜的變化，我們可以看到Hg2+造成SC12EBiox-GNPs聚集的過程。 Surface functionalization of gold nanoparticles has been recognized as fundamental elements in the design of receptor-based sensor applications. We report herein the development of a functionalized gold nanoparticles (AuNPs) that allowed to be utilized for metal ion sensing. Gold nanoparticles were prepared by citric acid reduction of HAuCl4 according to published procedures. The particle size of AuNPs was confirmed by scanning electron microscope, scanning probe microscope and transmission electron microscopy. Functionalized gold nanoparticles were prepared by capping HSC12Ebiox, [2,2’-bipyridinyl-3,3’-dicarboxylic acid bis-(12-mercapto-dodecyl) ester], onto the surface of AuNPs along with decane-1-thiol. The well-documented chelating properties of bipyridine and the sensitivity of the optical properties of AuNPs have been employed to detect low concentration of metal ions in water. Upon addition of mercury(II) ion to the SC12EBiox-capped AuNPs, the aggregation of SC12EBiox-AuNPs was visualized by changing color from red to deep purple. UV-vis absorption spectrometer was employed to investigate the aggregation process. Isosbestic point was observed for each case.
