title: Enhanced dispersity of gold nanoparticles modified by omega-carboxyl alkanethiols under the impact of poly(ethylene glycol)s.
abstract: 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.
authors.affiliation: 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.
authors.forename: Dongxiang
authors.initials: D
authors.lastname: Li
authors.forename: Qiang
authors.initials: Q
authors.lastname: He
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhu
authors.forename: Cheng
authors.initials: C
authors.lastname: Tao
authors.forename: Junbai
authors.initials: J
authors.lastname: Li
mesh_terms: D000327:Adsorption; D002627:Chemistry, Physical / Q000379:methods; D006046:Gold / Q000737:chemistry*; D007477:Ions; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared; D013438:Sulfhydryl Compounds; D020349:Surface Plasmon Resonance; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D007477:Ions; D013438:Sulfhydryl Compounds; D013501:Surface-Active Agents; D011092:Polyethylene Glycols; D006046:Gold