Li Dongxiang, He Qiang, Zhu Haifeng, Tao Cheng, Li Junbai
Beijing National Laboratory for Molecular Sciences, International Joint Lab, CAS Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Zhong Guan Cun, Beijing 100080, PR China.
J Nanosci Nanotechnol. 2007 Sep;7(9):3089-94. doi: 10.1166/jnn.2007.637.
The physisorption of nonionic surfactant poly(ethylene glycol) (PEG) series and the chemisorption of carboxyl-terminated alkanethiols on surface of gold nanoparticles (AuNPs) were investigated. The physical adsorption of oligo(ethylene glycol) moieties introduced a tiny red shift of surface plasmon resonance (SPR) of AuNPs, indicating the formation of a protective layer of PEG molecules around gold surface. The subsequent chemisorption of omega-carboxyl alkanethiols was performed under the protection of PEG molecules, and the aggregation of metal nanoparticles did not appear by TEM observation. The successful adsorption of omega-carboxyl alkanethiol on gold surface was demonstrated according to FT-IR spectrum and the prior adsorbed PEG molecules could be washed out by centrifugation. Furthermore, the presence of nonionic surfactant even displayed a protective role in centrifugal process. The dispersity of modified AuNPs with peripheral functional groups was enhanced under the protection of PEG molecules as an important advantage in further biological applications.
研究了非离子表面活性剂聚乙二醇（PEG）系列在金纳米颗粒（AuNPs）表面的物理吸附以及羧基封端的链烷硫醇在其表面的化学吸附。聚乙二醇部分的物理吸附使AuNPs的表面等离子体共振（SPR）出现微小的红移，表明在金表面形成了PEG分子保护层。随后在PEG分子的保护下进行ω-羧基链烷硫醇的化学吸附，通过透射电子显微镜观察未出现金属纳米颗粒的聚集。根据傅里叶变换红外光谱证明了ω-羧基链烷硫醇成功吸附在金表面，并且预先吸附的PEG分子可以通过离心洗去。此外，非离子表面活性剂的存在在离心过程中甚至起到了保护作用。在PEG分子的保护下，具有外围官能团的改性AuNPs的分散性得到增强，这是其在进一步生物应用中的一个重要优势。
