title: Modification of gold nanorods using phosphatidylcholine to reduce cytotoxicity.
abstract: Hexadecyltrimethylammonium bromide (CTAB), which is necessary for the preparation of gold nanorods (NRs), was extracted from a NR solution into a chloroform phase containing phosphatidylcholine (PC). After three extractions, the zeta potential of the NRs remained positive, but its magnitude decreased from +67 +/- 1 to +15 +/- 1 mV. Transmission electron microscopy and energy-dispersive X-ray analysis indicated that the NRs were passivated with PC. The PC layer on the NR surface contributed to the prevention of NR aggregation. The PC-passivated NRs showed low cytotoxicity in comparison with twice-centrifuged NRs. It was shown that a negligible amount of CTAB was dispersed in the NR solution after the extraction. The extraction using a chloroform phase containing PC was found to be a convenient way of replacing the CTAB with alternative capping agents such as PC. This is a key technique for preparing functional NRs that can have practical applications.
authors.affiliation: Department of Materials Physics and Chemistry, Graduate School of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Takahashi
authors.forename: Yasuro
authors.initials: Y
authors.lastname: Niidome
authors.forename: Takuro
authors.initials: T
authors.lastname: Niidome
authors.forename: Kenji
authors.initials: K
authors.lastname: Kaneko
authors.forename: Hideya
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Sunao
authors.initials: S
authors.lastname: Yamada
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000302:isolation & purification / Q000633:toxicity; D002725:Chloroform; D003902:Detergents; D006046:Gold / Q000737:chemistry / Q000633:toxicity; D006367:HeLa Cells; D006801:Humans; D043942:Nanotubes / Q000737:chemistry / Q000633:toxicity; D010713:Phosphatidylcholines / Q000737:chemistry; D013499:Surface Properties
chemical_list: D002593:Cetrimonium Compounds; D003902:Detergents; D010713:Phosphatidylcholines; D006046:Gold; D002725:Chloroform; D000077286:Cetrimonium