Lim Yong Taik, Park O Ok, Jung Hee-Tae
Center for Advanced Functional Polymers, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea.
J Colloid Interface Sci. 2003 Jul 15;263(2):449-53. doi: 10.1016/s0021-9797(03)00322-9.
Gold nanolayer-encapsulated silica particles whose optical resonance is located in 750-900 nm spectral region were synthesized by combining Sn (tin)-surface seeding and a shell growing process. The synthesized composite particles can be potentially used in wide biological fields, due to biocompatibility and a well-known bioconjugation technique of gold layer. Sn atoms, which can act not only as a catalytic surface for reduction of gold but also as a linker between silica surface and gold nanoparticles, were chemically deposited on hydroxylated silica particles. Then, we introduced another reductant with gold chloride in order to produce a multilayer of Au shell. In the process, Au shells grew by the reduction of additional gold ions on the Sn-functionalized silica surface and resulted in the subsequent coalescence and growth of the deposited gold nanoparticles. Finally, a complete gold nanoshell was formed on the silica surface by the one-step method, without a repeated coating process. The deposition of a gold nanolayer on the silica particles was easily controlled by the concentration ratio of Sn-functionalized silica particles and gold chloride solutions. Transmission electron microscopy (TEM) images and optical extinction spectra clearly showed that gold nanolayers were successfully deposited on the silica surface by the novel method. As the gold colloids attached on the silica surface grew, their optical plasmon peak became red-shifted until complete a gold shell was formed. After the gold shell was completed, the optical plasmon resonance became blue-shifted and the extinction spectra were functions of a relative ratio of the core to shell thickness.
通过结合锡（Sn）表面种子法和壳生长过程，合成了光学共振位于750 - 900纳米光谱区域的金纳米层包裹的二氧化硅颗粒。由于其生物相容性以及金层广为人知的生物共轭技术，合成的复合颗粒在广泛的生物领域具有潜在应用价值。锡原子不仅可以作为还原金的催化表面，还能作为二氧化硅表面与金纳米颗粒之间的连接体，通过化学方法沉积在羟基化的二氧化硅颗粒上。然后，为了制备多层金壳，我们引入了另一种与氯化金反应的还原剂。在此过程中，金壳通过在锡功能化的二氧化硅表面上还原额外的金离子而生长，导致随后沉积的金纳米颗粒的聚结和生长。最后，通过一步法在二氧化硅表面形成了完整的金纳米壳，无需重复涂覆过程。金纳米层在二氧化硅颗粒上的沉积可通过锡功能化二氧化硅颗粒与氯化金溶液的浓度比轻松控制。透射电子显微镜（TEM）图像和光学消光光谱清楚地表明，通过这种新方法成功地在二氧化硅表面沉积了金纳米层。随着附着在二氧化硅表面的金胶体生长，其光学等离子体峰发生红移，直到形成完整的金壳。金壳形成后，光学等离子体共振发生蓝移，消光光谱是核壳厚度相对比例的函数。
